Hypertrophic cardiomyopathy in cats. Heart disease in cats. cardiomyopathy. gkmp and dkmp what is it

The most common heart condition in cats is hypertrophic cardiomyopathy (HCM). This is a pathology of the heart, accompanied by a pronounced thickening of the heart muscle (myocardium) and leading to the development of heart failure, up to and including death.

A distinctive feature of this disease is the insidious development of symptoms and difficulty in treatment for later stages.

The reasons for the development of the disease

The reasons for the development of this disease have not yet been sufficiently studied, but a number of studies have identified genetically inherited abnormalities that can lead to the development of HCM. At the same time, it has been proven that representatives of the following breeds are especially prone to this pathology: Maine Coon, Ragdoll, Sphynx, British and American Shorthair, Scottish Fold, Norwegian Forest cats and possibly some others.

The mechanisms of inheritance of this disease have not yet been fully understood, but it has been proven that, for example, in the Maine Coon breed, HCM is inherited in an autosomal dominant manner. At the same time, special tests (blood tests) are even widespread abroad for the presence of corresponding deviations in the genotype in cats of this breed. In Britain, for example, every third Maine Coon breed is positive for HCM.

Hypertrophic cardiomyopathy is the most common heart disease in cats, with the risk of sudden death in affected animals due to defects that increase the thickness of the left ventricular muscle. Maine Coon cats have been found to have a mutation in the genes that encode proteins responsible for the contraction of the heart muscle associated with increased risk development of HCMP. A decrease in the amount of a protein called myomesin - one of the proteins required for normal contraction of the heart muscle - has been reported in HCM Maine Coons.

Hypertrophic cardiomyopathy is a disease in which the heart muscle becomes uncharacteristically dense (in the case of dystrophic cardiomyopathy, the muscle becomes thinner), and makes it difficult for the heart to function effectively, which ultimately leads to cardiac arrest and / or embolism (formation of blood clots, blood clots). This mutation can cause the development of the disease and the sudden death of the animal at the age of 4 years or more. young age in individuals who carry two copies of this mutation (homozygotes). Cats with one copy of the mutation in their genome have a longer life expectancy, but they can still develop HCM.

Currently, a test has been developed to determine the presence of this mutation in the cat's genome. The test results should be interpreted as follows:

Symptoms of cardiomyopathy

Shortness of breath - appears mainly after an energetic pastime or a stressful situation, the cat begins to breathe with its mouth open.
High fatigue - the animal is less active than before, plays little, sleeps a lot, external weakness manifests itself.
Cyanosis is a blue discoloration of the skin on the lips and next to the nose, as well as the mucous membrane of the gums and inside the ears.
Pulmonary edema (shortness of breath occurs even at rest)
Enlargement of the heart (by ultrasound).
Accumulation of fluid in the chest cavity.
Thromboembolism - blood clots and blockages blood vessels.

For the combination recent symptoms death usually follows. Some symptoms can only be diagnosed by a veterinarian-cardiologist.

Hidden killer

Although HCM is hereditary, it does not manifest itself when a kitten is born. Instead, this disease develops over time. The development and severity of HCM can be different even in animals that are born in the same litter. These changes are due to the unique characteristics of autosomal dominant inheritance known as "fluctuations" and "incomplete penetrance". Often, fluctuations are manifested due to gender differences.

The mechanism of development of this pathology lies in the fact that as the heart muscle thickens, the volume of the left ventricle decreases, as a consequence of this, the volume of blood pumped through it decreases. Stagnation develops, leading first to an increase in the left atrium, pulmonary veins, and then, at later stages, to the development of pulmonary edema and / or hydrothorax (accumulation free liquid v pleural cavity). Moreover, the insidiousness of this disease lies in the fact that the first symptom may be pulmonary edema and / or death. In some cases, symptoms such as shortness of breath (breathing with an open mouth) and poor exercise tolerance may occur in the early stages.

One of the most frequent complications HCM, sometimes manifesting against the background of the absolute visible well-being of the cat, is thromboembolism. Expansion of the left atrium and blood stasis leads to an increased risk of blood clots, which in turn lead to blockage of vital vessels and sometimes death, especially in the case of late treatment for veterinary care... Most often, blockage occurs at the level of the femoral arteries, in which case the first symptom will be sudden paralysis of the pelvic limbs and severe pain syndrome- the cat screams and does not stand on its hind legs. In such cases, hours, if not minutes, are counted. How faster patient goes to a specialized clinic, the more chances you have to restore blood flow and minimize the risk of complications.

Early diagnosis of cardiomyopathy

Considering all of the above, it is extremely important timely diagnosis... The earlier the doctor starts treatment, the longer the patient can live and the less the risk of developing adverse complications.

The most accurate method for diagnosing HCM is echocardiography - ultrasound procedure heart by a cardiologist. However, in some cases, additional chest x-ray and electrocardiography are also important.

During ultrasound examination the doctor conducts a series of measurements and calculations, while obtaining clear objective data, on the basis of which a conclusion is made whether the patient has a pathology or not, whether there is a risk of its development in the future.

Moreover, given the increased risks, it is especially important for the representatives of the breeds described above to undergo such a survey. Proof of the particular importance of this problem is, for example, the fact that in the countries of Western Europe it is legally prohibited to use in the breeding or sale of cats of risk group breeds that do not pass regular examinations a cardiologist for HCM (HCM-screening tests). Based on the results of such tests (ECHO-KG), the cat is issued a certificate confirming that it has no signs dangerous pathology... The results of such tests are recognized by foreign colleagues. As a rule, such examinations in breeding cats are carried out annually, starting from the second year of life.

