Calculation of myocardial mass index. End systolic size of the left ventricle. Echocardiography: description, normal values — «Online Diagnosis. The cost of the procedure

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general description

Echocardiography (EchoCG) is a method for studying morphological and functional changes in the heart and its valvular apparatus using ultrasound.

The echocardiographic research method allows:

Quantitatively and qualitatively assess the functional state of the LV and RV.
Assess regional LV contractility (for example, in patients with coronary artery disease).
Assess LVML and detect ultrasound signs of symmetric and asymmetric hypertrophy and dilatation of the ventricles and atria.
Assess the condition of the valvular apparatus (stenosis, insufficiency, valve prolapse, the presence of vegetations on the valve leaflets, etc.).
Assess the level of pressure in the LA and look for signs of pulmonary hypertension.
Identify morphological changes in the pericardium and the presence of fluid in the pericardial cavity.
Identify intracardiac formations (thrombi, tumors, additional chords, etc.).
Assess morphological and functional changes in the main and peripheral arteries and veins.

Indications for echocardiography:

suspicion of acquired or congenital heart defects;
auscultation of heart murmurs;
febrile states of uncertain cause;
ECG changes;
transferred myocardial infarction;
increased blood pressure;
regular sports training;
suspicion of a heart tumor;
suspected thoracic aortic aneurysm.

left ventricle

The main causes of local disorders of LV myocardial contractility:

Acute myocardial infarction (MI).
Postinfarction cardiosclerosis.
Transient painful and painless myocardial ischemia, including ischemia induced by functional exercise tests.
Permanent ischemia of the myocardium, which has still retained its viability (the so-called "hibernating myocardium").
Dilated and hypertrophic cardiomyopathy, which are often also accompanied by uneven damage to the LV myocardium.
Local disorders of intraventricular conduction (blockade, WPW syndrome, etc.).
Paradoxical movements of the IVS, for example, with volume overload of the pancreas or blockade of the legs of the bundle of His.

Right ventricle

The most common causes of impaired systolic function of the pancreas:

Tricuspid valve insufficiency.
Pulmonary heart.
Stenosis of the left atrioventricular orifice (mitral stenosis).
Atrial septal defects.
Congenital heart defects, accompanied by severe pulmonary arterial hydrangea (for example, VSD).
LA valve insufficiency.
Primary pulmonary hypertension.
Acute MI of the right ventricle.
Arrhythmogenic pancreatic dysplasia, etc.

An increase in normal values is observed, for example, in some heart defects.

Right atrium

Only the value of BWW is determined - the volume at rest. A value of less than 20 ml indicates a decrease in EDV, an indicator of more than 100 ml indicates its increase, and an EDV of more than 300 ml occurs with a very significant increase in the right atrium.

Heart valves

Echocardiographic examination of the valvular apparatus reveals:

fusion of the valve leaflets;
insufficiency of one or another valve (including signs of regurgitation);
dysfunction of the valvular apparatus, in particular papillary muscles, leading to the development of prolapse of the valves;
the presence of vegetation on the valve leaflets and other signs of damage.

The presence of 100 ml of fluid in the pericardial cavity indicates a small accumulation, and more than 500 ml indicates a significant accumulation of fluid, which can lead to heart compression.

Right ventricle

Myocardial mass: essence, norm, calculation and index, as it says

High blood pressure not only makes you feel worse, but also provokes the onset of pathological processes that affect target organs, including the heart: with arterial hypertension, left ventricular myocardial hypertrophy occurs.

This is due to an increase in the content of collagen in the myocardium and its fibrosis. An increase in myocardial mass entails an increase in myocardial oxygen demand. Which, in turn, leads to ischemia, arrhythmia and dysfunction of the heart.

However, myocardial hypertrophy is not a death sentence: people with a hypertrophied heart can live for decades. It is simply necessary to control blood pressure and regularly undergo an ultrasound of the heart in order to track hypertrophy over time.

This video talks about left ventricular hypertrophy, as this disease is directly related to the mass of the myocardium.

With an increased load on the myocardium, a gradual increase in its volume develops. This ultimately leads to hypertrophy.

Today, it is the main predictor of early S.S.S. and lethal outcome. This pathological process of the heart is also called the silent killer.

LV myocardial hypertrophy occurs twice as often among patients with high arterial hypertension than with its mild form. However, not only the increasing degree of blood pressure plays a major role in the formation of this pathology, but also morning rises in pressure, both in patients who received treatment for hypertension and those who did not undergo therapy.

The development of this disease is facilitated by various hemodynamic factors, namely, a violation of the rheological composition of the blood, an altered structure of the arteries, and a load on the heart by volume and pressure.

Biochemical factors include: increased activity of the sympathoadrenal system and (RAAS) renin-angiotensin-aldosterone system. The higher the angiotensin in the body, the more often hypertrophy of the left ventricular myocardium develops.

Among the genetic factors in the development of a pathological anomaly, a polymorphism of such a gene as ACE, which is a regulatory gene, is distinguished.

Hypertrophy of the LV myocardium is of two types: apical and symmetrical, which, as a rule, depends on the place where the heart tissue increases.

The main complaints of patients include pain in the heart, increased blood pressure, migraine, dizziness, general malaise, arrhythmia, which later turns into angina pectoris.

The first symptom of this disease is the appearance of shortness of breath with the subsequent development of fainting conditions or without them. Visually, no special changes are observed, but with a pronounced form of the pathological process, cyanosis of the skin is noted.

To diagnose LV myocardial hypertrophy, an ultrasound examination of the heart is used, which is considered the main diagnostic method with which it is possible to determine the existing increase in the heart muscle.

The second method of examination is the ECG. With this disease, the T wave changes, and the Q waves become pathological, revealing multiple extrasystoles with possible ventricular tachycardia. An alternative to the electrocardiogram is 24-hour monitoring.

Severe forms of the pathological disease require a surgical operation in order to resect the enlarged and altered portion of the myocardium. Also important is the observance of the regime of the day and nutrition, of course, the uniform distribution of physical activity with their possible limitation.

In men, the average mass of the myocardium of the left ventricle (norm) is 135 g, and in women 95 g. At the same time, the upper limit, the excess of which is considered an excess of the norm for men, is 183 g, and for women - 141 g.

If you have already undergone an ultrasound examination of the kidneys or, for example, abdominal organs, then you remember that in order to roughly decipher their results, you most often do not have to contact a doctor - you can find out basic information before visiting a doctor, when you read the conclusion yourself. The results of an ultrasound of the heart are not so easy to understand, so it can be difficult to unravel them, especially if you analyze each indicator by number.

You can, of course, just look at the last lines of the form, where the general summary of the study is written, but this also does not always clarify the situation. In order for you to better understand the results obtained, we present the basic norms of ultrasound of the heart and possible pathological changes that can be established by this method.

Norms in ultrasound for heart chambers

To begin with, here are a few numbers that are sure to be found in every conclusion of Doppler echocardiography. They reflect various parameters of the structure and function of individual chambers of the heart. If you are a pedant and take a responsible approach to decrypting your data, pay maximum attention to this section. Perhaps, here you will find the most detailed information, in comparison with other Internet sources intended for a wide range of readers. In different sources, the data may vary slightly; here are the figures based on the materials of the manual "Norms in Medicine" (Moscow, 2001).

Left ventricular parameters

Mass of the myocardium of the left ventricle: men - 135-182 g, women - 95-141 g.

Left ventricular myocardial mass index (often referred to as LVMI on the form): men 71-94 g/m2, women 71-89 g/m2.

End-diastolic volume (EDV) of the left ventricle (the volume of the ventricle that it has at rest): men - 112±27 (65-193) ml, women 89±20 (59-136) ml

End-diastolic size (EDD) of the left ventricle (the size of the ventricle in centimeters, which it has at rest): 4.6 - 5.7 cm

End systolic size (SSR) of the left ventricle (the size of the ventricle that it has during contraction): 3.1 - 4.3 cm

Wall thickness in diastole (outside heart beats): 1.1 cm

With hypertrophy - an increase in the thickness of the wall of the ventricle, due to too much load on the heart - this indicator increases. The numbers 1.2 - 1.4 cm indicate slight hypertrophy, 1.4-1.6 - medium, 1.6-2.0 - significant, and a value of more than 2 cm indicates high hypertrophy.

Ejection Fraction (EF) : 55-60%.

At rest, the ventricles fill with blood, which is not completely ejected from them during contractions (systole). The ejection fraction shows how much blood, relative to its total amount, is ejected by the heart with each contraction, normally it is a little more than half. With a decrease in the EF, they speak of heart failure, which means that the organ does not pump blood efficiently, and it can stagnate.

Stroke volume (the amount of blood that is ejected by the left ventricle in one contraction): 60-100 ml.

Right ventricular parameters

Wall thickness: 5ml

Size index 0.75-1.25 cm/m2

Diastolic size (size at rest) 0.95-2.05 cm

Parameters of the interventricular septum

Thickness at rest (diastolic thickness): 0.75-1.1 cm

Excursion (moving from side to side during heart contractions): 0.5-0.95 cm. An increase in this indicator is observed, for example, with some heart defects.

Right Atrium Parameters

For this chamber of the heart, only the value of the EDV is determined - the volume at rest. A value of less than 20 ml indicates a decrease in EDV, an indicator of more than 100 ml indicates its increase, and an EDV of more than 300 ml occurs with a very significant increase in the right atrium.

Parameters of the left atrium

Size: 1.85-3.3 cm

Size index: 1.45 - 2.9 cm/m2.

Most likely, even a very detailed study of the parameters of the heart chambers will not give you particularly clear answers to the question about your state of health. You can simply compare your performance with the optimal ones and, on this basis, draw preliminary conclusions about whether everything is generally normal for you. For more information, contact a specialist; For a broader coverage of it, the volume of this article is too small.

Norms in ultrasound for heart valves

As for deciphering the results of the examination of the valves, it should present an easier task. It will be enough for you to look at the general conclusion about their condition. There are only two main, most frequent pathological processes: these are stenosis and valve insufficiency.

term "stenosis" a narrowing of the valve opening is indicated, in which the upper chamber of the heart hardly pumps blood through it and may undergo hypertrophy, which we discussed in the previous section.

Failure is the opposite state. If the valve leaflets, which normally prevent the backflow of blood, for some reason cease to perform their functions, the blood that has passed from one chamber of the heart to another partially returns back, reducing the efficiency of the organ.

Depending on the severity of the violations, stenosis and insufficiency can be 1,2 or 3 degrees. The higher the degree, the more serious the pathology.

Sometimes in the conclusion of an ultrasound of the heart you can find such a definition as "relative insufficiency". In this condition, the valve itself remains normal, and blood flow disorders occur due to the fact that pathological changes occur in adjacent chambers of the heart.

Norms in ultrasound for the pericardium

The pericardium, or pericardial sac, is the "bag" that surrounds the outside of the heart. It fuses with the organ in the region of the vascular discharge, in its upper part, and between it and the heart itself there is a slit-like cavity.

The most common pathology of the pericardium is an inflammatory process, or pericarditis. In pericarditis, adhesions can form between the pericardial sac and the heart and fluid can accumulate. Normally, its 10-30 ml, 100 ml indicates a small accumulation, and over 500 - a significant accumulation of fluid, which can lead to difficulty in the full functioning of the heart and its squeezing ...

To master the specialty of a cardiologist, a person must first study at a university for 6 years, and then study cardiology separately for at least a year. A qualified doctor has all the necessary knowledge, thanks to which he can not only easily decipher the conclusion to, but also make a diagnosis based on it and prescribe treatment. For this reason, the interpretation of the results of such a complex study as ECHO-cardiography should be provided to a specialized specialist, and not try to do it on your own, long and unsuccessfully “poking around” in the numbers and trying to understand what these or those indicators mean. This will save you a lot of time and nerves, since you will not have to worry about your probably disappointing and, even more likely, wrong conclusions about your health.

The average value of the mass index of the left ventricular myocardium is 71 g/m2 in men and 62 g/m2 in women. The upper limit of this index is 94 and 89 g/m2, respectively.

The causes and mechanism of changes in the mass of the left ventricle in various diseases are still poorly understood.

Myocardial hypertrophy is a fundamental mechanism for the adaptation of the heart muscle to increased loads that occur both in cardiovascular diseases and during physical exertion. The heart muscle, like any muscle, thickens with an increased load on it.

The blood vessels that feed this organ do not keep up with its growth, so starvation of the heart tissues occurs and various diseases develop. With myocardial hypertrophy, problems also arise in the conduction system of the heart, as a result of which zones of abnormal activity appear in it and arrhythmias appear.

The best method for studying the anatomy of the heart and its function is echocardiography. In terms of sensitivity to cardiac hypertrophy, this method is superior to ECG. It is also possible to detect myocardial hypertrophy with the help of ultrasound of the heart.

