Hypertrophic cardiomyopathy in cats: signs and symptoms. Cardiomyopathy in cats

A cat's heart is like a pump that pumps blood. Blood from the right side of the heart, through the circulatory system, enters the pulmonary artery to the lungs, where it is saturated with oxygen and returns to the left side, from where it enters the rest of the body through the aorta.

Left and Right side The heart consists of two upper chambers - the atria, and a lower chamber - the ventricle, which serves as the main pump that pumps blood.

The structure of a cat's heart.

Stops blood from coming back into the right upper chamber during contraction, tricuspid valve. Performs the same function, only on the left side mitral valve. The papillary muscles found in the ventricles are attached to the valves by fibers that prevent the valves from being pushed into the atria when contraction occurs.

Hypertrophic cardiomyopathy in a cat

The essence of the pathology of hypertrophic cardiomyopathy is the abnormal compaction of the muscular wall of the left ventricle - hypertrophy.

Scheme of hypertrophic cardiomyopathy in a cat.

The disease can develop as primary and how secondary disease . Primary reasons Genetic pathological changes may occur, which implies inheritance. A secondary factor may be chronic arterial hypertension, which is usually present due to .

Clinical signs and symptoms

Difficulty breathing in a cat is one of the symptoms of the disease.

The presence of symptoms depends on the intensity of the disease.

The larger the damage, the more pronounced the symptoms.

The main features are difficulty breathing of an animal , shortness of breath often develops into severe attacks.

The previously active pet becomes too slow , cautious, moves slowly.

Sleeps more or simply remains motionless, being in one position for a long time.

Reluctant to make contact with the owner or other animals, more often just ignores .

Further, if the disease progresses, fainting states , from which the cat finds it difficult to get out.

Happen epileptic seizures .

IN advanced stage fluid accumulates in the chest and abdominal cavity , is coming.

The presence of pathology makes it possible to form blood clots, which develops into an arterial embolism.

Diagnostics

Diagnosis is made through comprehensive studies.

Diagnosis of the disease requires complex studies.

An anamnesis is collected, which includes information about diseases suffered by the pet, observations of the owner on the manifestations characteristic symptoms, the animal’s diet, regime, vaccinations. Next, electrocardiography, radiography, echocardiography are performed, and biomarkers are used.

Treatment

Unfortunately, the pathology cannot be completely cured.

It is impossible to completely cure hypertrophic cardiomyopathy in cats.

Therapy used for the disease is aimed primarily at maintaining the general condition of the animal. Therapeutic effect are directed to eliminate the main pathological changes:

elimination of diastolic dysfunction;

control of dynamic obstruction of the left ventricular outflow tract;

elimination of ischemia;

heart rate stabilization;

restoration of basic neurohumoral functions;

elimination of hypercoagulation.

At home

Helping a cat at home is not practical.

If the pet is in serious condition, at first it is kept in an oxygen box. After relief occurs, measures are taken to remove fluid from the pleural cavity to ensure air access and the animal can breathe normally.

At in serious condition an oxygen mask is used.

Medication assistance

Medical assistance consists of in the use of inhibitors : enapril, ramipril, imidapril. Calcium channel blockers in the form of diltiazem. Selective blocker - atenolol. Diuretics – furosemide, spironolactone. Antiplatelet agent – clopidogrel.

Ramipril tablets are prescribed to cats to treat the disease.

Video about hypertrophic cardiomyopathy in cats

A distinctive feature of cats is their unprecedented vitality, and due to this feature, in some ancient religions animals were assigned magical abilities, and it was also believed that the mysterious furry beauties were associated with the other world.

But there are diseases that can turn the cat’s notorious “nine lives” into one, and even then not a very long one. One such disease is cardiomyopathy in cats.

This is a disease characterized by pathological changes in the ventricles of the heart and interventricular septa. The disease belongs to the category of dangerous ailments that can significantly shorten the life of an animal. According to statistics, similar problems more common in males than females

Types of disease

The definition of "cardiomyopathy" includes four categories of diseases affecting the heart muscle of an animal.

Cardiomyopathy is a pathology affecting a cat's heart.