In addition, if you own a cat of one of the breeds of the risk group or sometimes notice the symptoms described above in your pet (no matter what breed) and are going to do general anesthesia (for example, about castration or sterilization), it is highly advisable to undergo an examination before anesthesia. cardiologist for the absence of HCM in your pet. Unfortunately, it is not uncommon for serious complications(up to pulmonary edema and death) in the postoperative period (the first 2 weeks after anesthesia) in patients with latent HCM.

Treatment of hypertrophic cardiomyopathy

If the doctor nevertheless detects HCM in a patient, do not despair. There are modern effective schemes treatments for this disease, especially effective in identifying the disease on early stage... The drug of choice for such patients is, first of all, drugs of the beta-blocker group, and, if necessary, drugs are prescribed for the prevention of thromboembolism, diuretics, calcium channel blockers, ACE inhibitors, etc. it is worthwhile to self-medicate and get carried away " folk remedies". Taking medications must be permanent, the patient must be shown for scheduled follow-up examinations and not interrupt the prescribed treatment regimen.

Hypertrophic cardiomyopathy and breeding

It is extremely important to understand that if a cat has HCM, it is necessary to immediately withdraw it from breeding plans and check the entire line in order to avoid further spread of the pathology.

The isolation of HCM from the Maine Coon genetic base is of utmost importance for the subsequent development of the breed.

Cardiomyopathies- a collective concept, which is understood as a whole group of heart diseases, characterized by dystrophic changes in the myocardium (heart muscle).

By the nature of the changes occurring in the heart, several types of cardiomyopathies are distinguished. The main, and, most common, include Hypertrophic cardiomyopathy (HCM) and Dilated cardiomyopathy (DCM).

HCM is characterized by a thickening of the walls (totally or only one area) and a decrease in the cavity of the ventricles of the heart. It is the most common form of cardiomyopathy in cats (about 65% of all CMP in cats).

DCM, on the other hand, is characterized by wall thinning and expansion of the ventricular cavities. It is relatively rare (about 5%).

It is also necessary to say the same about other forms of cardiomyopathy: RCMP (restrictive cardiomyopathy, as well as in HCM, the pathological process captures the left ventricle, but the thickening of the myocardium is less pronounced), ARVD (arrhythmogenic right ventricular dysplasia- changes affect mainly the right ventricle), in some cases, transformations in the heart are difficult to unambiguously interpret, such diseases are referred to the "Unclassified cardiomyopathies" group.

Causes of the disease

Depending on the causes of cardiomyopathy, there are:

Primary or idiopathic. It is believed that this form of the disease is of a genetic nature. At the moment, gene mutations have been identified that lead to HCM in Maine Coon and Ragdoll cats. Several other breeds, including the British Shorthair, American Shorthair, Scottish Fold, Sphynx, Persian, Norwegian Forest, have a familial predisposition to Hypertrophic Cardiomyopathy. In these breeds, inherited forms are also assumed, research in this area is ongoing. It is also believed that cats of the Abyssinian, Thai, Burmese, Siamese breeds are predisposed to DCM. In rare cases, idiopathic cardiomyopathy is also diagnosed in outbred animals.

Fig. 2. Maine Coon cats

Fig. 3 British Shorthair

Fig. 4 Sphinx

Secondary the form of the disease is suspected in cases where there is a disease that caused changes in the myocardium. So, for example, arterial hypertension, hyperthyroidism, inflammatory process in the heart muscle - myocarditis, heart defects (aortic stenosis), and to DCM - a lack of taurine with unbalanced feeding, myocarditis, heart defects.

Fig. 5 Burmese cat

Fig. 6 Abyssinian cat

The mechanism of the disease (pathogenesis)

The pathological process can affect various parts of the myocardium, but greatest value in the manifestation of the disease has a lesion of the left ventricular myocardium. With DCM, this is a decrease in the "pumping" function, the inability of the ventricle to adequately contract and expel blood into big circle blood circulation. And with HCM, on the contrary, this is not the ability of the heart muscle to relax, and, as a result, insufficient blood volume entering the systemic circulation. Whatever the reason for the changes, these changes lead to an increase in pressure in the left atrium, and subsequently, an increase in pressure in the pulmonary veins - the vessels through which blood enters the left atrium. Then the pressure rises to more small vessels and the capillaries of the lungs and as a result, pulmonary edema develops, sometimes hydrothorax. These are the most formidable manifestations of the disease that can lead to the death of an animal.

Involvement of the "right heart" in the process sometimes causes the accumulation of fluid in abdominal cavity(ascites), chest cavity (hydrothorax), pericardium.

In addition to these obvious symptoms, a whole cascade of adaptive reactions follows, which subsequently lead to irreversible changes, both in the heart itself and in other organs. These processes include tachycardia (uncontrolled prolonged increase in heart rate), arterial hypertension (increased blood pressure), vasoconstriction (vasoconstriction), thirst (rarely in cats).

Clinical picture

In the early stages of the disease, and, sometimes, even more pronounced changes in the heart, symptoms may be absent. In some cases, you may notice that the cat has become less mobile, with physical exertion, the respiratory rate increases. This "latent" stage can last long enough, the symptoms begin to increase, as a rule, after some provoking factor: stress, surgery, anesthesia.