Formula

MI=M/H2.7 or MI=M/S where

H - height (in m);

Causes

arterial hypertension;
various heart defects;

Stages and symptoms

compensation period;
subcompensation period;
decompensation period.

Treatment

Is it dangerous to increase the mass index of a lion. ventricle?

08/30/2014, Olga, 39 years old

Medications I take: occasionally I take lozap +, lasix, motherwort forte, valocordin

Duration P=76 QRS=92

intervals PQ=122 QT=319 QTc=352

axes P=22 QRS=45 T=30

computer interpretation of ECG: normal ECG

rhythm irregularity =5%

mean ventricular rate =79

normal sinus rhythm

normal position of the EOS in the frontal plane

mass index of the left ventricle 132g/m2 (norm 110)

I am disturbed by frequent dizziness, shortness of breath, constant heaviness in the head, no feeling of lightness and clarity, tearfulness, anxiety, an almost constant feeling of lack of air (as if it is difficult to breathe, there is not enough air when inhaling). I have stage 2 GB (I have been suffering from high blood pressure for a long time, more than 20 years, very high rates are rare, mostly fluctuating /), obesity, anxiety disorder, depression, asthenia, there are PA.

Tell me, please, is such an increase in the mass index of the left ventricle dangerous, which specialist should I see in the first place (therapist or psychiatrist), does it make sense to contact a cardiologist with these results?

2 Comments

In patients suffering from hypertension, sooner or later, thickening of the walls of the left ventricle (one of the chambers of the heart) develops. And the mass index of the LV myocardium, just depends on the thickness of the walls. Thus, in “experienced” hypertensive patients, an increased index corresponds to the diagnosis.

In itself, an increase in the index is not dangerous, but if we compare the risks for a healthy person and a patient with long-term hypertension, then, of course, they cannot be the same.

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How is the mass of the myocardium of the left ventricle calculated at home?

The mass index of the left ventricular myocardium is a figure that determines the exact weight of the patient's heart muscle in grams, obtained by calculating the specific data taken by the ultrasound machine during the heart scanning procedure. This index characterizes some cardiac pathologies associated with structural changes in the patient's myocardium and shows the degree of their severity.

The principle of calculating the mass of the LV myocardium

The mass of the myocardium of the left ventricle has a certain norm, any deviation from which indicates a disease affecting the heart or myocardium. Often, the data deviate upwards, and there is only one reason for this phenomenon - hypertrophy of the heart muscle.

Monitoring LV mass is recommended on an ongoing basis in order to be able to prevent serious cardiac pathology in advance. This is especially true for those patients who have an increased risk of hypertrophy. The normal result of the calculation after echocardiography is the mass of the left ventricle from 135 to 182 g if the patient is a man, and from 95 to 141 g in women.

However, we note that in some cases a slightly increased mass of the heart or myocardium is considered a physiological feature of a person that does not indicate the course of the disease in his body. To determine whether hypertrophy affects the heart or not, the doctor must compare the individual physical characteristics of the patient with the obtained size and weight of his myocardium. And only after the pathological nature of hypertrophy is confirmed, the doctor can make an approximate diagnosis, which must be confirmed by a number of additional laboratory and instrumental studies.

Causes affecting the deviation of the LV mass index of the myocardium from the norm

In most cases, the left ventricle and the myocardium as a whole increase under the influence of certain pathologies that provoke their significant overload of the heart:

valve defects;
cardiomyopathy;
arterial hypertension;
myocardial dystrophy.

In some cases, the mass of the heart muscle and tissue increases without exposure to hypertrophic pathologies. For example, if a man or woman is actively involved in sports, the myocardium is enriched with oxygen more intensively, as a result of which the thickness of the walls of these organs, as well as weight, increases significantly.

However, we note that hypertrophy as a disease is considered common among athletes, because a normal increase in myocardial mass over time can become a pathological abnormality requiring medical intervention. Typically, this phenomenon is observed in cases where the thickness of the patient's heart muscle significantly exceeds the size of his coronary arteries, as a result of which the left ventricle and the whole heart cease to receive a sufficient amount of blood. The result of such a deviation is heart failure, provoking a fatal outcome.

Important! In any case, an increased mass of the myocardium indicates serious stress on the left ventricle and heart of a person, due to which their hypertrophy occurs. Therefore, even if such a deviation, at first glance, is normal, it is still recommended not to allow it.

Methods for calculating the mass of the left ventricle of the myocardium

In most cases, the determination of IMM is performed using the ECHOCG procedure, based on the results of scanning the heart and myocardium in different modes. However, for an accurate calculation of the mass of the myocardium of the left ventricle, echocardiography alone is not enough, and the doctor will definitely need an additional image of the organs, in two- and three-dimensional projection.

You can scan the myocardium and left ventricle using a doppler or a special ultrasound machine that displays the projection of the organ on the screen in natural size. Many may wonder why the mass of only one left ventricle is calculated? The answer is simple: the left ventricle, unlike the right one, is subjected to much greater loads, due to which hypertrophy occurs more often in its cavity.

The very norm of the myocardial mass index is calculated in many ways, but today medicine uses only the two most effective formulas: ASE and PC, which include the following data:

the thickness of the heart muscle between the right and left ventricles;
the thickness of the posterior cavity of the left ventricle (this indicator is measured in two stages: when the organ is completely filled with blood and when it is emptied);
end-diastolic dimensions of the left ventricle.

If the mass of the myocardium is calculated using the ASE formula, then it should be taken into account that the thickness of the heart muscle also includes the thickness of the endocardium, which is not observed when calculating using the PC formula. Therefore, the name of the formula must be indicated in the protocol when calculating, since the initial mass differs slightly for them.

So, in order to determine the mass index of the left ventricle, it is initially required to scan the heart and myocardium, and substitute the resulting sizes of these organs into the following formula:

The abbreviations in this formula have the following designations:

IVS - the width of the septum between the ventricles, expressed in cm;
EDD - LV end-diastolic size;
ZLVZh - an indicator of the thickness of the posterior cavity of the left ventricle, expressed in cm.

Depending on who the patient is (male or female), the norm of the myocardial mass index will be slightly different. This difference looks like this:

If the patient is a man, then the norm for him will be from 135 to 182 grams;
If the patient is a woman, then for her the norm ranges from 95 to 141 grams.

With an overestimated indicator, it can be assumed that hypertrophy is rapidly developing in the patient's body, requiring urgent medical intervention.

Calculation of myocardial mass depending on the weight and height of the patient

To determine the stage of development of hypertrophy at the time of its diagnosis and to understand how dangerous it is for the patient's health, the doctor compares the size and mass of the myocardium with the height and weight of the patient. However, during this procedure, certain difficulties often arise.

If the patient is a man or woman over the age of 25, then his body is already fully formed, and the heart does not change its size in the future without the influence of negative factors, such as hypertrophy. However, if the patient has not reached the aforementioned age, then his myocardium is able to change its size and mass even without any pathology, which in turn will greatly complicate diagnosis.

As for the calculation of the ratio of myocardial mass to height and body weight, it is performed strictly according to the following formula:

The abbreviation of this formula is deciphered as follows:

M is the weight of the muscle, expressed in grams;
P is the patient's height;
P - the area of the patient's body, expressed in square meters.

After calculating the above parameters and establishing a relationship between them, the doctor determines whether the LV is hypertrophied or not, at what stage of development the pathology is at the time of the examination. However, this is not enough to make an accurate diagnosis; the patient will still have to undergo a number of additional laboratory and instrumental studies.

Left ventricular mass index

Left ventricular myocardial hypertrophy (LVH), as an element of its structural restructuring, is considered a sign of morphological deviation from the norm, a clear predictor of an unfavorable prognosis of the disease that caused it, as well as a criterion that determines the choice of active treatment tactics. Over the past twenty years, clinical studies have been conducted that have proven the independent contribution of drug-induced reduction in LV myocardial mass (LVML) in patients with arterial hypertension (AH), which makes it necessary to determine and control LVMM. Based on these ideas, recent recommendations on the diagnosis and treatment of hypertension include the measurement of LVML in the algorithm of antihypertensive management of patients in order to determine the presence of LVH.

But still, there is no unambiguous idea of the pathogenicity of LVH, which is associated with interrelated problems of both methodological and methodological order: The first relate to the reliability of the methods for determining LVML, the second - to evaluate the results obtained from the point of view of the presence or absence of LVH. In addition, there are numerous instrumental approaches to the determination of LVMM.

When measuring LVML, researchers are faced with multifactorial factors that have an impact on it. This is both the dependence of LVML on body size, and the possibility of only an adaptive increase in LVML, for example, during physical activity. There are also different sensitivity of instrumental methods for determining LVMM: some authors tend to have a higher sensitivity of MRI measurement.

All Echo-kg LVML calculations based on determining the difference in LV volumes across the epicardium and endocardium, multiplied by myocardial density, face problems in determining tissue interfaces and evaluating the shape of the left ventricle. At the same time, many methods are based on linear measurements in the M-mode under the control of the B-mode, or directly in a two-dimensional image. The previously existing problem of identifying tissue interfaces, such as "pericardium-epicardium" and "blood-endocardium", in recent years, in general, has been resolved, but requires a critical attitude to studies of past years and does not relieve researchers from the need to use all the technical capabilities of US -scanners.

Individual differences in LV geometry prevent the creation of its universal mathematical model even in the absence of local violations of the LV structure and the approximation of its shape to an ellipse, which gave rise to a large number of formulas, and, consequently, criteria for determining LVH, which results in different conclusions about the presence of hypertrophy in one and the same patient.

In addition, several calculation formulas for determining LVML are currently used. The formulas recommended by the American Society of Echocardiography (ASE) and Penn Convention (PC) are more commonly used, using three measured parameters: the thickness of the myocardium of the interventricular septum (IVS), the posterior LV wall (PLV) at the end of diastole and its end-diastolic size (EDD) with inclusion (ASE formula) or not inclusion of endocardial thickness (PC formula) in the diameter of the left ventricle, depending on the formula used. But the results obtained when applying these formulas are not always comparable, therefore, to interpret the data obtained, it is necessary to clarify the method used to calculate the parameters of the left ventricle, which in practice is not always available or is neglected. The reason for the discrepancy lies in the following. The cubic formula originally recommended by ASE was suggested by B.L. Troy et al. in 1972 (LVML, gr = [(EDV+IVL+ZLV) 3 -EKD 3 ]×1.05) and then modified using the R.B. regression equation. Devereux and Reichek in 1977 (Penn Convention formula) by analyzing the relationship between echocardiographic LVML and post-mortem LV anatomical mass in 34 adults (r=0.96, p<0,001) (ММЛЖ, гр = 1,04×[(КДР+МЖП+ЗСЛЖ) 3 -КДР 3 ]-13,6) .

The discrepancies in the values of the calculated LVML obtained using these two formulas (the cubic one proposed by B.L. Troy and the PC formula) were within 20% and in 1986 R.B. Devereux, D.R. Alonso at.all. based on autopsy, 52 patients proposed an adjusted equation (LVML, r = 0.8×+0.6 - ASE formula). LVML determined by the PC formula closely correlated with LVML at autopsy (r=0.92; p<0,001), переоценивала наличие ГЛЖ лишь на 6%, а чувствительность у пациентов с ГЛЖ (масса миокарда при аутопсии >215 gr.) was 100% with a specificity of 86% (in 29 of 34 patients). The cubic formula similarly correlated with LVML at autopsy (r=0.90; p<0,001), но систематически переоценивала наличие ГЛЖ (в среднем на 25%), что было устранено введением скорректированного уравнения (формула ASE): ММЛЖ=0,8×(ММЛЖ-кубическая формула)+0,6 гр. Однако, при её использовании наблюдалась недооценка ММЛЖ при аутопсии в пределах 30% .

Less popular, but sometimes used, is the Teicholz formula (LVML = 1.05 × ((7 × (RDR + TZSLV + TMZhP) 3) / 2.4 + KDR + TZSLV + TMZhP) - ((7 × KDR 3) / (2 ,4+KDR))) . According to L. Teicholz, LVMM is the norm<150 гр,гр - умеренной, а >200 gr - pronounced LVH. However, these parameters can only be guidelines when using the Teicholz formula and, in addition, they do not take into account the ratio of LVML to body size.

Virtual calculation of LVML using the above three formulas with a stable value of one of the parameters (either the sum of the thickness of the IVS and RSLV, or CDR) and an increase in the other (either CDR, or the sum of the thickness of the IVS and RSLV, respectively) by a stable arbitrary value, showed different sensitivity of the formulas to changing linear indicator. It turned out that the ASE formula is more sensitive to an increase in the thickness of the myocardial walls, the Teicholz formula is more sensitive to an increase in the LV cavity, and the PC formula parity takes into account changes in the linear dimensions and thickness of the myocardium and the cavity. Thus, it is better to evaluate LVML by changing the thickness of the myocardium using more sensitive formulas in this respect - ASE and PC.