The main types of ailments include:

Hypertrophic cardiomyopathy (HCM). This form of the disease is considered the most common and occurs against the background of thickening of the walls of the heart and an increase in the size of this organ. The result of such pathological processes is a reduction in the volume of blood passing through the arteries, deterioration of nutrition and poor oxygen supply to the heart.
Dilated cardiomyopathy (DCM), when the volume of the heart increases, but the thickness of the muscle tissue does not change. As a result, the muscles become thinner and lose the ability to contract normally, which leads to the development oxygen starvation throughout the body.
Restrictive cardiomyopathy (RCM), which is characterized by fibrosis of the heart muscles. With the development of this form of the disease, the organ acquires rigidity and loses elasticity, as a result of which the animal’s body ceases to receive oxygen and nutrients in the body. required quantities. With such disorders, animals rarely survive beyond the age of two.
Intermediate cardiomyopathy (ICM). There is no description of this type of disease in specialized reference books, since similar diagnosis placed when an animal simultaneously exhibits symptoms of several types of cardiomyopathies.

Heart disease has a significant impact on the well-being, behavior and life expectancy of cats. For this reason, it is important to recognize the disease in a timely manner and take the necessary measures; inaction can lead to rapid death pet.

Causes of cardiomyopathy

What are the reasons for the development of hypertrophic cardiomyopathy in, or manifestations of other types of this disease?

The factor that provokes the development of the disease includes heredity.

The following provoking factors are distinguished:

heredity;
congenital heart pathologies;
the presence of neoplasms and lymphomas;
respiratory diseases ();
infections and viruses ();
arterial hypertension;
violation of metabolic processes;
increased activity of the thyroid gland;
Excessive production of growth hormones.

Also at risk for heart problems are animals that are obese and sedentary lifestyle life.

Symptoms and clinical picture of the disease

The danger of cardiomyopathy is that the animal can for a long time look completely healthy and show no signs of illness. In such cases, only an experienced veterinarian can determine that a cat has heart problems when examining the pet.

Symptoms indicating the presence of a disease of this kind are:

Decrease or increase in heart rate. Each organism has its own norm for the number of heart beats within 1 minute. If the indicator changes up or down, this is a sign of a malfunction of the organ.
Heart murmurs. This symptom can be detected by careful listening chest using a phonendoscope, and it indicates changes in the functioning of the organ.
Heart rhythm disturbance. Certain failures are typical for various diseases this organ, including cardiomyopathy.
The appearance of the “third tone”. When a cat's heart is healthy and functioning normally, muscle contractions are heard in two tones. If there are problems with the heart valve, another one is added to them.

As mentioned above, there are situations when such a violation does not affect the animal’s behavior in any way. But If the cat has become inactive and apathetic, you should immediately contact a veterinarian. It is possible that a specialist will detect signs of heart disease.

If your cat suddenly begins to move less and appears apathetic, she should be seen by a doctor.

Diagnosis of cardiomyopathy

If there is a suspicion of cardiomyopathy, the following diagnostic measures are carried out:

Visual inspection of the animal. With heart problems, the mucous membranes often acquire a bluish tint.
Blood test, general and biochemical, to assess the condition of the animal and confirm or exclude the presence of infection in the body.
X-ray of the heart. When carrying out this study, you can see that the organ is enlarged in size, and if the process has affected the lungs, then their swelling is detected using x-rays.
Echocardiography. Similar diagnostic measure allows you to assess the condition of the heart ventricles and interventricular septa.
ECG. Since cardiomyopathy is characterized by changes in heart function and arrhythmia, this study will help identify such pathologies.

After conducting the necessary research and making a diagnosis, a specialist will prescribe treatment.

Treatment of the disease and medications used

For cardiomyopathy it is carried out drug treatment. The goal of therapy is to normalize cardiac output, reduce risk, and reduce congestion. In addition, it is necessary to prevent the formation of blood clots and monitor heart function.

For cardiomyopathy, the veterinarian prescribes the drug Diltiazem.

In order to cope with the problem and improve general state animal, the following drugs are used:

Calcium channel blockers (Cardizem and Diltiazem). These medications help normalize the heartbeat and improve the condition of the heart muscles.
Beta blockers (Atenolol). The action of these drugs is aimed at normalizing heart rhythms; they are used in cases where pronounced signs of tachycardia and muscle fibrosis are detected.
Decongestant medications (Furosemide). To prevent pulmonary edema and congestion, cats must be given diuretics.
ACE inhibitors (Benazepril and Enalapril). The action of these medications is aimed at reducing pathological manifestations in the ventricles of the heart and interventricular septa.

Since the use of diuretics can lead to dehydration, the animal needs additional infusions of a 5% glucose solution at the rate of 15 ml per 1 kg of weight. In addition, it will be necessary to reduce stressful situations for the animal, since they can provoke sudden stop heart and carry out regular checkups with a veterinarian.