The main manifestation of the disease is rapid breathing - shortness of breath. If at the beginning of the disease it can manifest itself imperceptibly, for a short time, mainly after physical exertion, then over time it progresses, manifests itself already at rest. With the development of pulmonary edema, the cat takes a forced position, often breathes with an open mouth, you can see that the tongue and gums acquire a bluish tint. If in this situation you do not show emergency assistance, the animal will die.

Another complication that develops with cardiomyopathies in cats is vascular thromboembolism. A thrombus formed in the dilated chambers of the heart, having torn off, begins to migrate through the blood vessels. Manifestations in thromboembolism depend on in which vessel the thrombus stops and clogs it. The most common localization is femoral arteries... In this case, paresis of the pelvic limbs develops. The cat does not lean on its paws, the pads of the fingers are cold, the pulse on the affected limbs is not palpable. As a rule, severe pain syndrome is present.

In some, very rare cases, sudden death may be the only manifestation of the disease.

How to identify?

The "gold standard" in the diagnosis of cardiomyopathies is the echocardiographic method (ECHO of the heart).

For Maine Coon and Ragdoll cats, there are special genetic tests for the presence of mutations that cause HCM (HCM test). But this test does not exclude Echocardiography, since the presence of this mutation does not mean the presence of the disease itself. The disease may develop later, in different forms and varying degrees of severity. Changes detected by ECHOkg are the basis for starting treatment. Likewise, a "negative" result does not exclude echocardiography. It has been proven that the disease can develop in animals with a "negative" test for HCM, it is assumed that the disease is polygenic in nature (as in humans, more than 400 gene mutations that lead to HCM are known).

Genetic testing of cats is necessary, first of all, for planning breeding work, culling out of breeding individuals that are carriers of mutated genes.

In addition to ECHOkg, during a cardiac examination, electrocardiography (ECG) may be required to detect complications in the form of heart rhythm disturbances. In addition, in some situations, x-rays, ultrasound of the chest cavity, and laboratory studies are used.

How to treat?

Treatment is aimed at eliminating the symptoms of congestive heart failure and preventing pulmonary edema; for this purpose, diuretics are prescribed. In order to understand the severity of congestion, a breath count test is used. This is an easy way to assess the condition of an animal at home, which even the owner can use. To do this, at rest, the respiratory movements are counted (that is, each inhalation-exhalation) per minute. Normally, the respiratory rate does not exceed 27 respiratory movements per minute.

For the treatment of chronic heart failure, drugs from the group of ACE inhibitors are prescribed.

When enlarged heart chambers are identified, thrombus prophylaxis is necessary, for this, as a rule, drugs from the group of antiplatelet agents are prescribed.

Β-blockers are sometimes used to control tachycardia and improve myocardial elasticity (with HCM).

In some situations, drugs are needed to enhance myocardial contractility.

Treatment should be prescribed by a veterinarian cardiologist based on the examination of the cat.

How long will a cat live?

Despite the common principles and stages of the development of the disease, predicting the life expectancy of cats with cardiomyopathy is sufficient complex issue... Even the same forms of cardiomyopathy in different animals are individual in nature, therefore, life expectancy and the severity of the manifestation of the disease can vary significantly. This is because, in addition to the causes of the disease, there are a number of external and internal factors (such as stress, accompanying illnesses and even the character of the cat) that can influence the course of the disease.

What to do? prevention

Prevention consists in early detection diseases and competent breeding work. There are no drugs with proven effectiveness that prevent the development of the disease. Therefore, it is very important to timely identify the disease.

Risk breeds * before surgery under general anesthesia.
Regularly to animals of the breeds of the risk group * once every 1-1.5 years until they reach the age of five.
Older cats over 6 years old before surgery under general anesthesia.
Animals showing rapid breathing with little exercise or at rest, increased fatigue during exercise or when heart murmurs are detected on a therapeutic examination, rhythm disturbances.

Hypertrophic cardiomyopathy is a common form of cardiac pathology, accompanied by thickening, hypertrophic changes in the muscle layer of the organ. The disease is characterized by a deterioration in myocardial nutrition, a decrease in blood volume. The disease can be primary in nature, as well as develop as a result of concomitant ailments.

According to veterinary statistics, hypertrophic cardiomyopathy is diagnosed in 45% furry pets with symptoms of heart failure.

Read in this article

Interesting facts from the medical history

Hypertrophic cardiomyopathy is a relatively new disease in veterinary practice. Intensive research into cardiac pathology was carried out in the early 2000s in the United States. A large population of Maine Coon and Ragdoll cats have been scientifically analyzed to carry a mutation leading to heart disease.

American scientists have concluded that a mutation in the gene responsible for myosin-binding protein is the main reason for the genetic predisposition of Maine Coons and Ragdoll cats to hypertrophic cardiomyopathy.

Based on the studies carried out, genetic test systems were created. However, their widespread use was not justified, since even with the selection of mutation-negative producers in the offspring, there were cases of heart disease.

By 2010, German scientists completed large-scale studies of a large population of Maine Coons and Ragdolls in order to identify carriers of the mutation. It turned out that genetic tests proposed by American scientists and widely used around the world are reliable only for cat populations in the United States.

Reasons for the development of hypertrophic cardiomyopathy

Studying the causes leading to the development of heart ailments in furry pets,
allowed to make an unambiguous conclusion about the genetic predisposition of certain breeds to hypertrophic cardiomyopathy. It is reliably known that more than 10 genes are involved in the development of the disease.