The second problem, in addition to the definition of LVML, is the lack of unified criteria for its indexation, and, consequently, the formation of LVH criteria. Determining the size of organs through their allometric dependencies on body weight, adopted in comparative morphology, is unacceptable in the human population due to the variability of the body weight of an individual, which depends on many factors, in particular on constitutional features, physical development, and also a possible change in the size of an organ as a result of a disease. .

The presence of a direct dependence of LVML on body size requires its indexation. In this regard, the mass index of the left ventricular myocardium (LVMI) is more often calculated with standardization to the body surface area (BSA). There are several more ways to calculate the myocardial mass index: by height, height 2.0, height 2.13, height 2.7, height 3.0; correction using a regression model of LVML depending on age, body mass index and BSA.

Past studies prove the influence of various factors on myocardial mass in different age groups. So, in early childhood, the weight of the LV myocardium is mainly determined by the number of cardiomyocytes (CMC), which reach a maximum number during the first year of life, in the future, the growth of the LV depends on the increase in the size of the CMC (physiological hypertrophy) and this physiological process is influenced by many factors - body size, blood pressure, blood volume, genetic factors, salt intake, blood viscosity, which determine the phenotypic increase in LV mass. After puberty, other factors already determine the degree of physiological hypertrophy, while in adults there is a relationship between LVMH and age. The effect of height on LVML variability was studied by de G. Simone et al. and in 1995 on 611 normotensive individuals with normal body weight aged 4 months to 70 years (including 383 children and 228 adult patients). LVMH was normalized to body weight, height, BSA. Height-indexed 2.7 LVML increased with height and age in children, but not in adults, suggesting an influence of other variables on adult LV mass.

Thus, the influence of various factors on the variability of LVML in children and adults does not allow the use of the same approaches to the assessment and diagnosis of LVLV. At the same time, indexation to a height of 2.7 is more justified in children than in adults, who may have an overestimation of this criterion.

The correction of LVML to BSA, calculated according to the Du Bois formula, is more often used, but this standardization is imperfect, because it underestimates LVML in people with obesity.

Analyzing data from the Framingham Heart Study and using the Penn Convention formula for growth indexing D. Levy, R.J. Garrison, D.D. Savage et al. LVH was defined as the deviation of LVML values from the mean ± 2SD in the control group, i.e. 143 gr/m for men and 102 gr/m for women. Over four years of follow-up, cardiovascular morbidity (CVD) was higher in individuals with larger LVMI: in men with LVMI<90 гр/м она составила 4,7% против 12,2% при ИММЛЖ ≥140 гр/м, у женщин - 4,1% и 16,1% соответственно . Наблюдался рост ССЗ при более высокой ММЛЖ у мужчин в 2,6, а у женщин - в 3,9 раза, что доказывает прогностическую значимость и важность правильной оценки массы миокарда, поиска более точных диагностических критериев ГМЛЖ для раннего её выявления.

In the domestic DAH-1 recommendations, the criterion for diagnosing LVMH is the highest level of the norm - the value of LVMI is more than 110 g/m 2 in women and 134 g/m 2 in men, although a value of more than 125 g is prognostically unfavorable in men with arterial hypertension (AH) / m 2.

The frequency of detection of LVMH in both obesity and CVD increases with indexation to growth (growth 2.7), however, there are not enough data yet to judge the additional prognostic value of this approach.

Comparison of different LVML indexes for mortality risk prediction was studied by Y. Liao, R.S. Cooper, R. Durazo-Arvizu et al. (1997) in 998 patients with cardiac pathology during a 7-year follow-up. A high correlation between different indexations was found (r=0.90-0.99). At the same time, an increase in any of the indices was associated with a threefold risk of death from all causes and heart disease. 12% of individuals with LVMH based on height indexation had a moderate increase in LVML with no increase in risk, although overweight was common in this group, indicating that indexation for height was justified in the presence of obesity. Thus, myocardial hypertrophy detected using different indexing equally retains its prognostic value in relation to the risk of death.

P. Gosse, V. Jullien, P. Jarnier et al. investigated the relationship between LVMI and mean daily systolic blood pressure (MAP) as measured by ambulatory blood pressure monitoring (ABPM) in 363 untreated hypertensive patients with antihypertensive drugs. LVM indexation was carried out according to BSA, height, height 2.7, and the data obtained were analyzed taking into account gender. LVMH corresponding to SBP >135 mm Hg. Art., was considered as a criterion for LVMH. A higher percentage of LVH detection was found during indexation of LVML by growth of 2.7 (50.4%) and growth (50.1%), and LVH detection during indexation by BSA was 48.2% due to its decrease in obese individuals, therefore scientists conclude that the LVMH criterion is more sensitive when indexed by height 2.7 and suggest that cutoff points be considered a value exceeding 47 g/m 2.7 in women and 53 g/m 2.7 in men.

The above ambiguous ideas about the normal values of LVMI, LVMI and LVH criteria are presented in Table 1.

LVMI as a criterion for LVLV with and without gender

D. Levy, Framingham Research, 1987

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

Recommendations for chamber quantification: Guidelines, 2005

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

A large range of scatter of LVMI standards within one indexation is obvious, and, consequently, there is uncertainty in the conclusions about the presence of myocardial hypertrophy. Indexing of LVMI according to PPT gives a range of criteria from 116 to 150 g/m 2 in men games/m 2 in women; indexation to growth 2.0 for men games/m 2.7 for women; indexation to height - 77, for men and 69, g/m. Therefore, it is impossible to confidently judge the presence or absence of LVMH when the value of LVMI falls within the range of scatter of normal criteria. In addition, it is important that a large proportion of patients with mild or moderate LVMH, which is characteristic of a large group of people with mild hypertension, will fall into this indefinite interval.

The definition of LVML is also important for characterizing a disproportionately high LVML (LVMML), since the absolute values of the actual mass are included in the formula for calculating the disproportionality coefficient that determines the presence and severity of LVMLV. An increase in LVML to a greater extent than required by the hemodynamic load was found in individuals both with and without LVH and was associated with an increased risk of cardiovascular complications, regardless of the presence of LVH.

So, despite the 30-year use of Echo-kg as a criterion for determining LVMH, there remains inconsistency in various studies, there is no presentation of a universal standardization method, although each of the listed criteria is based on fairly large studies, some of which are supported by autopsy data. The optimal way to normalize LV mass remains controversial, and the use of different indexing causes confusion in threshold values, disorients the work of scientists and practitioners in choosing the best indexing and interpretation of the results, while maintaining the relevance of choosing a method for calculating LVMI. The controversy of examination methods was also stated by other authors, who believe that studies of large population cohorts are needed to compare heart sizes measured by different methods, develop more accurate standards, select the best indexing methods, and identify factors affecting LVML, many of which remain undisclosed.

It is possible that before searching for optimal algorithms for determining LVML and its standardization in AH, one should clarify which of the above methods is the most comparable with the others in assessing LVH. For this purpose, a discriminant analysis, in which the group formation criterion was one of the methods for diagnosing LVH, and all other methods together were predictors, revealed that such a technique is the PC formula with standardization according to BSA (Table 2).

Correspondence of the incidence of LVH according to different methods of its determination

(performance ratio (KFR) in %; p<0,001)

All methods except dependent

Note: PCppt, PCgrowth, PCgrowth 2.7 - PC formula, indexation to PPT, growth and growth 2.7, respectively; ASEppt, ASEgrowth, ASEgrowth 2.7 - ASE formula, indexation to PPT, growth and growth 2.7, respectively.

On the other hand, the greatest predictor value for LVH (CFR=95.7%), revealed by discriminant analysis, of the combination of ABPM, integral structural and functional parameters of the left ventricle and a number of regulatory peptides only in the case of using the MS technique with standardization to BSA also testified in favor of its greatest adequacy for the diagnosis of LVH.

Onishchenko Alexander Leonidovich, Doctor of Medical Sciences, Professor, Vice-Rector for Research, SBEI DPO NGIUV MOH of Russia, Novokuznetsk;

Filimonov Sergey Nikolaevich, Doctor of Medical Sciences, Professor, Vice-Rector for Academic Affairs of the State Budgetary Educational Institution of Education and Science of the NGIUV of the Ministry of Health of Russia, Novokuznetsk.

Bibliographic link

URL: http://science-education.ru/ru/article/view?id=23603 (date of access: 03/08/2018).

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Left ventricular myocardial mass index normal

general description

Echocardiography (EchoCG) is a method for studying morphological and functional changes in the heart and its valvular apparatus using ultrasound.

The echocardiographic research method allows:

Quantitatively and qualitatively assess the functional state of the LV and RV.
Assess regional LV contractility (for example, in patients with coronary artery disease).
Assess LVML and detect ultrasound signs of symmetric and asymmetric hypertrophy and dilatation of the ventricles and atria.
Assess the condition of the valvular apparatus (stenosis, insufficiency, valve prolapse, the presence of vegetations on the valve leaflets, etc.).
Assess the level of pressure in the LA and look for signs of pulmonary hypertension.
Identify morphological changes in the pericardium and the presence of fluid in the pericardial cavity.
Identify intracardiac formations (thrombi, tumors, additional chords, etc.).
Assess morphological and functional changes in the main and peripheral arteries and veins.

Indications for echocardiography:

suspicion of acquired or congenital heart defects;
auscultation of heart murmurs;
febrile states of uncertain cause;
ECG changes;
transferred myocardial infarction;
increased blood pressure;
regular sports training;
suspicion of a heart tumor;
suspected thoracic aortic aneurysm.

left ventricle

The main causes of local disorders of LV myocardial contractility:

Acute myocardial infarction (MI).
Postinfarction cardiosclerosis.
Transient painful and painless myocardial ischemia, including ischemia induced by functional exercise tests.
Permanent ischemia of the myocardium, which has still retained its viability (the so-called "hibernating myocardium").
Dilated and hypertrophic cardiomyopathy, which are often also accompanied by uneven damage to the LV myocardium.
Local disorders of intraventricular conduction (blockade, WPW syndrome, etc.).
Paradoxical movements of the IVS, for example, with volume overload of the pancreas or blockade of the legs of the bundle of His.

Right ventricle

The most common causes of impaired systolic function of the pancreas:

Tricuspid valve insufficiency.
Pulmonary heart.
Stenosis of the left atrioventricular orifice (mitral stenosis).
Atrial septal defects.
Congenital heart defects, accompanied by severe pulmonary arterial hydrangea (for example, VSD).
LA valve insufficiency.
Primary pulmonary hypertension.
Acute MI of the right ventricle.
Arrhythmogenic pancreatic dysplasia, etc.

Interventricular septum

An increase in normal values is observed, for example, in some heart defects.

Right atrium

Heart valves

Echocardiographic examination of the valvular apparatus reveals:

fusion of the valve leaflets;
insufficiency of one or another valve (including signs of regurgitation);
dysfunction of the valvular apparatus, in particular papillary muscles, leading to the development of prolapse of the valves;
the presence of vegetation on the valve leaflets and other signs of damage.

The presence of 100 ml of fluid in the pericardial cavity indicates a small accumulation, and more than 500 ml indicates a significant accumulation of fluid, which can lead to heart compression.

Norms

Left ventricular parameters:

The mass of the myocardium of the left ventricle: men -g, women -g.
The mass index of the myocardium of the left ventricle (in the form is often referred to as LVMI): men g / m 2, women g / m 2.
End-diastolic volume (EDV) of the left ventricle (the volume of the ventricle that it has at rest): men - 112 ± 27 (65-193) ml, women 89 ± 20 (59-136) ml.
End-diastolic size (EDD) of the left ventricle (the size of the ventricle in centimeters, which it has at rest): 4.6-5.7 cm.
The end systolic size (SSR) of the left ventricle (the size of the ventricle that it has during contraction): 3.1-4.3 cm.
Wall thickness in diastole (outside heart contractions): 1.1 cm. With hypertrophy - an increase in the thickness of the ventricular wall due to too much stress on the heart - this figure increases. The numbers 1.2-1.4 cm indicate slight hypertrophy, 1.4-1.6 - medium, 1.6-2.0 - significant, and a value of more than 2 cm indicates high hypertrophy.
Ejection fraction (EF): 55-60%. The ejection fraction shows how much blood, relative to its total amount, is ejected by the heart with each contraction, normally it is a little more than half. With a decrease in the EF index, they speak of heart failure.
Stroke volume (SV) - the amount of blood that is ejected by the left ventricle in one contraction: ml.

Right ventricular parameters:

Wall thickness: 5 ml.
Size index 0.75-1.25 cm / m 2.
Diastolic size (size at rest) 0.95-2.05 cm.