Diet for cats with heart disease

To increase the effectiveness of the treatment, it is necessary to feed the cat in accordance with a special diet.

The principle of proper nutrition is to exclude animals from the diet table salt. As you know, this supplement retains fluid in the body, which can lead to the development of edema, which is extremely undesirable for heart disease.

In addition, it is important that the following substances are present in sufficient quantities in the cat’s diet:

polyunsaturated fatty acids;
l-carnitine;
taurine

To compensate for the lack of these elements, it is necessary to purchase special nutritional supplements for cats. Today, many manufacturers produce vitamins for animals suffering from cardiovascular pathologies, and choosing the appropriate complex is not difficult.

Prognosis for cardiomyopathy

When detecting signs of cardiomyopathy in a pet, pet owners often ask the question: how long do cats with a similar pathology live?

The prognosis for feline cardiomyopathy is ambiguous.

With such diseases, the prognosis is very ambiguous and it all depends on individual characteristics the animal’s body, as well as the nature of the disorder.

As a rule, what the outcome of the disease will be is noticeable already in the first days after the start of treatment. If after 2-3 days there are visible improvements in the animal’s condition, one can hope for a favorable outcome of the disease. However, this is only possible if all the recommendations of the attending physician are followed and the animal is provided with rest.

In situations where, despite the therapy, the animal’s health does not improve, and deterioration is also noticeable, a quick death is quite likely.

With heart problems, some animals live calmly to a ripe old age, but there are cases when, despite the efforts of the owners and the efforts of doctors, the animal dies at the age of 1 to 2 years.

Preventing heart disease in cats

Heart disease in animals can be prevented if preventive measures are followed.

The range of events includes:

and taking vitamins;
carrying out the necessary vaccination;
regular checkups with a veterinarian;
mandatory ultrasonography hearts in cats over 6 months of age;
timely and competent treatment emerging diseases.

In addition, it is important to purchase animals from trusted breeders with a good reputation. IN otherwise There is a risk of acquiring a pet that is predisposed to various diseases.

In the video, a veterinarian talks about the disease feline cardiomyopathy.

Myocardial diseases are the most common acquired diseases in cats. They can be divided into several types of cardiac diseases.

Primary myocardial diseases: hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, unclassified cardiomyopathy, arrhythmogenic cardiomyopathy.
Secondary myocardial diseases occur with hypertension, hyperthyroidism, taurine deficiency (occurs when feeding natural food).

Primary myocardial diseases differ from secondary ones in that they do not have causes that cause these diseases.

Cardiomyopathies most often occur in Persian, Scottish Fold, British and similar breeds, Maine Coon, Siamese, Abyssinian, but can also develop in cats of any breed. Clinical signs are usually observed in predisposed cats around 5 years of age; in others over 10 years of age. Males get sick much more often than females, and symptoms can appear as early as 1 year of age.

Clinical manifestations include shortness of breath, exercise intolerance ( increased fatigue), open mouth breathing during emotional or physical activity. In advanced cases, failure of one or two hind limbs with a decrease in paw temperature.

But the disease can also be asymptomatic, until a heart murmur is detected during a routine examination. As a rule, cats are admitted to the clinic in the stage of decompensation, since the owners do not notice the gradually increasing exercise intolerance.

Hypertrophic cardiomyopathy characterized by compensatory hypertrophy of the ventricular myocardium without any obvious reasons.
Dilated cardiomyopathy characterized by left ventricular dilatation and diastolic dysfunction. At the same time, the internal diameter of the left ventricle increases and myocardial contractility is reduced.
Restrictive cardiomyopathy is not characterized by either dilatation or hypertrophy of the left ventricle, but it is accompanied by impaired filling of the left ventricle, which leads to dilatation of the left atrium.
Unclassified or intermediate cardiomyopathy is a term sometimes used to describe patients with multiple disorders, such as hypertrophy and diastolic dysfunction.

Arrhythmogenic right ventricular cardiomyopathy characterized by marked dilation and thinning of the walls of the right ventricle, many of them have arrhythmia.

To diagnose and differentiate diseases, instrumental methods are used, such as: chest x-ray, so that you can visually determine the size of the heart; echocardiography (ultrasound of the heart) to determine the structure of the heart and its functional state; electrocardiography when the doctor listens to an uneven rhythm.

Forecast

The main determining factors in cats are the presence or absence of clinical signs and the presence or absence of left atrial enlargement. Decompensated cats admitted for treatment have a risk of death in the near future.

Cardiomyopathy in cats.