Most veterinary specialists are inclined to believe that gene mutations are the main cause of the development of the disease in domestic cats. Defects in the transmission of genetic information, leading to hypertrophic cardiomyopathy, are most often manifested in such breeds as Maine Coon, Ragdoll, Persian, Sphynx, Abyssinian cats.

Scientific studies show that if a defective gene is found on each pair of chromosomes (homozygous animal), the risk of heart disease increases significantly compared to a heterozygous cat (if one is normal in a pair of chromosomes and the other is defective).

Among such popular breeds, like the British shorthair, Siamese, Russian blue, Siberian, there is no direct genetic relationship between mutational changes and the development of cardiac pathology. However, these breeds are often prone to secondary forms of the disease.

In addition to the genetic cause that affects the development of cardiomyopathy, veterinarians identify the following factors contributing to the disease:

Congenital myocardial pathology in the form of thickening of the walls of the organ and its increase in size - "bull" heart.
Endocrine diseases: overactive thyroid gland, acromegaly. Increased hormone production thyroid gland leads to tachycardia, worsens trophism of the heart muscle. The increased production of growth hormone (acromegaly) leads to a thickening of the walls of the heart.
Unbalanced taurine diet. The amino acid reduces the load on the heart, has an anti-ischemic effect, regulates contraction muscle fibers myocardium and protects cell membranes from damage. Taurine deficiency leads to impaired functional state heart muscle.
Constant increased blood pressure in a pet, it leads to wear and tear of the heart muscle.

Malignant neoplasms, in particular, lymphoma, contribute to changes in the structure of the myocardium.
Chronic intoxication different etiology... Poisoning with household pesticides, overdose of drugs, waste products of helminths have an adverse effect on the muscle fibers of the heart muscle, leading to ventricular hypertrophy.
Pulmonary diseases such as pulmonary edema.

What happens to the heart in a cat with pathology

Disturbances in the functioning of the heart muscle begin after certain morphological changes occur in the organ. With the development of hypertrophic cardiomyopathy, pathological destruction is primarily the left ventricle and the interventricular septum.

A defective gene leads to the fact that the body is not able to produce a sufficient amount of a specific protein - myosin, which is the basis of the myocardium. The body begins to compensate for the lack of muscle fibers with connective tissue. The myocardial wall thickens. The organ seems to be scarring.

Thickening of the myocardial wall leads to a decrease in the volume of the left ventricle, and often the left atrium. Besides, connective tissue reduces the elasticity and distension of the heart. There is a weakening of the pumping function of the organ.

Thickening of the myocardium leads to the fact that blood stagnates in the atria and the functioning of the atrioventricular valve is disrupted. Obstruction of the aorta occurs, circulatory deficiency occurs.

The development of hypertrophic cardiomyopathy affects all parts of the heart and affects the blood circulation of the body as a whole. This is due to the fact that there is a spasm of the peripheral bloodstream, overflow of the pulmonary vessels with blood. In a sick animal, blood clots form due to a slow blood flow in the stretched chambers of the heart.

Types of hypertrophic cardiomyopathy

In veterinary practice, it is customary to distinguish between primary and secondary cardiomyopathy. Primary, having genetic predisposition, the form of the disease manifests itself, as a rule, up to 5 years of age of the animal. Secondary form most common in older animals and is more common in cats over 7 years of age. This type of pathology develops due to diabetes mellitus, kidney disease, endocrine system.

By the nature of the course, primary cardiomyopathy can be obstructive and non-obstructive. In the first case, the mitral valve is involved in the pathological process. In the case of a non-obstructive form, changes on the part of the bicuspid valve do not occur.

Symptoms of Feline Cardiomyopathy

Heart disease occurs most commonly in males. Cats are less prone to myocardial disease. As for age, pathology can affect both a young animal and an elderly animal. There is no clear connection between the disease and the age of the pet.

The disease can take place in an explicit and latent form in terms of manifestation clinical signs. With an obvious pathology in an animal, the owner may observe the following symptoms:

Lethargy, apathetic state of the pet. The cat stops actively participating in games, tries not to make unnecessary movements, lies and sleeps a lot. The animal may have a low temperature - hypothermia.
Heavy breathing, shortness of breath. With active physical activity, the animal, due to the slowing down of blood flow in the pulmonary veins, has difficulty breathing. The owner can watch the cat begin to breathe quickly by sticking out its tongue. Respiratory movements are committed in this case not by the chest, but by the abdomen.
Asthma attacks, loss of consciousness, fainting. Severe shortness of breath often ends with these symptoms due to oxygen starvation brain. In this case, the pulse is threadlike.
Due to lack of oxygen, the mucous membranes become bluish (cyanosis).
A reflex cough is due to the pressure of the enlarged heart on the trachea. The animal assumes a characteristic posture: leaning on all limbs, it stretches its neck and head forward. The front legs are wide apart for better ventilation.

and ascites. As a result of the effusion of exudate, edema is formed in the chest and abdominal cavity.
Paralysis hind legs the cat develops in advanced cases of the disease, when blood clots close the lumen of large blood vessels in the pelvic region.
Young animals recruit poorly muscle mass, lag behind in development from breed standards and their peers.

In many cases, hypertrophic cardiomyopathy occurs secretly, without obvious clinical signs and ends in death. Sudden death is often the only symptom that the animal was experiencing heart problems.