Parameters of the interventricular septum:

Thickness at rest (diastolic thickness): 0.75-1.1 cm. Excursion (moving from side to side during heart contractions): 0.5-0.95 cm.

Parameters of the left atrium:

Norms for heart valves:

Norms for the pericardium:

In the pericardial cavity, there was normally no more fluid.

Formula

The mass of the myocardium of the left ventricle (calculation) is determined by the following formula:

IVS - value (in cm) equal to the thickness of the interventricular septum in diastole;
KDR - a value equal to the end-diastolic size of the left ventricle;
ZLVZH - a value (in cm) equal to the thickness of the posterior wall of the left ventricle in diastole.

MI - myocardial mass index is determined by the formula:

MI=M/H2.7 or MI=M/S where

M is the mass of the myocardium of the left ventricle (in g);
H - height (in m);
S is the surface area of the body (in m2).

Causes

Causes of left ventricular hypertrophy include:

arterial hypertension;
various heart defects;
cardiomyopathy and cardiomegaly.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm. Often hypertrophy develops with mitral valve insufficiency or with aortic defects.

The reasons why myocardial mass may exceed the norm are divided into:

Scientists have found that the presence or absence of several fragments in human DNA can contribute to cardiac hypertrophy. Of the biochemical factors leading to myocardial hypertrophy, an excess of norepinephrine and angiotensin can be distinguished. Demographic factors in the development of cardiac hypertrophy include race, age, gender, physical activity, a tendency to obesity and alcoholism, and salt sensitivity. For example, in men, myocardial mass is higher than normal more often than in women. In addition, the number of people with a hypertrophied heart increases with age.

Stages and symptoms

In the process of increasing the mass of the myocardium, three stages are distinguished:

compensation period;
subcompensation period;
decompensation period.

Symptoms of left ventricular hypertrophy begin to manifest themselves significantly only at the stage of decompensation. With decompensation, the patient is concerned about shortness of breath, fatigue, palpitations, drowsiness and other symptoms of heart failure. Specific signs of myocardial hypertrophy include dry cough and swelling of the face, which appear in the middle of the day or in the evening.

Consequences of left ventricular myocardial hypertrophy

High blood pressure not only makes you feel worse, but also provokes the onset of pathological processes that affect target organs, including the heart: with arterial hypertension, left ventricular myocardial hypertrophy occurs. This is due to an increase in the content of collagen in the myocardium and its fibrosis. An increase in myocardial mass entails an increase in myocardial oxygen demand. Which, in turn, leads to ischemia, arrhythmia and dysfunction of the heart.

Cardiac hypertrophy (increased mass of the myocardium of the left ventricle) increases the risk of developing cardiovascular disease and can lead to premature death.

Treatment

The method of treating left ventricular myocardial hypertrophy depends on the cause that caused the development of this pathology. If necessary, surgery may be prescribed.

Heart surgery for myocardial hypertrophy can be aimed at eliminating ischemia - stenting of the coronary arteries and angioplasty. With myocardial hypertrophy due to heart disease, if necessary, prosthetic valves or dissection of adhesions are performed.

Slowing down the processes of hypertrophy (if it is caused by a sedentary lifestyle) can in some cases be achieved by using moderate physical activity, such as swimming or running. Obesity may be the cause of left ventricular myocardial hypertrophy: normalizing weight during the transition to a balanced diet will reduce the load on the heart. If hypertrophy is caused by increased loads (for example, during professional sports), then they should be gradually reduced to an acceptable level.

Medicines prescribed by doctors for left ventricular hypertrophy are aimed at improving myocardial nutrition and normalizing heart rhythm. When treating myocardial hypertrophy, you should stop smoking (nicotine reduces the supply of oxygen to the heart) and drinking alcohol (many drugs used in myocardial hypertrophy are not compatible with alcohol).

How is the muscular system of the heart

The myocardium is the thickest layer of the heart, located in the middle between the endocardium (inner layer) and the epicardium outside. A feature of the heart is the ability of the atria and ventricles to contract on their own, independently of each other, even "work" offline.

Contractility is provided by special fibers (myofibrils). They combine features of skeletal and smooth muscle tissue. That's why:

distribute the load evenly across all departments;
have a striated striation;
ensure the non-stop work of the heart throughout a person’s life;
are reduced regardless of the influence of consciousness.

Each cell has an elongated nucleus with a large number of chromosomes. Due to this, myocytes are more “survivable” compared to cells of other tissues and are able to withstand significant loads.

The atria and ventricles have different myocardial density:

In the atria, it consists of two layers (superficial and deep), which differ in the direction of the fibers, transverse or circular myofibrils are located outward, and longitudinal myofibrils are located inside.
The ventricles are provided with an additional third layer, lying between the first two, with a horizontal direction of the fibers. Such a mechanism strengthens and maintains the force of contraction.

What does myocardial mass indicate?

The total weight of the heart in an adult is about 300 g. The development of ultrasound diagnostic methods made it possible to calculate the part related to the myocardium from this weight. The average myocardial mass for men is 135 g, for women - 141 g. The exact mass is determined by the formula. It depends on:

the size of the left ventricle in the diastolic phase;
thickness of the interventricular septum and posterior wall.

Even more specific for diagnosis is such an indicator as the myocardial mass index. For the left ventricle, the norm for men is 71 g / m2, for women - 62. This value is calculated automatically by a computer when entering data on a person's height, body surface area.

Mechanism of contraction of the heart

Thanks to the development of electron microscopy, the internal structure of the myocardium, the structure of the myocyte, which provides the property of contractility, has been established. Thin and thick protein chains, called "actin" and "myosin", were revealed. When actin fibers slide over myosin fibers, muscle contraction occurs (the systole phase).

The biochemical mechanism of contraction is the formation of a common substance "actomyosin". In this case, potassium plays an important role. Leaving the cell, it promotes the connection of actin and myosin and the absorption of energy by them.

The energy balance in myocytes is maintained by replenishment in the relaxation phase (diastole). Biochemical components are involved in this process:

oxygen,
hormones,
enzymes and coenzymes (vitamins of group B are especially important in their role),
glucose,
lactic and pyruvic acids,
ketone bodies.
amino acids.

What influences the contraction process?

Any diastolic dysfunction impairs energy production, the heart loses "feeding", does not rest. Myocyte metabolism is influenced by:

nerve impulses coming from the brain and spinal cord;
lack or excess of "components" for a biochemical reaction;
violation of the supply of necessary substances through the coronary vessels.

The blood supply to the myocardium is carried out through the coronary arteries extending from the base of the aorta. They go to different parts of the ventricles and atria, break up into small branches that feed the deep layers. An important adaptive mechanism is the system of collateral (auxiliary) vessels. These are reserved arteries that are normally collapsed. For their inclusion in the blood circulation, the main vessels must fail (spasm, thrombosis, atherosclerotic damage). It is this reserve that is able to limit the zone of infarction, provides compensation for nutrition in case of thickening of the myocardium during hypertrophy.

Maintaining satisfactory contractility is essential to prevent heart failure.

Properties of the heart muscle

In addition to contractility, the myocardium has other exceptional properties that are inherent only in the muscle tissue of the heart:

Conductivity - equates myocytes to nerve fibers, since they are also able to conduct impulses, passing them from one area to another.
Excitability - for 0.4 sec. the entire muscular structure of the heart comes into excitation and provides a full-fledged ejection of blood. The correct rhythm of the heart depends on the occurrence of excitation in the sinus node located deep in the right atrium and the further passage of the impulse along the fibers to the ventricles.
Automatism - the ability to independently form a focus of excitation, bypassing the established direction. This mechanism causes disruption of the correct rhythm, as other areas take on the role of the driver.

Various myocardial diseases are accompanied by minor or severe violations of the listed functions. They determine the clinical features of the course and require a special approach to treatment.

Consider pathological changes in the myocardium and their role in the occurrence of certain diseases of the heart muscle.

Types of myocardial damage

All myocardial injuries are divided into:

Non-coronary diseases of the myocardium - characterized by the absence of a connection between causes and damage to the coronary arteries. These include inflammatory diseases or myocarditis, dystrophic and nonspecific changes in the myocardium.
Coronary - consequences of impaired patency of the coronary vessels (foci of ischemia, necrosis, focal or diffuse cardiosclerosis, cicatricial changes).

Features of myocarditis

Myocarditis is often found in men, women and in childhood. Most often they are associated with inflammation of certain areas (focal) or the entire muscular layer of the heart (diffuse). The causes are infectious diseases (flu, rickettsiosis, diphtheria, scarlet fever, measles, typhoid fever, sepsis, poliomyelitis, tuberculosis).

Carrying out preventive work on the formation of a sufficient protective reaction with the help of vaccinations made it possible to limit the disease. However, serious problems remain in the heart after diseases of the nasopharynx, due to the development of a chronic rheumatic process. Non-rheumatic myocarditis is associated with a severe stage of uremic coma, acute nephritis. An autoimmune nature of the inflammatory reaction is possible, proceeding as an allergy.

Histological examination among muscle cells reveals:

granulomas of a typical structure in rheumatism;
edema with accumulation of basophils and eosinophils;
death of muscle cells with proliferation of connective tissue;
accumulation of fluid between cells (serous, fibrinous);
areas of dystrophy.

The result in all cases is impaired myocardial contractility.

The clinical picture is varied. It consists of symptoms of heart and vascular insufficiency, rhythm disturbances. Sometimes the endocardium and pericardium are simultaneously affected.

Usually, right ventricular failure develops more often, since the right ventricular myocardium is weaker and the first to fail.

Patients complain of shortness of breath, palpitations, a feeling of interruption against the background of an acute illness or after an infection.

Rheumatic inflammation is always accompanied by endocarditis, the process necessarily extends to the valvular apparatus. With a delay in treatment, a defect is formed. For a good response to therapy, temporary arrhythmias and conduction disturbances are typical without consequences.

Myocardial metabolic disorders

Metabolic disorders often accompany myocarditis and coronary heart disease. It is not possible to find out what is primary, this pathology is so connected. Due to the lack of substances for energy production in cells, lack of oxygen in the blood in thyrotoxicosis, anemia, beriberi, myofibrils are replaced by scar tissue.

The heart muscle begins to atrophy, weaken. This process is characteristic of old age. A special form is accompanied by the deposition of lipofuscin pigment in the cells, due to which, during histology, the heart muscle changes color to brown-red, and the process is called “brown myocardial atrophy”. At the same time, dystrophic changes are found in other organs.

When does myocardial hypertrophy occur?

The most common cause of hypertrophic changes in the heart muscle is hypertension. Increased vascular resistance forces the heart to work against a high load.

The development of concentric hypertrophy is characterized by: the volume of the cavity of the left ventricle is preserved unchanged with a general increase in size.

Symptomatic hypertension in kidney disease, endocrine pathology are less common. Moderate thickening of the ventricular wall makes it difficult for blood vessels to grow into the depth of the mass, therefore it is accompanied by ischemia and a state of oxygen deficiency.

Cardiomyopathy - diseases with unknown causes, combine all possible mechanisms of myocardial damage from progressive dystrophy, leading to an increase in the ventricular cavity (dilated form), to severe hypertrophy (restrictive, hypertrophic).

A special variant of cardiomyopathy - spongy or non-compact myocardium of the left ventricle is congenital, often associated with other heart and vascular defects. Normally, non-compact myocardium makes up a certain proportion in the mass of the heart. It increases with hypertension, hypertrophic cardiomyopathy.

Pathology is detected only in adulthood by symptoms of heart failure, arrhythmias, and embolic complications. In a color Doppler study, an image is obtained in several projections, and the thickness of non-compacted areas is measured during systole, not diastole.

Myocardial damage during ischemia

In 90% of cases, atherosclerotic plaques are found in the coronary vessels with coronary disease, blocking the diameter of the feeding artery. A certain role is played by metabolic changes under the influence of disturbed nervous regulation - the accumulation of catecholamines.

With angina pectoris, the state of the myocardium can be characterized as forced "hibernation" (hibernation). The hibernating myocardium is an adaptive response to a lack of oxygen, adenosine triphosphate molecules, potassium ions, the main suppliers of calories. Occurs in local areas with prolonged circulatory disorders.

A balance is maintained between the decrease in contractility in accordance with impaired blood supply. At the same time, myocyte cells are quite viable and can fully recover with improved nutrition.

“Stunned myocardium” is a modern term that characterizes the state of the heart muscle after the restoration of coronary circulation in the area of the heart. Cells accumulate energy for several more days, contractility is impaired during this period. It should be distinguished from the phrase "myocardial remodeling", which means actual changes in myocytes under the influence of pathological causes.

How does the myocardium change in coronary artery thrombosis?