Based on materials from the website www.icatcare.org

Additional Information:

Cardiomyopathy refers to any disease that affects the heart muscle itself. Cardiomyopathy is the most common disease and cause of heart problems in cats. Diseases heart valve, which disrupt the normal functioning of the heart, often found in people and dogs, are observed quite rarely in cats.

Cardiomyopathies are distinguished by the effect that the disease has on the structure and function of the feline heart muscle:

Hypertrophic cardiomyopathy(Hypertrophic cardiomyopathy, HCM). The most common form of heart disease in cats. It is characterized by an increase in the thickness (hypertrophy) of the wall of the heart ventricle. This reduces the volume of blood in the heart and prevents the heart muscle from relaxing properly between contractions.
Dilated cardiomyopathy(Dilated cardiomyopathy, DCM). It is characterized by stretching (dilatation) of the walls of the heart cavities, due to which the cat’s heart enlarges and cannot contract effectively.
Restrictive cardiomyopathy(Restrictive cardiomyopathy, RCM). It is characterized by a pronounced decrease in the extensibility of the heart muscle, an increase in its rigidity and a decrease in elasticity, which prevents the chambers of the heart from filling normally.
Intermediate cardiomyopathy(Unclassifiable, Intermediate cardiomyopathy, ICM). In this case, changes characteristic of several types of disease are observed, for example, hypertrophic and dilated.

Causes of cardiomyopathy in cats.

Although most cases of heart disease in cats have no known underlying cause, sometimes potential cause it is possible to establish why the veterinarian may need to conduct certain examinations. Possible reasons may include the following:

Secondary cardiomyopathy (caused by other diseases)
Hyperthyroidism (overactive thyroid gland)
Hypertension (high blood pressure)
Acromegaly (excessive increase in hormone production)
Nutrition problems
Taurine deficiency (causes dilated cardiomyopathy)
Infiltration of the heart muscle
Lymphoma (a type of malignant tumor)
Exposure to toxins
Some medications may cause side effects
Hereditary causes
Genetic defects characteristic of Maine Coons and other cat breeds. which can cause the development of cardiomyopathy

Symptoms of cardiomyopathy in cats.

In cardiomyopathy, changes in the heart (cardiac) muscle cause problems with heart function. Deviations in the functioning of a cat’s heart depend on the type of cardiomyopathy:

In hypertrophic and restrictive cardiomyopathy, the abnormalities are mainly associated with difficulties in relaxing the heart muscle between contractions. Diastole - a relaxed state of the heart muscle during the heartbeat in the interval between contractions, is not fully achieved, so the heart cannot effectively fill with blood. IN severe cases This leads to a problem with the cat's heart known as diastolic heart failure .

Dilated cardiomyopathy primarily affects a cat's heart's ability to contract (systole), reducing its ability to pump blood. In severe cases, this leads to disorders called systolic heart failure .

Early signs of heart disease in cats.

In the initial phase of the disease, cats may not show any signs and appear completely normal. In fact, many cats with cardiomyopathy Clinical signs may never appear. However, while in some cats the underlying disease develops slowly, in others the disease can progress very quickly.

Some early signs of heart disease can be detected during veterinary examinations of your cat, even before any obvious symptoms begin. This is one reason why it is recommended to have your cat examined annually (and older cats more often). Warning signs include the following:

Presence of a heart murmur. The veterinarian can detect abnormal murmurs by listening to the cat's heart through a stethoscope. The murmurs originate from areas of turbulence in the flow of blood passing through the heart.
Gallop rhythm. Normally, each heartbeat is accompanied by two sounds, distinguishable through a stethoscope - when the walls of the heart contract and relax. In case of heart disease, a third sound can be heard, which is called the “gallop rhythm”.
Deviations in contraction frequency. In some cases, heart disease in cats is accompanied by a significant increase or decrease in the frequency of contractions, while the heartbeat does not lead to the formation of normal blood flow (the heart beats, but no pulse is felt in the arteries).
Heart rhythm disturbances(cardiac arrhythmia). Normally, cats have a very uniform pulse, but with heart disease, interference may occur in the passage of impulses that control heart contractions, which leads to disturbances in the normal rhythm of the heart.

Many cats, especially in the early stages of disease, may have abnormalities that can only be determined by ultrasound examination of the heart. These cats show no clinical signs of heart disease, although many may develop signs in the future.

Heart failure in cats.

If the functioning of the heart is significantly impaired due to cardiomyopathy, it leads to heart failure (often called congestive heart failure), where the flow of blood into and out of the heart is impaired.