Diagnosis of hypertrophic cardiomyopathy

The difficulty of detecting cardiac pathology in a pet is due to the latent nature of the course of the disease and a long absence clinical picture... Your veterinarian may suspect myocardial problems during a clinical examination and listening to heart murmurs. Auscultation of the chest helps to identify systolic murmurs, cardiac arrhythmias, the so-called gallop rhythm.

Having detected heart murmurs and rhythm disturbances, the veterinarian, as a rule, prescribes X-ray examination chest, electrocardiography and echocardiography of the heart.

X-ray examination can detect not only an increase in the left ventricle and atrium, but also reveal pleural effusion. ECG of the heart reveals abnormalities in its work in 70% of patients with hypertrophic cardiomyopathy of cats.

X-ray (lateral and frontal projection) of a cat with HCM

Most informative method diagnosis and differentiation from other diseases in cardiomyopathy is an ultrasound examination of the organ. The method allows you to estimate the thickness of the heart wall, the diameter of the aortic opening. With the help of an ultrasound of the heart, a veterinarian can assess the size and shape of the atria, blood flow in the chambers of the heart, and detect blood clots.

For what echocardiography shows in cats with HCM, see this video:

Treatment of hypertrophic cardiomyopathy in cats

Therapy for this pathology is aimed primarily at reducing congestion, regulating heart rate, prevention of pulmonary edema and prevention of blood clots. If hydrothorax is detected in a sick cat in a specialized clinic, a puncture of the chest is performed in order to pump out the pleural effusion.

To reduce congestion and eliminate edema, Furosemide is used parenterally. The dosage and frequency of application is determined by the veterinarian based on the picture of the echocardiographic examination of the diseased organ.

Beta-blockers have been shown to be effective in treating hypertrophic cardiomyopathy in cats. The drugs reduce the heart rate, suppress tachyarrhythmias. Beta-blockers reduce myocardial oxygen demand and the phenomenon of fibrosis in the organ.

In the treatment of the disease, calcium channel blockers are used, for example, Diltiazem, Delacor, Cardizem. The drugs reduce the heart rate, have a positive effect on the relaxation of the heart muscle.

In addition to complex therapy, maintenance and nutrition play an important role in the treatment of sick animals. A sick cat should be protected from stressful situations, provide peace. The diet should be balanced primarily in terms of taurine content. On the recommendation of a veterinarian, the animal may be given the amino acid orally.

The forecast depends on the following factors:

timeliness of pathology detection;
manifestation of clinical signs;
severity of symptoms;
the likelihood of pulmonary edema;
the presence of thromboembolism.

Veterinary practice shows that cats with moderately pronounced enlargement of the left ventricle and atrium often live to old age. In the presence of severe heart failure, congestion, the prognosis is cautious. Cats with significant cardiac muscle hypertrophy live 1 to 3 years. An even more cautious prognosis, up to unfavorable, with the development of thromboembolism.

The actions of the owner in relation to the animal when confirming the diagnosis

Experienced breeders and veterinarians give the owner of a sick cat the following guidelines:

Hypertrophic cardiomyopathy is a common heart disease in cats. The most common is the congenital form of the disease. Maine Coons and Ragdolls are susceptible to the disease much more often than representatives of other feline breeds. Typical clinical signs indicate serious violations in the myocardium.

The prognosis for a sick cat is generally cautious. If hypertrophic cardiomyopathy is detected, experts recommend not letting the animal go into breeding.

Feline hypertrophic cardiomyopathy (HCM or HCM) is a very insidious and common feline disease characterized by thickening of the predominantly left ventricular wall and interventricular septum. In this case, there is a significant decrease in the volume of the left ventricular cavity, which can provoke an increase in the left atrium. The process involves the myocardium, which leads to a violation normal functioning heart muscle. According to statistics, most often this problem occurs in males.

Etiology of hypertrophic cardiomyopathy in cats

Feline hypertrophic cardiomyopathy is divided into two types: primary (the origin is not fully understood) and secondary (as a consequence of any disease). Primary, in turn, is obstructive and non-obstructive.

Obstructive - high pressure is created in the cavity of the left ventricle due to an increase in the myocardium, blood flows into the aorta at a greater speed, this process resembles a whirlpool. Due to this vortex blood circulation, the leaf of the mitral (bicuspid) valve spontaneously opens and closes.
Non-obstructive - everything is the same, only a high blood velocity does not affect the function of the bicuspid valve.
Acquired (secondary) - is directly related to age-related changes and concomitant diseases, which are characterized by changes in the myocardium. The reasons may be disruption of the endocrine system, infectious diseases, toxic substances, trauma. Such diseases rarely lead to severe manifestations of heart failure.

A genetic predisposition can also be attributed to primary cardiomyopathy - the development of heart failure is hereditary. This disease is transmitted from generation to generation to certain breeds of cats. Special attention should be given to such breeds as British, Scottish, Persian, Maine Coon, Sphynx and their mestizo. Occasionally, this disease manifests itself in outbred animals, here we mean genetic inheritance.

In the vast majority of cases, hypertrophic cardiomyopathy manifests itself at the very beginning of an animal's life, starting from six months.

Cats diagnosed with cardiomyopathy are not allowed to further breed for offspring. This is the only prevention of reducing the risks of developing myocardial pathology, which may be in future generations.

Symptoms of hypertrophic cardiomyopathy

The main symptoms of feline hypertrophic cardiomyopathy are:

The depressed state of the animal;
Heavy breathing with wheezing or even “gurgling”;
Dyspnea;
Tachycardia;
The mucous membranes become bluish;
Thromboembolism (in most cases, one pelvic limb fails, occasionally both);
Heart murmurs;
Pulmonary edema;
Accumulation of fluid in the chest cavity (hydrothorax);
High blood pressure;
Fainting.