Prolonged spasm or blockage of the coronary arteries causes necrosis of the part of the muscle that they supply with blood. If this process is slow, the collateral vessels will take over the "work" and prevent necrosis.

The focus of infarction is located in the region of the apex, anterior, posterior and lateral wall of the left ventricle. Rarely captures the septum and the right ventricle. Necrosis in the lower wall occurs with blockage of the right coronary artery.

If the clinical manifestations and the ECG pattern converge in confirming the form of the disease, then the diagnosis can be confident and combined treatment can be used. But there are cases that require confirmation of the doctor's opinion, primarily with the help of accurate, undeniable markers of myocardial necrosis. As a rule, diagnostics is based on the quantitative determination of decay products, enzymes, more or less specific to necrotic tissues.

Can necrosis be confirmed by laboratory methods?

The development of modern biochemical diagnostics of infarction has made it possible to identify standard markers of myocardial necrosis for early and late manifestations of infarction.

Early markers include:

Myoglobin - increases in the first 2 hours, the optimal use of the indicator to monitor the effectiveness of fibrinolytic therapy.
Creatine phosphokinase (CPK) - a fraction from the heart muscles is only 3% of the total mass, so if it is not possible to determine only this part of the enzyme, the test has no diagnostic value. With myocardial necrosis, it rises on the second or third day. An increase in the indicator is possible with renal failure, hypothyroidism, and oncological diseases.
Cardiac type of protein that binds fatty acids - in addition to the myocardium, it is present in the aortic wall, diaphragm. Considered as the most specific indicator.

Late markers are:

Lactate dehydrogenase, the first isoenzyme, reaches its highest level by the sixth or seventh day, then decreases. The test is considered low specific.
Aspartate aminotransferase - reaches a maximum by the 36th hour. Due to low specificity, it is only used in combination with other tests.
Cardiac troponins - remain in the blood for up to two weeks. They are considered the most specific indicator of necrosis and are recommended by international diagnostic standards.

The given data on changes in the myocardium are confirmed by anatomical, histological and functional studies of the heart. Their clinical significance makes it possible to timely identify and assess the degree of myocyte destruction, the possibility of their recovery, and monitor the effectiveness of treatment.

Norms in ultrasound for heart chambers

The mass of the myocardium of the left ventricle: men -g, women -g.

Left ventricular myocardial mass index (in the form is often referred to as LVMI): men g / m2, women g / m2.

End-diastolic volume (EDV) of the left ventricle (the volume of the ventricle that it has at rest): men - 112 ± 27 (65-193) ml, women 89 ± 20 (59-136) ml

End-diastolic size (EDD) of the left ventricle (the size of the ventricle in centimeters, which it has at rest): 4.6 - 5.7 cm

The end systolic size (SSR) of the left ventricle (the size of the ventricle that it has during contraction): 3.1 - 4.3 cm

Wall thickness in diastole (outside the contractions of the heart): 1.1 cm

Stroke volume (the amount of blood that is ejected by the left ventricle in one contraction): ml.

Wall thickness: 5ml

Size index 0.75-1.25 cm/m2

Diastolic size (size at rest) 0.95-2.05 cm

Parameters of the interventricular septum

Thickness at rest (diastolic thickness): 0.75-1.1 cm

Excursion (moving from side to side during heart contractions): 0.5-0.95 cm. An increase in this indicator is observed, for example, with some heart defects.

Size: 1.85-3.3 cm

Size index: 1.45 - 2.9 cm/m2.

Norms in ultrasound for heart valves

The term "stenosis" refers to the narrowing of the opening of the valve, in which the upper chamber of the heart hardly pumps blood through it and may undergo hypertrophy, which we discussed in the previous section.

Insufficiency is the opposite state. If the valve leaflets, which normally prevent the backflow of blood, for some reason cease to perform their functions, the blood that has passed from one chamber of the heart to another partially returns back, reducing the efficiency of the organ.

Depending on the severity of the violations, stenosis and insufficiency can be 1,2 or 3 degrees. The higher the degree, the more serious the pathology.

Norms in ultrasound for the pericardium

The most common pathology of the pericardium is an inflammatory process, or pericarditis. In pericarditis, adhesions can form between the pericardial sac and the heart and fluid can accumulate. Normally, 100 ml indicates a small accumulation, and more than 500 ml indicates a significant accumulation of fluid, which can lead to difficulty in the full functioning of the heart and its compression ...

To master the specialty of a cardiologist, a person must first study at a university for 6 years, and then study cardiology separately for at least a year. A qualified doctor has all the necessary knowledge, thanks to which he can not only easily decipher the conclusion to an ultrasound of the heart, but also make a diagnosis based on it and prescribe treatment. For this reason, the interpretation of the results of such a complex study as ECHO-cardiography should be provided to a specialized specialist, and not try to do it on your own, long and unsuccessfully “poking around” in the numbers and trying to understand what these or those indicators mean. This will save you a lot of time and nerves, since you will not have to worry about your probably disappointing and, even more likely, wrong conclusions about your health.

The average value of the mass index of the left ventricular myocardium is 71 g/m2 in men and 62 g/m2 in women. The upper limit of this index is 94 and 89 g/m2, respectively.

The causes and mechanism of changes in the mass of the left ventricle in various diseases are still poorly understood.

Formula

The mass of the myocardium of the left ventricle (calculation) is determined by the following formula:

MI - myocardial mass index is determined by the formula:

MI=M/H2.7 or MI=M/S where

M is the mass of the myocardium of the left ventricle (in g);
H - height (in m);
S is the surface area of the body (in m2).

Causes

Causes of left ventricular hypertrophy include:

arterial hypertension;
various heart defects;
cardiomyopathy and cardiomegaly.

The mass of the myocardium of the left ventricle in 90% of patients with arterial hypertension exceeds the norm. Often hypertrophy develops with mitral valve insufficiency or with aortic defects.

The reasons why myocardial mass may exceed the norm are divided into:

Stages and symptoms

In the process of increasing the mass of the myocardium, three stages are distinguished:

compensation period;
subcompensation period;
decompensation period.

Consequences of left ventricular myocardial hypertrophy

Cardiac hypertrophy (increased mass of the myocardium of the left ventricle) increases the risk of developing cardiovascular disease and can lead to premature death.

Treatment

The method of treating left ventricular myocardial hypertrophy depends on the cause that caused the development of this pathology. If necessary, surgery may be prescribed.

Myocardial mass index

<0,001) (ММЛЖ, гр = 1,04×[(КДР+МЖП+ЗСЛЖ) 3 -КДР 3 ]-13,6) .

<0,001), переоценивала наличие ГЛЖ лишь на 6%, а чувствительность у пациентов с ГЛЖ (масса миокарда при аутопсии ><0,001), но систематически переоценивала наличие ГЛЖ (в среднем на 25%), что было устранено введением скорректированного уравнения (формула ASE): ММЛЖ=0,8×(ММЛЖ-кубическая формула)+0,6 гр. Однако, при её использовании наблюдалась недооценка ММЛЖ при аутопсии в пределах 30% .

<150 гр,гр - умеренной, а >

<90 гр/м она составила 4,7% против 12,2% при ИММЛЖ ≥140 гр/м, у женщин - 4,1% и 16,1% соответственно . Наблюдался рост ССЗ при более высокой ММЛЖ у мужчин в 2,6, а у женщин - в 3,9 раза, что доказывает прогностическую значимость и важность правильной оценки массы миокарда, поиска более точных диагностических критериев ГМЛЖ для раннего её выявления.

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

<0,001)

All methods except dependent

Bibliographic link

URL: http://science-education.ru/ru/article/view?id=23603 (date of access: 03/10/2018).

candidates and doctors of sciences

Modern problems of science and education

Myocardial mass: essence, norm, calculation and index, as it says

What is myocardial mass and how to estimate it correctly? This question is most often asked by patients who have undergone echocardiography and found, among other parameters, heart muscle mass and mass index.

Myocardial mass is the weight of the heart muscle, expressed in grams and calculated from ultrasound data. This value characterizes many pathological processes, and its change, usually upward, may indicate an unfavorable prognosis for the course of the pathology and an increased risk of serious complications.

The increase in myocardial mass is based on hypertrophy, that is, thickening, which characterizes the structural restructuring in the heart muscle, which forces doctors not only to conduct dynamic monitoring, but also to switch to active treatment tactics.

Modern recommendations regarding the therapy and diagnosis of various pathologies of the heart indicate that the mass of the myocardium of the left ventricle (LV) is not only possible, but also necessary to control, and for this, periodic ultrasound examinations of the heart are included in the protocols for managing patients with a risk of cardiac hypertrophy.

The norm of myocardial mass for men, on average, is considered to be in the range of r, for women - r.

The correct interpretation of echocardiography indicators still remains a serious problem, because it is necessary to correlate the instrumentally obtained data with a specific patient and establish whether there is already hypertrophy or some deviation from the norm can be considered a physiological feature.

To a certain extent, the mass of the myocardium can be considered a subjective indicator, because the same result for people of different heights, weights and genders can be regarded differently. For example, an indicator of myocardial mass in a large man involved in weightlifting will normally be excessive for a fragile girl of short stature who is not keen on going to the gym.

It has been established that myocardial mass has a close relationship with the size of the body of the subject and the level of physical activity, which must be taken into account when interpreting the results, especially if the indicator is very slightly different from the norm.

How is the mass of the myocardium of the left ventricle calculated at home?

The principle of calculating the mass of the LV myocardium

Causes affecting the deviation of the LV mass index of the myocardium from the norm

In most cases, the left ventricle and the myocardium as a whole increase under the influence of certain pathologies that provoke their significant overload of the heart:

valve defects;
cardiomyopathy;
arterial hypertension;
myocardial dystrophy.

Methods for calculating the mass of the left ventricle of the myocardium

The very norm of the myocardial mass index is calculated in many ways, but today medicine uses only the two most effective formulas: ASE and PC, which include the following data:

the thickness of the heart muscle between the right and left ventricles;
the thickness of the posterior cavity of the left ventricle (this indicator is measured in two stages: when the organ is completely filled with blood and when it is emptied);
end-diastolic dimensions of the left ventricle.

So, in order to determine the mass index of the left ventricle, it is initially required to scan the heart and myocardium, and substitute the resulting sizes of these organs into the following formula:

The abbreviations in this formula have the following designations:

IVS - the width of the septum between the ventricles, expressed in cm;
EDD - LV end-diastolic size;
ZLVZh - an indicator of the thickness of the posterior cavity of the left ventricle, expressed in cm.

Depending on who the patient is (male or female), the norm of the myocardial mass index will be slightly different. This difference looks like this:

If the patient is a man, then the norm for him will be from 135 to 182 grams;
If the patient is a woman, then for her the norm ranges from 95 to 141 grams.

With an overestimated indicator, it can be assumed that hypertrophy is rapidly developing in the patient's body, requiring urgent medical intervention.

Calculation of myocardial mass depending on the weight and height of the patient

As for the calculation of the ratio of myocardial mass to height and body weight, it is performed strictly according to the following formula:

The abbreviation of this formula is deciphered as follows:

M is the weight of the muscle, expressed in grams;
P is the patient's height;
P - the area of the patient's body, expressed in square meters.

Calculation of the mass of the myocardium of the left ventricle

Calculation of the mass of the myocardium of the left ventricle is carried out in the diagnostic study of the heart. The resulting value characterizes the internal state of the heart chamber. These measurements are studied in order to identify pathological disorders in its structure, to assess the ability to perform the main function. The task of the myocardium of the left ventricle is to perform rhythmic contractions that push blood under high pressure into the aorta. It is vital for continuous blood supply to the whole organism.

Norm indicators

The weight of the heart muscle is measured in grams and calculated according to the formula, the terms of which are obtained from echocardiography. Particular attention is focused on the state of the left ventricle. This is due to its significant functional load and greater susceptibility to change than the right one.

There is an established norm for the mass of the myocardium of the left ventricle. Its boundaries change depending on the gender of the patient, which is displayed in the table:

The data obtained during the instrumental examination must be correlated with the weight, physique and physical activity of a particular person.

This is necessary to explain possible deviations from the norm. Patient parameters, occupation, age, previous surgery or heart disease play a role in determining the cause of myocardial changes.

The heart muscle mass of a fragile woman differs from the indicator of a man's athletic physique, and this makes up the range of normative parameters.

Taking into account the height and weight characteristics of the patient, the mass index of the myocardium of the left ventricle is calculated, its norm is given in the table:

Mass and myocardial index are two diagnostic parameters that reflect the internal state of the heart and indicate the risk of circulatory disorders.