Clinical signs of heart failure can sometimes appear suddenly, and in some cats the condition worsens very quickly. Some cats may experience fainting, but this is relatively rare. Common symptoms include noticeable heart rhythm disturbances (which can lead to episodes where the cat's brain suffers from a lack of oxygen due to poor blood supply).

Unlike dogs, cats are not active at the same time (for example, while walking), so in cats, the decrease in activity often occurs unnoticed, masking early signs of heart disease. The cat simply gradually begins to spend more time resting and sleeping. Since cats hide illnesses well, and detect deviations in the early stages (especially without special examinations) is often difficult, obvious signs appear only after reaching a “critical point”, which can lead to the sudden or rapid development of quite severe conditions.

The most common sign of heart failure in cats is difficulty breathing - shortness of breath and/or rapid breathing (tachypnea). This is mainly caused by either fluid accumulation in chest cavity around the lungs (pleural effusion), or accumulation of fluid in the lungs themselves (pulmonary edema).

Along with difficulty breathing, cats experience cooling of the extremities (paws and ears), and pale mucous membranes (gums and eyes) caused by poor circulation. Occasionally, cyanosis (cyanosis) may be observed in the mucous membranes of the gums, eyes, and even on the skin. In rare cases, cats with heart disease may cough (although it is common in dogs).

Arterial thromboembolism in cats.

Another sign of heart disease in cats is Feline aortic thromboembolism (FATE). Sometimes it becomes the first indicator of developing heart disease. Thrombi (blood clots) may form in one of the heart chambers (usually the left atrium) of a cat with cardiomyopathy. This occurs mainly because blood cannot pass through the heart normally. A thrombus (or clot) is initially attached to the wall of the heart, but can be dislodged from there and enter the blood leaving the heart. Blood clots that enter the circulatory system are called emboli (from the Greek “embolas” - plug, wedge), hence the term “thromboembolism”. During circulation, such emboli can get stuck in small arteries and block blood access to certain parts of the cat's body. Although this may happen in different parts body, most often this happens at the ends of the main arteries (aortas) leaving the heart, where vessels emerge from them to supply blood to the hind legs. This complication is most often observed with hypertrophic cardiomyopathy, and leads to sudden paralysis one or both hind legs accompanied by severe pain.

Determination of the form of cardiomyopathy in cats.

To diagnose heart disease in cats, special examinations are carried out:

Electrocardiogram(ECG). The method allows you to track the electrical activity of a cat's heart. ECG can be very useful in detecting abnormal heart rhythms, but has limitations in use;
Radiography(radiography). The method allows you to identify changes in the size and shape of a cat’s heart, and track the accumulation of fluid (pleural effusion or pulmonary edema). Radiography can be used to monitor the results of treatment;
Ultrasound of the heart. Ultrasound examinations are very useful for diagnosis, as they allow you to see a three-dimensional image of the cat’s heart, determine the thickness of the walls and evaluate the contractions performed. Ultrasound helps to understand which part of the heart the murmur is coming from. By using ultrasound examinations You can quickly determine the type of heart disease in your cat. The procedure is usually not bothersome to the cat (it only requires shaving a small area of fur), so most cats undergo ultrasound without using sedatives and anesthetics;
Tests for identification of underlying diseases. Such examinations may be necessary in some cases, usually blood tests, blood pressure measurements, etc.

Treatment of cardiomyopathy in cats.

In general, the underlying cause of cardiomyopathy in cats is rarely treatable, but if the cardiomyopathy is secondary, due to a deficiency of taurine in the diet (which causes dilated cardiomyopathy), or due to diseases that cause hypertension (high blood pressure), or due to hyperthyroidism (overactive thyroid gland) - treatment of the underlying disease can have a positive effect on the functioning of the heart.

For feline heart failure, various medications have been developed to help relieve the cat's condition and control the disease. These include medications such as:

Beta blockers(similar to atenolol or propanolol) that lower the heart rate and reduce the oxygen demand of the cat's heart.
Diltiazem- a drug known as calcium channel blocker. Reduces the frequency and strength of heart contractions. This reduces the heart's need for oxygen and helps the heart relax between contractions.
Angiotensin-converting enzyme inhibitors(for example, benazepril, ramipril, enalapril) or angiotensin receptor blockers (telmisartan). The drugs help block the activation of the renin-angiotensin-aldosterone system - hormonal system, which stimulates heart disease in cats. Their use is useful in heart failure and probably also in the early stages of heart disease.
Pimobendan is a drug known as a diazo calcium channel sensitizer. It increases the force of contractions of the cat's heart and also has a dilating effect on the blood vessels, which promotes blood flow. Such drugs may be used to treat cats with congestive heart failure.
Diuretics(frusemide/furosemide and the like) are very useful against the development of signs of congestive heart failure by helping to remove fluid that accumulates in (or around) the lungs. The dose of drugs varies widely, depending on the result of their action.