Cats with heart pathologies have no cough !!!

Death can come suddenly !!! Therefore, if at least one of the symptoms appears, you should contact the nearest veterinary clinic to diagnose the disease and provide the necessary veterinary care.

It is not excluded that the disease can proceed latently, that is, hidden. The animal is not worried about anything and it does not in any way manifest the fact that changes are already taking place in its body. But any impact from the external environment can provoke the rapid development of this pathology. It's mostly stress. It can also serve as a catalyst infusion therapy(intravenous drip of drugs) in the event that the volumes and rate of the infused fluid do not correspond to the parameters of the animal.

At the expense of high blood pressure congestion occurs in the vessels, against the background of which pulmonary edema develops. Swelling can lead to fluid buildup in the pleural space. It becomes difficult for the animal to breathe. Breathing becomes heavy, an insufficient amount of oxygen enters the body, which can lead to hypoxia.

It is possible to suspect that the cat has developing disease hearts after physical exertion, severe stress... The animal lies on its stomach and spreads its paws wide, breathes with open mouth like a dog. After the animal has rested, its condition may return to normal.

Often occurs after a few days or immediately after using general anesthesia. If it manifests itself immediately, then in a severe form.

Diagnosis of hypertrophic cardiomyopathy

The most an important milestone in the diagnosis of cardiomyopathy is the collection of anamnesis. A cat owner knows their pet's habits better than anyone. Therefore, it is important not to miss any, even the slightest change in the behavior of the animal.

Echocardiography- this method is the most informative in making a diagnosis, since it is possible to obtain the necessary, more detailed data on the structure and functionality of the heart. All young cats that are at risk for breed should be mandatory echocardiography (ultrasound examination of the heart) to exclude or, conversely, confirm the presence of cardiac pathology. And also without fail before any operation, which includes general anesthesia, in order to eliminate the risks of anesthesia, which sharply increase when the presence of progressive hypertrophic cardiomyopathy is detected. We visually assess the work of the heart, measure the wall of the left ventricle, the interventricular septum. Normally 5 millimeters. 6 millimeters are suspicious animals. From 6 millimeters and above - sick.

An enlarged left atrium in a cat.

Hydrothorax in a cat.

Electrocardiography- is not always a case study. The ECG can be judged on the expansion of the QRS interval, ventricular and supraventricular arrhythmias, sinus tachycardia.

X-ray diagnostics - X-rays are made in two projections on the side and on the back. This allows you to visually assess the size and shape of the heart, the presence of pulmonary edema, the presence of fluid in the pleural cavity.

Auscultation- using a phonendoscope, it is possible to diagnose the presence of extraneous murmurs in the heart and lungs, heart rhythm (with hypertrophic cardiomyopathy, gallop rhythm), the presence of tachycardia.

Measurement of pressure using a veterinary tonometer. Usually the pressure is high. The procedure itself is painless and does not take more than two minutes.

Visual assessment the condition of the animal is very important. When examining the animal, we pay attention to the visible mucous membranes, which are often cyanotic (cyanotic).

In severe hypertrophic cardiomyopathy, every minute counts. An examination of the animal is not carried out until its condition is stabilized, otherwise the process of the development of the disease against the background of the stress of the animal can be aggravated, which can lead to death.

Animals with diseases leading to impaired heart function, secondary hypertrophic cardiomyopathy, as prescribed by the treating person veterinarian undergo a cardiological examination.

Treatment of hypertrophic cardiomyopathy

Special equipment is required to treat such a serious illness, so home treatment is not possible if the animal is in serious condition.

First of all, they stabilize the condition of the animal. The cat is placed in a special chamber with a constant supply of oxygen, the so-called oxygen box.

After the animal's condition has more or less returned to normal, it is necessary to conduct research. And also to divert fluid that could accumulate in the pleural cavity by puncturing the chest wall - thoracocentesis. After such a procedure, it becomes noticeably easier for the animal to breathe.

The appointment of treatment is carried out strictly by a veterinary specialist, drugs and dosage are strictly individual. The treatment regimen is drawn up depending on the severity pathological process and the state of the animal and the characteristics of its body. The treatment of the animal takes place in a veterinary clinic under the supervision of highly qualified specialists. On average, this treatment lasts about three days. After this time interval has passed, we can already talk about the forecast.

All manipulations with the animal are carried out in such a way that the animal feels as comfortable as possible and does not experience unnecessary stress. Therefore, in inpatient treatment, a minimum of manipulations for the animal should be carried out, only if necessary, and the provision of complete rest to it. Owners are also encouraged to visit their pets. And also, in order to create maximum comfort for the animal, all research is best done in the presence of the owner. The unusual environment of the clinic is stressful for the cat, but when the animal realizes that its owner is nearby, sees familiar faces, it gives the animal more confidence and experiences less stress and fear.

Cats that show positive dynamics in inpatient treatment have every chance that their further treatment will take place at home, in a familiar environment. The owner of such an animal should regularly report the condition of his pet to the veterinary clinic, where they are registered.

The same is made for the animal special diet, restrictions on physical activity are introduced. In no case should you overfeed the animal, as obesity leads to an additional burden on the heart.

Age animals with a secondary type of hypertrophic cardiomyopathy need to stop the root cause that caused the development of myocardial pathology.