Hypertrophy

The thickness of the myocardium of the left ventricle is normally measured when it is relaxed, and is 1.1 cm. This indicator is not always saved. If it is elevated, then myocardial hypertrophy on the left is ascertained. This indicates excessive work of the heart muscle and can be of two types:

Physiological (growth of muscle mass under the influence of intense training);
pathological (enlargement of the heart muscle as a result of the development of the disease).

If the wall thickness of the left ventricle is from 1.2 to 1.4 centimeters, slight hypertrophy is recorded. This condition does not yet indicate pathology and can be detected during a medical examination of athletes. With intensive training, there is an increase in skeletal muscles and at the same time myocardial muscles. In this case, you need to monitor changes in cardiac muscle tissue using regular echocardiography. The risk of transition of physiological hypertrophy into a pathological form is very high. Thus, sports can harm health.

When the heart muscle changes up to two centimeters, the states of medium and significant hypertrophy are considered. They are characterized by the appearance of shortness of breath, a feeling of lack of air, pain in the heart, a violation of its rhythm and increased fatigue. Timely detected this change in the myocardium is amenable to medical correction.

An increase over 2 centimeters is diagnosed as high degree hypertrophy.

This stage of myocardial pathology is life-threatening due to its complications. The treatment method is selected according to the individual situation.

The principle of determining the mass

The definition of myocardial mass is calculated using the numbers obtained in the process of echocardiography. For the accuracy and objectivity of the evaluation of measurements, they are carried out in a combination of modes, comparing two- and three-dimensional images. The data is supplemented by the results of Doppler studies and indicators of ultrasound scanners, which are capable of displaying a life-size projection of the heart on the monitor screen.

Calculation of myocardial mass can be done in several ways. Preference is given to the two formulas ASE and PC, in which the following indicators are used:

the thickness of the muscular septum separating the cardiac ventricles;
directly the thickness of the posterior wall of the left chamber in a calm state, until the moment of its contraction;
full size of the relaxed left ventricle.

Interpretations of values obtained from echocardiography should be considered by an experienced specialist in functional diagnostics. Evaluating the results, he will note that the ASE formula represents the left ventricle along with the endocardium (the membrane of the heart that lines the chambers). This may cause distortion of its thickness measurement.

Formula

All measurements are taken in centimeters. Each abbreviation means:

You can measure the myocardial index using one of the formulas:

The meanings of the accepted abbreviations mean:

In measurements, the indicator of the area of \u200b\u200bthe test is used, because it is a more accurate value than body weight. This is due to the limitation of dependence on excessive amounts of adipose tissue. The surface area is calculated according to a fixed formula, where the parameters change according to the age of the patient.

The myocardial index is most indicative in pediatrics. This is due to the fact that the height of an adult remains unchanged during calculations over several years of the survey. The growth of the child is constantly changing, thanks to which it is possible to accurately track pathologies in cardiac parameters.

Myocardial mass index

Sinus bradyarrhythmia
diastolic dysfunction
Atrial fibrillation
Hypertension syndrome
myocardial infarction

Reasons for the deviation of the mass and mass index of the heart from normal numbers

The mass of the myocardium is increased in pathological processes leading to its overload:

Arterial hypertension;
valve defects;
Cardiomyopathy and myocardial dystrophy.

An increase in the mass of muscle tissue also occurs normally - with enhanced physical training, when intense sports cause an increase not only in skeletal muscles, but also in the myocardium, which provides the organs and tissues of the trainee with oxygen-rich blood.

Athletes, however, run the risk of eventually moving into the category of people with myocardial hypertrophy, which under certain conditions can become pathological. When the thickness of the heart muscle becomes greater than the coronary arteries can supply blood, there is a risk of heart failure. It is with this phenomenon that sudden death in well-trained and apparently quite healthy people is most often associated.

Thus, an increase in myocardial mass, as a rule, indicates a high load on the heart, whether during sports training or pathological conditions, but regardless of the cause, cardiac muscle hypertrophy deserves close attention.

Methods for calculating myocardial mass and mass index

The calculation of myocardial mass and its index is based on echocardiography data in different modes, while the doctor must use all the possibilities of instrumental examination, correlating two- and three-dimensional images with Doppler data and using additional capabilities of ultrasound scanners.

Since, from a practical point of view, the large mass of the left ventricle, as the most functionally loaded and prone to hypertrophy, plays the greatest role, the calculation of the mass and mass index for this particular chamber of the heart will be discussed below.

The calculation of the myocardial mass index and the actual mass in different years was carried out using a variety of formulas due to the individual features of the geometry of the heart chambers in the subjects, which make it difficult to create a standard calculation system. On the other hand, a large number of formulas complicated the formulation of the criteria for hypertrophy of a particular part of the heart, so the conclusions regarding its presence in the same patient could differ with different methods of assessing EchoCG data.

Today, the situation has improved somewhat, largely due to more modern ultrasound diagnostic devices, which allow only minor errors, but there are still several calculation formulas for determining the mass of the myocardium of the left ventricle (LV). The most accurate of them are the two proposed by the American Society of Echocardiography (ASE) and the Penn Convention (PC), which take into account:

The thickness of the heart muscle in the septum between the ventricles;
The thickness of the posterior LV wall at the end of the period of filling with blood and before the next contraction;
End-diastolic size (EDD) of the left ventricle.

In the first formula (ASE), the thickness of the left ventricle includes the thickness of the endocardium, in the second similar calculation system (PC) it is not taken into account, so the formula used must be indicated as a result of the study, since the interpretation of the data may be erroneous.

Both calculation formulas are not distinguished by absolute reliability and the results obtained from them often differ from those at the autopsy, however, of all the proposed ones, they are the most accurate.

The formula for determining the mass of the myocardium looks like this:

0.8 x (1.04 x (IVS + KDR + ZSLZh) x 3 - KDR x 3) + 0.6, where IVS is the width of the interventricular septum in centimeters, KDR is the end-diastolic size, ZSLZh is the thickness of the posterior LV wall in centimeters.

The norm of this indicator differs depending on gender. Among men, the range d will be normal, for women - r.

In addition to the objectivity of assessing the mass of the myocardium, there is another problem: the need to identify clear indexing criteria to determine the presence and degree of hypertrophy, because the mass has a direct relationship with the size of the body of the subject.

The myocardial mass index is a value that takes into account the height and weight parameters of the patient, correlating the mass of the myocardium to the body surface area or height. It is worth noting that the mass index, which takes into account growth, is more applicable in pediatric practice. In adults, growth is constant and therefore does not have such an impact on the calculation of the parameters of the heart muscle, and possibly even leads to erroneous conclusions.

The mass index is calculated as follows:

IM=M/H2.7 or M/P, where M is the muscle mass in grams, P is the height of the subject, P is the body surface area, m2.

Domestic experts adhere to a single accepted figure for the maximum mass index of the left ventricular myocardium - 110 g/m2 for women and 134 g/m2 for the male population. With diagnosed hypertension, this parameter is reduced in men to 125. If the index exceeds the specified maximum allowable values, then we are talking about the presence of hypertrophy.

The form of an echocardiographic study usually indicates lower average standards for the mass index relative to the body surface: g / m2 in men and g / m2 in women (different formulas are used, therefore, the indicators may differ). These limits characterize the norm.

If the mass of the myocardium is correlated with the length and area of the body, then the range of variation in the norm of the indicator will be quite high: for men and women when taking into account body area, for men and women when indexed by height.

Given the above-described features of the calculations and the resulting figures, left ventricular hypertrophy cannot be accurately excluded, even if the mass index falls within the range of normal values. Moreover, many people have a normal index, while they have already established the presence of initial or moderately severe cardiac hypertrophy.

Thus, the mass of the myocardium and the mass index are parameters that make it possible to judge the risk or presence of hypertrophy of the heart muscle. Interpretation of the results of echocardiography is a difficult task, which is within the power of a specialist with sufficient knowledge in the field of functional diagnostics. In this regard, independent conclusions of patients are far from always correct, therefore, it is better to go to a doctor to decipher the result in order to exclude false conclusions.

Individual differences in LV geometry prevent the creation of its universal mathematical model even in the absence of local violations of the LV structure and the approximation of its shape to an ellipse, which gave rise to a large number of formulas, and, consequently, criteria for determining LVH, which results in different conclusions about the presence of hypertrophy in one and the same patient.

The correction of LVML to BSA, calculated according to the Du Bois formula, is more often used, but this standardization is imperfect, because it underestimates LVML in people with obesity.

The above ambiguous ideas about the normal values of LVMI, LVMI and LVH criteria are presented in Table 1.

LVMI as a criterion for LVLV with and without gender

D. Levy, Framingham Research, 1987

J.K. Galy, 1992

I.W. Hammond, 1986

E.Aberget, 1995

De G. Simone, 1994

J.J. Mahn, 2014

Recommendations for chamber quantification: Guidelines, 2005

Not gender sensitive

M.J. Koren, 1981

De G. Simone, 1995

Correspondence of the incidence of LVH according to different methods of its determination

(performance ratio (KFR) in %; p<0,001)

All methods except dependent

Onishchenko Alexander Leonidovich, Doctor of Medical Sciences, Professor, Vice-Rector for Research, SBEI DPO NGIUV MOH of Russia, Novokuznetsk;

Bibliographic link

Zadorozhnaya M.P., Razumov V.V. DISPUTE ISSUES OF ECHOCARDIOGRAPHIC DETERMINATION OF LEFT VENTRICULAR MYOCARDIAL MASS AND ITS HYPERTROPHY (ANALYTICAL REVIEW AND OWN OBSERVATIONS) // Modern problems of science and education. - 2015. - No. 6.;

URL: https://science-education.ru/ru/article/view?id=23603 (date of access: 09/02/2017).

The field of activity (technology) to which the described invention belongs

The know-how of the development, namely, this invention of the author belongs to the field of medicine and can be used to diagnose left ventricular myocardial hypertrophy.

DETAILED DESCRIPTION OF THE INVENTION

In cardiology practice, special attention should be paid to the diagnosis of left ventricular hypertrophy. This is due to the fact that, as shown by numerous studies, left ventricular myocardial hypertrophy is a more rigorous predictor of cardiovascular complications and mortality than blood pressure and other risk factors [Florya V.G. The role of left ventricular remodeling in the pathogenesis of chronic circulatory failure. // Cardiology, 1997, No. 5, p.63-69; Yurenev A.P., Gerashchenko Yu.S., Dubov P.B. On the prognosis of the course of the disease in hypertensive patients with coronary insufficiency. // Ter. arch. 1994; 66:4:9-11; Bikkina M., Levy D., Evans J.S et al. Left ventricular mass and risk of strok in an elderly cohort: the Framingham Heart Study. JAMA, 1994; 272; 33-36; Devereux R.B. Left ventricular geometry, pathophysiology and prognosis. J Am Coll Cardiol, 1995; 25:]. Even a small change in the mass of the left ventricle within normal values can serve as a prognostic sign of an increase in cardiovascular risk.

An increase in the mass of the left ventricle is a common final way of many adverse cardiovascular outcomes [Florya V.G. The role of left ventricular remodeling in the pathogenesis of chronic circulatory failure. // Cardiology, 1997, No. 5, p.63-69; Devereux R.B. Left ventricular geometry, pathophysiology and prognosis. J Am Coil Cardiol, 1995; 25:].

According to the Framingham Study, individuals 35 to 64 years of age with electrocardiographic evidence of LVH are 3 to 6 times more likely to develop cardiovascular disease than those without LVH. After the appearance of ECG signs of LVH, 35% of men and 20% of women die within 5 years; in older age groups, 5-year mortality among men and women reaches 50 and 35%, respectively.

Due to the important prognostic value, clear criteria are needed to diagnose LVH as early as possible and to dynamically monitor the process of cardiac remodeling. Currently, there are several ways to diagnose left ventricular myocardial hypertrophy.

The simplest and most accessible method is electrocardiography. There are the following ECG criteria for left ventricular hypertrophy:

Sokolov-Lyon index (SV1+RV5/RV6>35 mm) (sensitivity 22%, specificity 100%)

Cornell voltage index RaVL+SV3 >28 mm in men and >20 mm in women (sensitivity 42%, specificity 96%)

RaVL>11 mm (sensitivity 11%, specificity 96%). [Prevention, diagnosis and treatment of primary arterial hypertension in the Russian Federation. // Clinical pharmacology and therapy 2000, No. 9 (3), p.5-30].

Despite the high specificity of the electrocardiographic method (96-100%), it has a low sensitivity (22-42%), which does not allow it to be effectively used to solve the tasks.