Unfortunately, the true effectiveness of many medications for the treatment of heart disease in cats is not clear, since sufficient statistics have not been accumulated on them. clinical use. In addition, it should be understood that the drugs act different ways, and therefore can be useful in different situations. Basically, diuretics are used to combat the signs of congestive heart failure - with early diagnosis, it is possible to slow down or even stop the development of heart disease, providing the cat with good quality life.

Etiology

The cause of primary or idiopathic hypertrophic cardiomyopathy (HCM) in cats is unknown, but inherited pathology likely exists in many cases. The disease appears to be widespread in several breeds, such as Maine Coon, Persian, Ragdoll, and American Shorthair. There are also reports of HCM in littermates and other close relatives of domestic shorthaired cats. An autosomal dominant pattern of inheritance has been found in some breeds. It is known that there are many different gene mutations in people with familial HCM. Although some frequent mutations Human genes do not yet appear to be found in cats with HCM, but others may be found in the future. Some researchers (Meurs 2005) have also found a mutation in the myosin binding protein C of myocytes in this breed. Another mutation has been identified in ragdolls; testing for these mutations is currently available (www.vetmed.wsu.edu/deptsVCGL/felineTests.aspx).

In addition to mutations in genes that encode proteins responsible for myocardial contractility and regulatory proteins, possible reasons diseases include increased sensitivity of the myocardium to excess production of catecholamines; pathological hypertrophic response to myocardial ischemia, fibrosis or trophic factors; primary collagen pathology; disorders of myocardial calcium-related processes. Myocardial hypertrophy with focal mineralization occurs in cats with hypertrophic feline muscular dystrophy, which is an X-linked recessive dystrophic disorder similar to Duchenne muscular dystrophy in humans; however, congestive heart failure is uncommon in these cats. Some cats with HCM have high concentrations growth hormone in blood serum. It is unclear whether viral myocarditis plays a role in the pathogenesis of feline cardiomyopathy. In one study, myocardial samples from cats with HCM were assessed by polymerase chain reaction(PCR) and showed the presence of panleukopenia virus DNA in approximately one third of cats with myocarditis and did not show its presence in healthy control cats (Meurs, 2000).

Pathophysiology

Thickening of the left ventricular wall and/or interventricular septum is common, but the extent and distribution of hypertrophy is variable in cats with HCM. Many cats have symmetric hypertrophy, but some have asymmetric thickening of the interventricular septum and few have hypertrophy limited to the left ventricular free wall or papillary muscles. The left ventricular lumen usually appears small. Focal or diffuse areas of fibrosis occur in the endocardium, conduction system, or myocardium; narrowing of the small coronary arteries may also be present. Areas of myocardial infarction and misalignment of myocardial fibers may be present.

Myocardial hypertrophy and accompanying changes increase the rigidity of the ventricular wall. In addition, early active myocardial relaxation may be slow and incomplete, especially in the presence of myocardial ischemia. This further reduces ventricular compliance and promotes diastolic dysfunction. Ventricular stiffness impairs filling of the left ventricle and increases diastolic pressure. Left ventricular volume remains normal or decreases. Decreased ventricular volume causes decreased stroke volume, which may promote neurohormonal activation. More high frequency cardiac contractions further influence left ventricular filling, promoting myocardial ischemia, pulmonary venous congestion and edema, shortening the duration of diastolic filling. Contractility or systolic function is usually normal in affected cats. However, some cats gradually develop systolic ventricular failure and ventricular dilatation.

The progressive increase in left ventricular filling pressure leads to increased pressure in the left atrium and pulmonary veins. The result may be progressive enlargement of the left atrium and pulmonary congestion and edema. The degree of left atrium enlargement varies from mild to severe. Thrombi are sometimes found in the lumen of the left ventricle or attached to the wall of the ventricle, although they are more often localized in the left atrium. Arterial thromboembolism is a major complication of HCM, as well as other forms of cardiomyopathies in cats. Some affected cats develop mitral regurgitation. Changes in left ventricular geometry, papillary muscle structure, or systolic motion of the mitral valve (systolic anterior leaflet motion (SAM)) may prevent normal valve closure. Valvular regurgitation increases left atrial size and pressure.