However, this is so individual, there are different situations, various diseases or even a whole complex of diseases. And it does not always happen that after eliminating the root cause, heart problems resolve on their own. In such cases, it is often prescribed additional treatment drugs aimed at maintaining the functions of the heart muscle and constant monitoring of the condition.

Such animals should be registered with a veterinarian cardiologist, regularly conduct research on the state of the heart muscle.

Fully recovered animals are also recommended to be examined by a cardiologist at least once a year, however, like all other animals, regular preventive examinations are recommended. More precise recommendations, in each individual case, the attending physician gives himself the next time you need to visit the veterinarian to monitor the condition.

An important condition in the treatment is compliance with the recommendations for feeding, care and maintenance of the animal.

Summing up, we can say that the treatment is aimed at eliminating congestion and other symptoms of cardiomyopathy, improving the work of the heart muscle, preventing the development of thromboembolism, and improving the quality of life of the animal.

Prognosis for hypertrophic cardiomyopathy

In primary hypertrophic cardiomyopathy, the prognosis is very ambiguous. It all depends on the form, course and response to treatment.

If during the first days inpatient treatment there are visible improvements, then the prognosis is inclined towards a favorable outcome of the disease, taking into account the fact that the animal should be provided with complete rest. Any stress can aggravate the course of the disease.

In the case of a severe form of HCM, if during the first 1-2 days there is no improvement, and the condition only worsens, unfortunately, the prognosis is poor.

Hypertrophic cardiomyopathy caused by any disease has a positive trend in most cases, eliminating the cause of myocardial hypertrophy and maintaining the functionality and condition of the heart muscle with drugs.

Owners of cats and cats who have not performed echocardiography on their animals before general anesthesia for some reason, a few days after the surgery, you should be as focused on your pet as possible, monitor its condition and behavior. In case of any, even the slightest hint of heart problems, immediately seek veterinary help.

Therefore, if you are the owner of a cat or kitten and your animal is predisposed to heart disease by breed, be sure to perform an ultrasound examination of the heart before any surgical intervention, be it sterilization or castration, in order to avoid an unpleasant "surprise" in the future!

Feline cardiomyopathy Comparison of feline cardiomyopathy

Myocardial disease is the most common form of heart disease in cats. All myocardial diseases can lead to the development of congestive heart failure.

Three types of cardiomyopathy

1. Dilated cardiomyopathy (DCM): Feline dilated cardiomyopathy is caused by a lack of taurine (although some cases may be idiopathic). With DCM, eccentric hypertrophy develops in the muscle wall of the heart and contractility decreases, which leads to a decrease in cardiac output. DKM is rare today, as taurine is added to commercial cat food.

2. Hypertrophic cardiomyopathy is common in cats. With hypertrophic cardiomyopathy, concentric hypertrophy develops in the ventricular wall, which is characterized by a thickening of the ventricular wall. The pumping function of the heart is good, but it cannot relax normally during diastole. In addition, the thickening of the ventricular wall leads to a violation of the location of the AV valves, therefore, the animal may develop insufficiency mitral valve... Dynamic obstruction of the aortic outflow tract may occur with systolic forward movement of the mitral valve. Stenosis can occur in the middle / end of systole, so it usually doesn't cause problems.

3. Restrictive cardiomyopathy occurs when too much fibrous tissue forms in the endocardium, myocardium, or subendocardial tissue. Endocardial fibrosis is the most common cause. Fibrosis usually leads to diastolic dysfunction. The elasticity of the heart decreases, it cannot adequately fill and perform a pumping function. The heart must be filled with more high pressure than normal, resulting in higher diastolic blood pressure. This leads to increased capillary pressure and pulmonary edema or pleural effusion.

Clinical signs: most cats present with acute heart failure, even though they have had heart damage over the years. Heart disease develops slowly, and the activity of cats gradually decreases. Most owners do not notice this exercise intolerance. When the swelling or effusion becomes severe, cats have sharp deterioration states.

1. Dyspnea is caused by pulmonary edema or pleural effusion.

2. During auscultation, murmurs are often heard from the left or from right side chest. Often cats have a gallop rhythm, but the heart rate can rise to such an extent that the gallop rhythm is difficult to hear.

3. When X-ray examination you can see an increase in the atria (an increase in the left or both atria). In the case of DCM, the ventricles also enlarge. In hypertrophic cardiomyopathy and sometimes in restrictive cardiomyopathy, the dorsoventral heart may be in the shape of a valentine heart.

Forecast: in cats, cardiomyopathy is difficult to define. These cats may respond poorly to drug therapy and live for only a few days, or may respond well to drug therapy and live for many years. The prognosis depends on the response to therapy and the owner's ability to treat the cat.

Treatment

The immediate goal is to stabilize and support the animal with heart failure. After the animal is stabilized, further diagnostics are carried out and you can switch to supporting drugs. Try to stabilize the animal without causing too much dehydration and hypotension (minor permissible), as both can lead to renal failure... It is better to dehydrate and then rehydrate than to let the animal die from chronic heart failure. A. Oxygen administration. If the animal is unstable due to dyspnea, oxygen is administered to it by insufflation or by placing it in an oxygen chamber. If the animal lacks oxygen, then first provide it with oxygen, and then diagnose.