From the patent literature, another method for diagnosing ventricular myocardial hypertrophy is known (ed. certificate No. class. A 61 B 5/02), including an electrocardiographic examination of the patient in conventional leads, characterized in that in order to increase the accuracy of determining the predominance of right or left ventricular myocardial hypertrophy hearts with their combined hypertrophy additionally determine the ratio of the amplitude of the R wave to the sum of the amplitudes of the Q, R, S waves in standard leads, the ratio of the amplitude of the R wave to the sum of the amplitudes of the R and S teeth in the chest leads V1 and V2, V4 and V5, summarize the obtained values in pairs taking into account their direction and value in leads III, V1, V2, V4 with the sign /+/, and in leads I, V5 - with the sign /-/ and the hypertrophy index (HI) is determined by the formula: IG=(R/(Q +R+S)III-R/(Q+R+S)I)+(R/(R+S)V1+R/(R+S)V2)+(R/(R+S)V4-R /(R+S)V5), where Q, R, S are the amplitudes of the ECG QRS complex teeth in leads I, III, V1, V2, V4, V5, mm left ventricular pertrophy with combined ventricular hypertrophy of the heart. This method allows only to determine the predominance of hypertrophy of one of the ventricles and cannot be used for its early diagnosis. The method is based on electrocardiographic criteria and, therefore, its sensitivity is insufficient.

The diagnosis of LVH can be established as a result of a pathoanatomical study (normally, the mass of the myocardium is 1/215 of the body weight in men and 1/250 of the body weight in women [Human Anatomy. Gain M.G., N.K. Lysenkov, V. I. Bushkovich, St. Petersburg, Hippocrates, 1997]), but it can only be performed posthumously, which significantly limits the possibilities of its application.

Currently, echocardiographic criteria are most often used to diagnose myocardial hypertrophy. The echocardiographic research method allows obtaining clear data, on the basis of which changes in the structure and function of the heart are assessed. In the diagnosis of LVH, this method is more sensitive than electrocardiography. Left ventricular myocardial mass, which can be calculated from echocardiographic data, is a more reliable predictor of morbidity and mortality.

Usually, echocardiography determines:

The thickness of the interventricular septum (IVS)

The thickness of the posterior wall of the left ventricle (ZSLZh),

Hypertrophy is spoken of in those cases when the IVS exceeds 10 mm, and the ZSLZh exceeds 11 mm [Strutynsky A.V. Echocardiogram: analysis and interpretation. // M., 2001], however, left ventricular hypertrophy can also be observed with normal values of the IVS and ZSLZH due to its dilation.

A more accurate echocardiographic sign of LVH is an increase in the mass of the left ventricular myocardium, which is calculated using the formula proposed by R.Devereux and N.Reichek:

where MMLZH - the mass of the myocardium of the left ventricle;

IVS - the thickness of the interventricular septum in diastole;

ZSLZh - the thickness of the posterior wall of the left ventricle in diastole;

The mass of the myocardium calculated in this way is not related to the constitutional features of the patient. That is why there is still no unity in understanding at what values of the mass of the myocardium of the left ventricle one can speak of LVH [Sidorenko B.A., Preobrazhensky D.V. Left ventricular hypertrophy: pathogenesis, diagnosis and possibility of regression under the influence of antihypertensive therapy. // Cardiology.; 5:80-85]. This drawback, on the one hand, significantly limits the use of the Devereux and Reichek formula in the diagnosis of myocardial hypertrophy proper in this patient, and on the other hand, does not allow the use of this indicator for epidemiological studies.

The mass of the myocardium largely depends on gender, anthropometric indicators of the human body [Human Anatomy. Weight gain M.G., N.K. Lysenkov, V.I. Bushkovich. SPb, Hippocrates, 1997], therefore, as a criterion for diagnosing LVH, the mass index of the left ventricular myocardium is used, calculated by the formula:

where IMM is the mass index of the myocardium of the left ventricle;

MMLV - mass of the myocardium of the left ventricle;

S is the surface area of the body.

The surface area of the body is calculated by the Dubois formula [Human Physiology in 2 volumes, ed. V.M. Pokrovsky and G.F. Korotko, M., Medicine, 2001 // V.2, p.119]:

S-m 0.425 h 0.725 71.84,

where m is the body weight;

The normal proportions of the human body, its organs and tissues, which are the basis for calculating the myocardial mass index, can change significantly under various pathological conditions. This is confirmed by the fact that different authors give different values of the mass index of the left ventricular myocardium as the lower limit for LVH in men and women [Sidorenko B.A., Preobrazhensky D.V. Left ventricular hypertrophy: pathogenesis, diagnosis and possibility of regression under the influence of antihypertensive therapy // Kardiologiya.; 5:80-85].

Myocardial mass index calculations are given in Tables 1-8.

When calculating the body surface area according to the Dubois formula, with an increase in body weight (with edema, obesity) by 25%, the body surface area will increase by about 10%, and with an increase in body weight by 50% - by about 19%. Accordingly, the decrease in the myocardial mass index (IMM) calculated using this formula will occur without changing the value of its real mass and morphological properties. Similarly, there is a formal increase in the myocardial mass index with a decrease in body weight (weight loss, dehydration of the body with vomiting, diarrhea, prescription of diuretics, etc.). In addition, it is impossible to focus on this indicator in persons who have lost limbs, with developmental anomalies, due to the fact that the body surface area, body weight and height in such people are related by other ratios.

With age, a person's height decreases by 5-7 cm due to an increase in the curvature of the spine and a decrease in the thickness of the intervertebral discs [Textbook of anatomy for medical students, ed. prof. Sapina M.R. in 2 volumes, M., Medicine, 1987, T.1], which leads to the inadequacy of the use of this method for diagnosing myocardial hypertrophy in the elderly and senile. In addition, human height changes even during the day by 2-4 cm [Zhigulev N.M., Badzgaradze Yu.D., Zhigulev S.N. Osteochondrosis of the spine: a guide for physicians. - St. Petersburg .. - Publishing House "Lan", 592 p.].

In connection with the above, the myocardial mass index calculated on the basis of body surface area is a very unstable indicator, the use of which for the diagnosis of myocardial hypertrophy in a number of cases gives false positive and false negative results. This makes it impossible to use the myocardial mass index for dynamic monitoring of patients when it is necessary to evaluate, for example, the effectiveness of the therapy or the degree of prognostic risk in a given patient with myocardial hypertrophy.

The objective of the present invention is to achieve an objective criterion that allows diagnosing left ventricular myocardial hypertrophy, which could be used with equal success both for single use and for dynamic monitoring of a specific patient, as well as for epidemiological studies.

The solution of the problem is achieved by calculating the myocardial mass index based on the results of echocardiographic studies and anthropometric measurements. The method is carried out as follows.

The patient undergoes an echocardiographic study to determine the thickness of the interventricular septum, the thickness of the posterior wall of the left ventricle and the final diastolic size. After that, the mass of the myocardium of the left ventricle is calculated according to the formula:

where IVS is the thickness of the interventricular septum in diastole;

ZS - thickness of the posterior wall of the left ventricle in diastole;

KDR - end diastolic size of the left ventricle.

Then the patient is given anthropometric measurements (in cm):

a) the width of the forearm at the level of the styloid process of the ulna, d;

b) circumference of the forearm at the level of the styloid process of the ulna, p;

c) distance from the styloid process of the ulna to the apex of the olecranon of the ulna, L.

After that, the bone coefficient k is calculated by the formula:

It closely correlates (correlation coefficient r = 0.91) with body surface area in healthy people with normal body weight, does not change with a decrease or increase in unstable indicators that determine body surface area. Then calculate the mass index of the myocardium of the left ventricle (H i) according to the formula:

The criterion for the presence of hypertrophy of the myocardium of the left ventricle is the value of H i more than 0.6.

We propose an indicator that links the mass of the myocardium to the dimensions of the bones of the forearm, which are more stable than height and weight, which determine the surface area of the body.

The formation of the skeleton of the forearm ends by the age of 25, and the established proportions remain without significant changes until the end of a person's life [Textbook of anatomy for students of medical institutes, ed. prof. Sapina M.R. in 2 volumes, M., Medicine, 1987, T.1]. Pathological changes in soft tissues (edema, dehydration, excessive development of subcutaneous adipose tissue, weight loss) do not significantly affect the size of the bones.

The use of the ratio of myocardial mass to the indicator associated with the size of the bones of the skeleton makes it possible to exclude incorrect changes in the myocardial mass index that occur in the conditions described above. This makes it possible to monitor the dynamics of myocardial hypertrophy, for example, during therapeutic measures accompanied by a change in body weight. In addition, this makes it possible to adequately diagnose myocardial hypertrophy in patients without limbs (provided that at least one forearm is present), with developmental anomalies, etc.

The method can also be used to control myocardial hypertrophy in patients in cases where it is difficult to determine their height and weight (for example, in unconscious patients in skeletal traction, in a plaster cast, etc.).

Another advantage of our method is that the dynamics of myocardial mass can be assessed throughout the life of the patient and, therefore, be used in epidemiological studies. This is possible due to the fact that the value of the proposed bone coefficient k and the associated myocardial mass index will practically not change with age, while the body surface area may vary and lead to an incorrect change in the conventional mass index of the left ventricular myocardium.

Patient C, aged 55, diagnosis: Hypertension II st. ischemic heart disease. Angina pectoris II FC. CHF I st.

Upon admission to the hospital, the patient underwent electrocardiographic, echocardiographic and anthropometric studies.

The results of electrocardiography do not give grounds to diagnose myocardial hypertrophy in a patient. When using the proposed index H i, the diagnosis of hypertrophy is obvious.

Patient A, 78 years old, diagnosis: ischemic heart disease. Angina pectoris III FC. Hypertension II stage. CHF II B. Diabetes mellitus type II, moderate to severe course. Obesity III Art. Upon admission to the hospital, an echocardiographic study and anthropometric measurements were performed, the following results were obtained:

It can be seen from the tables that using the generally accepted IMM, we cannot diagnose myocardial hypertrophy, because this patient is overweight and we get a deliberately false result (BMI = 129.62) - the absence of hypertrophy. Using the new criterion H i (H i >0.6), we diagnose myocardial hypertrophy.

After the therapy, the patient's body weight changed (due to the disappearance of edema and a decrease in subcutaneous fat), after a second study, the following results were obtained:

Thus, based on the IMM, we can make a false conclusion that during the therapy the patient developed myocardial hypertrophy. (BMI increased from 129.62 to 140.59). If, however, the H i criterion is used as a criterion for left ventricular myocardial hypertrophy, it becomes obvious that the patient's real myocardial hypertrophy has not undergone any changes (H i remained equal to 0.62).

Patient B., aged 55, missing both lower limbs, diagnosis: Type II diabetes mellitus, severe course. Diabetic angiopathy of n / extremities. Stumps of both thighs. When carrying out the studies described above, it was obtained:

The use of IMM in this case is impossible, because. the calculated surface area does not reflect the normal proportions of the body and we get an incorrect result (BMI = 204.80), and therefore, we diagnose left ventricular myocardial hypertrophy even in its absence, using our method, we reject the diagnosis of hypertrophy.

Thus, the proposed method for diagnosing left ventricular myocardial hypertrophy using bone coefficient k and myocardial mass index H i allows you to adequately assess the presence or absence of left ventricular myocardial hypertrophy, conduct dynamic monitoring of a particular patient, and also makes it possible to use the data obtained in epidemiological studies .

Claim

A method for diagnosing left ventricular myocardial hypertrophy, which consists in the fact that the patient undergoes an echocardiographic study to determine the final diastolic size, the thickness of the myocardium of the posterior wall of the left ventricle in diastole, the thickness of the myocardium of the interventricular septum in diastole, the mass of the myocardium of the left ventricle according to the Devereux formula with the calculation of the myocardial mass index left ventricle, characterized in that the patient is additionally measured the width of the forearm between its lateral surfaces at the level of the styloid process of the ulna, the circumference of the forearm at the level of the styloid process of the ulna, the length of the ulna from the styloid process to the top of the olecranon process of the ulna, and based on the data obtained calculate the bone coefficient k:

where d is the width of the forearm at the level of the styloid process of the ulna;

p - circumference of the forearm at the level of the styloid process of the ulna;

L - the length of the ulna from the styloid process to the top of the olecranon of the ulna,

then the myocardial mass index is calculated taking into account the bone coefficient H i according to the formula:

with values greater than 0.6, left ventricular myocardial hypertrophy is diagnosed.

Inventor's name:

Name of the patentee: Kivva Vladimir Nikolaevich (RU); Maklyakov Yuri Stepanovich (RU); Pshenichkin Konstantin Ivanovich (RU); Slavskaya Natalya Alexandrovna (RU); Morozova Elena Aleksandrovna (RU); Ryabov Andrey Anatolievich (RU); Abramova Tatyana Nikolaevna (RU)

Postal address for correspondence:, Rostov-on-Don, st. Taganrog highway, 126/1, apt. 22, V.N. Kivve

Patent start date: 2004.12.23

Modern recommendations regarding the therapy and diagnosis of various pathologies of the heart indicate that the mass of the myocardium of the left ventricle (LV) is not only possible, but also necessary to control, and for this, periodic ultrasound examinations of the heart are included in the protocols for managing patients with a risk of cardiac hypertrophy.