Systolic dynamic obstruction of the left ventricular outflow tract occurs in some cats. This phenomenon is also called hypertrophic obstructive cardiomyopathy or functional subcardiomyopathy. aortic stenosis. Excessive asymmetric hypertrophy of the base of the interventricular septum may be evident on echocardiogram and at autopsy. Systolic outflow tract obstruction increases left ventricular pressure, adversely affects the ventricular wall, increases myocardial oxygen demand, and promotes myocardial ischemia.

Mitral regurgitation increases the tendency for the anterior mitral valve leaflet to move toward the interventricular septum during ventricular systole (SAM). Increased turbulence in the left ventricular outflow tract often causes a systolic murmur varying intensity in these cats.

Various factors likely contribute to the development of myocardial ischemia in cats with HCM. These include narrowing of the intramural coronary arteries, increased left ventricular filling pressure, decreased perfusion pressure in the coronary arteries and insufficient density of myocardial capillaries, depending on the degree of hypertrophy. Tachycardia promotes ischemia by increasing myocardial oxygen demand while decreasing diastolic coronary perfusion time. Ischemia impairs early active relaxation of the ventricles, which later increases ventricular filling pressure and, over time, leads to myocardial fibrosis. Ischemia can provoke arrhythmia and possibly chest pain.

Atrial fibrillation and other tachyarrhythmias further impair diastolic filling and increase venous stasis; Particularly harmful are the loss of normal atrial contractions and increased heart rate associated with atrial fibrillation. Ventricular tachycardia or other arrhythmias may lead to syncope or sudden death. Pulmonary venous congestion and edema are caused by increased left atrial pressure. Increased pulmonary venous and capillary pressure causes pulmonary vasoconstriction; Increased pulmonary arterial pressure and symptoms of secondary right-sided congestive heart failure may occur. Over time, some cats with HCM develop refractory biventricular failure with massive pleural effusion. The effusion is usually a modified transudate, although it may be (or become) chylous.

Clinical manifestations

HCM is most common in middle-aged male cats, but clinical signs can occur at any age. Cats with mild disease may be asymptomatic for several years. Symptomatic cats most often exhibit respiratory symptoms varying degrees severity or symptoms of acute thromboembolism. Respiratory symptoms include tachypnea; activity-associated shortness of breath; dyspnea and very rarely cough (which can be confused with vomiting). The onset of the disease may be acute in sedentary cats, even if pathological changes develop gradually. Sometimes lethargy and anorexia are the only manifestation of the disease. Some cats experience syncope or sudden death in the absence of other symptoms. Stresses such as anesthesia, surgical operations, fluid administration, systemic illness (eg, hyperthermia or anemia), or transport may precipitate heart failure in compensated cats. Asymptomatic disease is detected in some cats by detecting a heart murmur or galloping rhythm on routine auscultation.

Systolic murmurs caused by mitral regurgitation or left ventricular outflow tract obstruction are often detected. Some cats have no audible murmur, even those with severe ventricular hypertrophy. A diastolic gallop sound (usually S4) may be audible, especially if heart failure is evident or threatened. Cardiac arrhythmias are relatively common. The femoral pulse is usually strong. with the exception of cases of distal aortic thromboembolism. The heartbeat is often increased. Increased respiratory sounds, pulmonary rales and sometimes cyanosis accompany severe pulmonary edema. Crackles in the lungs are not always heard with pulmonary edema in cats. Pleural effusion usually attenuates ventral lung sounds. Physical examination may be normal in subclinical cases.

Diagnosis

Radiography

Radiographic features of HCM include enlargement of the left atrium and varying degrees of enlargement of the left ventricle. Classic look The valentine-shaped heart is not always present in dorsoventral and ventrodorsal views, although the position of the apex of the left ventricle is usually preserved. The cardiac silhouette appears normal in most cats with mild HCM. Dilated and tortuous pulmonary veins may be seen in cats with chronic increases in pulmonary vein and left atrium pressure. Left-sided congestive heart failure causes patchy infiltrates expressed to varying degrees with interstitial or alveolar pulmonary edema. Radiologically, the distribution of pulmonary edema is variable; A diffuse or localized distribution within lung fields is usually found, as opposed to the characteristic hilar distribution of cardiogenic pulmonary edema in dogs. Pleural effusion is common in cats with advanced or biventricular congestive heart failure.