Principles drug therapy

1. Before the introduction of any drug, first determine:

a. The purpose of the treatment? It is necessary to control arrhythmias, increase myocardial contractility, reduce systemic resistance against which the heart ejects blood (afterload), and reduce hydrostatic capillary pressure.

b. How to evaluate the effectiveness of drug therapy? For example, if attempts are made to reduce pulmonary congestion, respiratory rate should be monitored and repeated x-rays should be performed.

c. Signs that will indicate that it is necessary to cancel the drug? It may be necessary to make a decision to discontinue the administration of the drug if no result was obtained within the first 24 hours, depending on the severity and immediate danger.

The drug is discontinued if it lowers the heart rate or myocardial contractility too much, or if vomiting or anorexia occurs during its use.

2. Whenever possible, start with monotherapy. Some time after the start of drug administration, its effectiveness is assessed. If the goal is not achieved, its administration is stopped, the dose is changed, or another drug is additionally prescribed. Make only one change at a time and allow enough time for the changes to take effect. Evaluate before and after each change.

3. Multiple drugs should be avoided whenever possible, as this often leads to anorexia, especially in cats.

4. In severe heart failure, it may be necessary to administer several drugs.

SPECIAL PREPARATIONS

A. Diuretic drugs of first choice:

1. Usually the first choice is furosemide (2-8 mg / kg). Its dose depends on the condition of the animal. Furosemide - relatively safe drug... Unfortunately, with heart failure, the forward movement of blood is reduced, therefore, the blood supply to the kidneys is impaired. As a result, furosemide may not be as effective as in animals with normal renal perfusion. The effectiveness of lasix is assessed by monitoring the frequency of respiration and its nature, urinary excretion and using radiography.

a. V severe cases therapy should be aggressive. Initially, furosemide is prescribed at a dose of 8 mg / kg IV every hour until the respiratory rate drops to 50-60 per minute. Then, 5 mg / kg is administered every 2-4 hours until the respiratory rate drops below 50. Then they switch to a maintenance dose. In cats, start at 4 mg / kg. It is very important to first administer the drug intravenously, since after intravenous administration the effect occurs in 5 minutes, while with intramuscular administration it appears after 30 minutes, and when administered orally - after an hour. These animals are likely to develop dehydration. Dogs will have an appetite and recover. water balance immediately after reducing the preload. Cats may need to be rehydrated first before they can eat and drink on their own. The prognosis is poor if the animal is already experiencing dehydration and heart failure.

b. After establishing the primary control dose of furosemide, it is gradually reduced to the lowest possible maintenance dose. It may be necessary to additionally prescribe another drug, such as enalapril.

2. Inhibitors of the angiotensin converting enzyme (ACE inhibitors - captopril, enalapril, lisonopril) act by inhibiting the RAAS. Their overall effect- reduced water retention and vasodilation. Therefore, their mechanism of action is associated with a decrease in preload as well as afterload. Other ACE inhibitors include benazepril and lisonopril.

a. ACE inhibitors are not prescribed for animals with kidney disease. If there is a suspicion that the animal may develop renal dysfunction, a biochemical blood test is performed before the drug is administered, and then five days after the start of the drug administration. In most animals, renal dysfunction develops within 4-5 days after the start of the administration of ACE inhibitors.

B. Venodilators increase venous capacity, thus reducing preload.

Nitroglycerin ointment can be applied to skin covering in the area of auricles or gums. The dose is 0.6 cm per 7 kg every 4-6 hours. The drug should be applied with gloves and in no case given to the owner at home!

C. Positive inotropic drugs increase myocardial contractility and are very effective in myocardial insufficiency (determined by measuring the shortening fraction). Often, when the volume is overloaded, the shortening fraction does not decrease (normally, the shortening fraction in dogs is 34-40%).

1. Digoxin is a weak inotropic drug. It is better to prescribe it for arrhythmias.

2. Dopamine (5-10 μg / kg / min) and dobutamine (2-10 μg / kg / min) are good positive inotropic drugs, but have only a moderate effect on the heart in myocardial insufficiency. These catecholamines are better than epinephrine and isoproterenol in treating heart failure because both drugs increase heart rate.

At high doses, dopamine and dobutamine can also increase heart rate. Dopamine is much cheaper than dobutamine (dobutamine lowers pulmonary venous pressure). All catecholamines have a short half-life and must be given by infusion at a constant rate.

D. Arterial dilators are used to reduce afterload. May cause hypotension. Use only nitroprusside and hydralazine if direct measurement is available blood pressure... Drugs that dilate arterial vessels should not be used with pressure overload (for example, with subaortic stenosis).

1. Nitroprusside has a strong hypotensive effect. This drug requires an artery catheterization to continuously monitor the blood pressure. Just a few drops of the drug can cause significant changes in blood pressure.

2. When hydralazine is administered orally, the effect of the drug develops only after 30 minutes. Hydralazine also induces hypotension.

3. Inhibitors of angiotensin converting enzyme (ACE inhibitors), for example, enalapril (0.5 mg / kg 2 times a day) or captopril (3 times a day), are used to a greater extent because of the diuretic effect; also have a weak dilating effect on the arteries.

4. Amlodipine (a calcium channel blocker like diltiazem and nifedipine) causes dilatation of arterial vessels.

E. Antiarrhythmic drugs digoxin, propranolol, and lidocaine.

Animals should be fed a diet that is limited in salt. Treats should also contain a minimum amount of salt.

Exercise in animals with cardiomyopathy: exercise stress provokes the appearance of clinical signs, but does not contribute to the progression of clinical signs. You can advise the owner not to restrict the cat's movements, since the animal will do this on its own.

Yin S. Complete reference small animal veterinary medicine