The norm of myocardial mass for men, on average, is considered to be in the range of 135 - 182 g, for women - 95 - 141 g.

Reasons for the deviation of the mass and mass index of the heart from normal numbers

The mass of the myocardium is increased in pathological processes leading to its overload:

Thus, an increase in myocardial mass, as a rule, indicates a high load on the heart, whether during sports training or pathological conditions, but regardless of the cause, cardiac muscle hypertrophy deserves close attention.

Methods for calculating myocardial mass and mass index

The thickness of the heart muscle in the septum between the ventricles;
The thickness of the posterior LV wall at the end of the period of filling with blood and before the next contraction;
End-diastolic size (EDD) of the left ventricle.

The formula for determining the mass of the myocardium looks like this:

0.8 x (1.04 x (MZHP + KDR + ZSLZH) x 3 - KDR x 3) + 0.6, where IVS is the width of the interventricular septum in centimeters, EDD is the end-diastolic size, ZSLZh is the thickness of the posterior wall of the left ventricle in centimeters.

The norm of this indicator differs depending on gender. Among men, the range of 135-182 g will be normal, for women - 95-141 g.

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The mass index is calculated as follows:

IM=M/N2.7 or M/P, where M is the muscle mass in grams, P is the height of the subject, P is the body surface area, m2.

The form of an echocardiographic study usually indicates lower average standards for the mass index relative to the body surface: 71-94 g / m2 for men and 71-89 g / m2 for women (different formulas are used, therefore, the indicators may differ). These limits characterize the norm.

If the mass of the myocardium is correlated with the length and area of the body, then the range of variation in the norm of the indicator will be quite high: 116-150 for men and 96-120 for women when taking into account body area, 48-50 for men and 45-47 for women when indexed by height .

Thus, myocardial mass and mass index are parameters that make it possible to judge the risk or presence of cardiac muscle hypertrophy. Interpretation of the results of echocardiography is a difficult task, which is within the power of a specialist with sufficient knowledge in the field of functional diagnostics. In this regard, independent conclusions of patients are far from always correct, therefore, it is better to go to a doctor to decipher the result in order to exclude false conclusions.

The modern method of hardware diagnostics - echocardiography or ultrasound of the heart, is based on the use of high-frequency sound waves. Through ultrasound, a medical specialist determines the cause of functional failures in the organ, reveals changes in the anatomical structure and histological structure of tissues, and determines anomalies in the vessels and valves of the heart.

The prerogative aspects of ultrasound diagnostics are:

no damage to the skin and penetration into the patient's body (non-invasiveness);
harmlessness. Ultrasonic waves are safe for health;
informative. Clear visualization of the heart allows you to accurately determine the pathology;
no contraindications to the use of the method;
the possibility of observing dynamic processes;
relatively low cost of research;
little time spent on the procedure.

Ultrasound of the heart is performed by the doctor of the radiology department in the direction and recommendations of the cardiologist. If you wish, you can go through the procedure yourself.

Purpose of the study

The indications for the procedure are the patient's complaints about certain symptoms:

systematic pain in the chest;
breathing difficulties during physical activity;
heart rhythm disturbances (often rapid);
swelling of the extremities, not associated with kidney disease;
stable high blood pressure.

Indications for echocardiography in children

A study of newborns is performed with suspicion of developmental anomalies and with pathology diagnosed in the perinatal period. The following cases may be the reason to check the work of the heart in a child: loss of consciousness for a short time, unwillingness to suck milk from the chest for no apparent reason (colds, abdominal cramps), shortness of breath with shortness of breath without signs of SARS.

The list continues with systematically freezing hands and feet under normal temperature conditions, bluish coloration (cyanosis) in the area of the mouth, chin and nasolabial part of the face, rapid fatigue, pulsating veins in the right hypochondrium and neck, and developmental abnormalities. A pediatrician may also recommend that you undergo an examination if, when listening with a medical phonendoscope, an extraneous sound is detected during the contractile activity of the myocardium.

Children in puberty should undergo the procedure, as the body undergoes a sharp growth spurt, and the heart muscle may be delayed. In this case, ultrasound is focused on assessing the adequate development of the internal organs to the external data of a teenager.

Study parameters and possible diagnoses

With the use of ultrasound are installed:

dimensions of the heart, ventricles and atria;
thickness of the heart walls, tissue structure;
beat rhythm.

On the image, the doctor can fix the presence of scars, neoplasms, blood clots. Echocardiography informs about the state of the heart muscle (myocardium) and the outer connective tissue membrane of the heart (pericardium), examines the valve located between the left atrium and ventricle (mitral). Doppler ultrasound gives the doctor a complete picture of the state of the vessels, the degree of their blockage, the intensity and volume of blood flow.

Information about the health of the heart and vascular system, obtained during the study, allows the most accurate diagnosis of the following diseases:

impaired blood supply due to blockage of blood vessels (ischemia);
necrosis of part of the heart muscle (myocardial infarction, and pre-infarction stage);
stage of hypertension, hypotension;
a defect in the structure of the heart (malformation of a congenital or acquired nature);
clinical syndrome of chronic organ dysfunction (cardiac decompensation);
valve dysfunction;
failure of the heart rhythm (extrasystole, arrhythmia, angina pectoris, bradycardia);
inflammation of the tissue in the membranes of the heart (rheumatism);
damage to the heart muscle (myocarditis) of inflammatory etiology;
inflammation of the lining of the heart (pericarditis);
narrowing of the aortic lumen (stenosis);
a complex of symptoms of organ dysfunction (vegetovascular dystonia).

Decoding research results

Through the procedure of ultrasound of the heart, it is possible to analyze in detail the entire cardiac cycle - a period that consists of one contraction (systole) and one relaxation (diastole). Assuming a normal heart rate of about 75 beats per minute, the duration of the cardiac cycle should be 0.8 seconds.

Echocardiography indicators are deciphered sequentially. Each unit of the cardiac structure is described by a diagnostician in the study protocol. This protocol is not a document with a final conclusion. The diagnosis is made by a cardiologist after a detailed analysis and comparison of protocol data. Therefore, comparing the indicators of your ultrasound and the standards, you should not engage in self-diagnosis.

Normal ultrasound values are an average value. The results are influenced by the gender and age category of the patient. In men and women, the parameters of the mass of the myocardium (muscular tissue of the heart) of the left ventricle, the coefficient of the index of this mass, and the volume of the ventricle differ.

For children, there are separate norms for the size, weight, volume, and functionality of the heart. At the same time, they are different for boys and girls, for newborn babies and babies. In adolescents from the age of 14, the indicators are compared according to adult male and female standards.

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In the final protocol, the evaluation parameters are conditionally indicated by the initial letters of their full names.

Parameters and guidelines for pediatric echocardiography

Deciphering the ultrasound of the heart and the functions of the circulatory system of the newborn is as follows:

left atrium (LA) or atrial septal diameter in girls/boys: 11–16 mm/12–17 mm, respectively;
right ventricle (RV) in diameter: girls / boys - 5–23 mm / 6–14 mm;
the final size of the left ventricle during relaxation (diastole): dev./small. – 16–21 mm/17–22 mm. Abbreviation in the LV CDR protocol;
the final size of the left ventricle during contraction (systole) is the same for both sexes - 11–15 mm. In the protocol - LV CSR;
posterior wall of the left ventricle in thickness: dev./small. – 2–4 mm/3–4 mm. Abbreviation - TZSLZH;
intergastric septum in thickness: dev./small. – 2–5 mm/3–6 mm. (MZHP);
free wall of the pancreas - 0.2 cm–0.3 cm (in boys and girls);
ejection fraction, that is, part of the blood that is ejected from the ventricle into the vessels at the time of cardiac contraction - 65–75%. FB abbreviation;
blood flow in the pulmonary valve in terms of its speed is from 1.42 to 1.6 m/s.

Indicators of the size and function of the heart for the baby correspond to the following standards:

A planned ultrasound of the heart for babies is carried out for babies at the age of one month and one-year-old babies.

Adult Guidelines

Normal ultrasound in an adult should correspond to the following digital ranges:

mass of the LV myocardium (left ventricle): men / women - 135-182 g / 95-141 g, respectively;
LV myocardial mass index: male - from 71 to 94 g / m 2, female - from 71 to 89 g / m 2;
end diastolic size (EDD) / ESD (end systolic size): 46–57.1 mm / 31–43 mm, respectively;
LV wall thickness in relaxation (diastole) - up to 1.1 cm;
blood ejection during contraction (FB) - 55–60%;
the amount of blood pushed into the vessels - from 60 ml to 1/10 liter;
PZH size index - from 0.75 to 1.25 cm / m 2;
wall of the pancreas in thickness - up to ½ cm;
RV EDD: 0.95 cm–2.05 cm.

Normal ultrasound findings for IVS (gastric septum) and atria:

wall thickness in the diastolic phase - 7.5 mm–1.1 cm;
the maximum deviation at the systolic moment is 5 mm–9.5 mm.
end-diastolic volume of PP (right atrium) - from 20 ml to 1/10 liter;
dimensions of the LA (left atrium) - 18.5–33 mm;
LP size index - 1.45–2.9 cm / m 2.

The aortic opening normally ranges from 25 to 35 mm 2. A decrease in the index indicates stenosis. The heart valves should be free of neoplasms and deposits. Evaluation of the operation of the valves is carried out by comparing the size of the norm and possible deviations in four degrees: I - 2-3 mm; II - 3–6 mm; III - 6–9 mm; IV - over 9 mm. These indicators determine how many millimeters the valve sags when the valves close.

The outer layer of the heart (pericardium) in a healthy state does not have adhesions and does not contain fluid. The intensity of the movement of blood flows is determined during an additional ultrasound examination - Dopplerography.

The ECG reads the electrostatic activity of the heart rhythms and tissues of the heart. On ultrasound, the speed of blood circulation, the structure and size of the organ are evaluated. Ultrasound diagnostics, according to cardiologists, is a more reliable procedure for making the correct diagnosis.

The study of the physical parameters of the myocardium is very important in the diagnosis and further treatment of patients suffering from diseases of the cardiovascular system. Hypertrophy of the heart muscle is a dangerous syndrome that can lead to dangerous complications and death. Therefore, this problem is relevant at the present time and requires close consideration.

Characteristics of the myocardium and methods for their calculation

The myocardium is a muscular layer of the heart, which consists of mononuclear cells with a special transverse arrangement. This ensures extreme muscle strength and the ability to evenly distribute work throughout the heart. The interposition of cells according to the type of intercalated disks determines the unusual properties of the myocardium. These include excitability, contractility, conduction, relaxation, and automatism.

It is possible to assess whether the heart is healthy with the help of additional instrumental examinations. Normal indicators according to the results of ventricular myocardial echocardiography (one of the key methods for diagnosing the pathology of blood ejection) are as follows:

left ventricle (LV): myocardial mass - 135-182 g, 95-141 g; mass index (LVMI) - 71-94 g/m 2 , 71-84 g/m 2 in men and women, respectively;
right ventricle (RV): wall thickness - 3 mm; size index - 0.75-1.25 cm / m 2; the size of diastole at rest is 0.8-2.0 cm.

The left ventricle takes on a greater functional load than any other parts of the heart, respectively, more often subject to pathological changes. Therefore, we will consider its parameters in more detail.

The calculation of the mass of the myocardium of the left ventricle is obtained by making various calculations. The calculator processes numbers using special formulas. At the present stage, 2 forms of calculation are recognized as the most sensitive, which are recommended by the American Society of Echocardiography (ASE) and Penn Convention (PC). The difference between them is only in the inclusion of the thickness of the inner layer of the heart when using the first formula.

So, the formula for determining the mass of the myocardium is as follows:

0.8 x (1.04 x (MZHP + KDR + ZSLZH) x 3 - KDR x 3) + 0.6, where

MZHP- this is the interventricular septum in diastole;
KDR is the end-diastolic size of the left ventricle;
ZSLZh- this is the posterior wall of the left ventricle during the period of relaxation.

The norm of the mass of the myocardium of the left ventricle depends on gender. For men, this value is about 135-182 g. For women, these figures are lower and range from 95 to 141 g.

It has been scientifically proven that the weight of the myocardium is closely dependent on the size of the body (in particular, on the mass-height index). In this regard, a special index was introduced, which takes into account all the individual characteristics of the patient, even his age. There are two formulas to calculate it:

MI \u003d M / H2.7, where M is the mass of the LV myocardium in g; H - height in m. Used in pediatrics;
MI \u003d M / S, where M is the mass of the heart muscle in g; S - body surface area, m 2. Used for adults.

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