Electrocardiography

The majority of cats with HCM (up to 70%) have electrocardiographic abnormalities. These include abnormalities characterized by left atrial and left ventricular enlargement, ventricular and/or (less commonly) supraventricular tachyarrhythmias, and signs of left bundle branch block. Atrioventricular conduction delay, complete atrioventricular block, or sinus bradycardia sometimes occur.

Echocardiography

Echocardiography is the best method diagnosis and differentiation of HCM from other diseases. The extent of hypertrophy and its distribution within the free wall of the left ventricle, interventricular septum and papillary muscles is revealed in M-mode and B-mode echo studies. Doppler ultrasound may demonstrate left ventricular systolic and diastolic abnormalities.

Widespread myocardial thickening is common, and hypertrophy is often asymmetrically detected in the left ventricular free wall, interventricular septum, and papillary muscles. Focal zones of hypertrophy also occur. Using B-mode helps ensure that the scanning direction is correct. Standard M-Mode measurements should be taken, but areas of thickening outside these standard positions should also be measured. Diagnosis at an early stage of the disease may be presumptive in cats with mild or only focal thickening. False-positive thickening (pseudohypertrophy) can occur with dehydration and sometimes with tachycardia. False diastole thickness measurements also occur when the ultrasound beam does not cross the wall/septum perpendicularly and when measurements are not taken at the end of diastole, which can occur without a simultaneous ECG, or when the use of B-mode is insufficient for a good measurement. A thickness of the free wall of the left ventricle or interventricular septum (correctly measured) of more than 5.5 mm is considered pathological. Cats with advanced HCM have a diastolic left ventricular septal or left ventricular free wall thickness of 8 mm or more, although the degree of hypertrophy does not necessarily correlate with the severity of clinical signs. Doppler assessments of diastolic function, such as isovolumic relaxation time, mitral inflow, and pulmonary venous velocity, as well as Doppler tissue imaging techniques, are increasingly being used to characterize disease.

Hypertrophy of the papillary muscles may be severe and obliteration of the left ventricle during systole has been observed in some cats. Increased echogenicity (brightness) of the papillary muscles and subendocardial areas is usually a marker chronic ischemia myocardium with resultant fibrosis. Left ventricular shortening fraction is usually normal or increased. However, some cats have mild to moderate left ventricular dilatation and reduced contractility (contraction fraction 23-29%; normal contractility fraction 35-65%). Sometimes there is enlargement of the right ventricle and pleural or pericardial effusion.

Cats with dynamic left ventricular outflow tract obstruction also often have mitral valve SAM or early leaflet closure aortic valve, revealed during examination in M-mode. Doppler ultrasound may demonstrate mitral regurgitation and turbulence in the outflow tract of the left ventricle, although the location of the ultrasound beam along the blood stream with maximum speed Ventricular ejection is often difficult and the systolic gradient is easy to underestimate.

Enlargement of the left atrium can range from mild to severe. Spontaneous enhancement (rotation, smoke echo) is seen within the enlarged left atrium in some cats. It is assumed that this is the result of blood stasis with cell aggregation and is a precursor to thromboembolism. Thrombosis is sometimes visualized within the left atrium, usually in its appendage.

Other causes of myocardial hypertrophy must be excluded before a diagnosis of idiopathic HCM is made. Myocardial thickening may also occur due to infiltrative disease. Variations in myocardial echogenicity or wall irregularity may be detected in such cases.

Excessive connective tissue looks like bright. linear echoes within the left ventricular cavity.

Clinicopathological features

Cats with moderate to severe HCM have high circulating concentrations of natriuretic peptides and cardiac troponins. In cats with congestive heart failure, plasma concentrations of tumor necrosis factor (TNF) have been found to be increased to varying degrees.

Picture 1

Radiographic findings in feline HCM. Lateral (A) and dorsoventral (B) views demonstrating left atrial enlargement and mild ventricular enlargement in a male domestic shorthair cat. Lateral view in a cat with HCM and pronounced edema lungs

Etiology and pathophysiology
The disease can occur at any age, but middle-aged animals (about 6.5 years) are most often affected. In males, the disease is more common (>75%). In humans, in 55% of cases there is hereditary predisposition to HCM. In humans, this pathology can be congenital or acquired, and probably represents a group of diseases.

Although the etiology of HCM in cats is unknown, a predisposition has been identified in Persian cats and Maine Coons in some cases, suggesting a possible genetic influence. Our laboratory conducted a case-control study, which revealed a trend towards predisposition in Maine Coons. These data were confirmed in a study by Muirs et al., who revealed an autosomal dominant pattern of inheritance of HCM in Maine Coons and Ragdoll cats. Of interest is the work of Kittleson and colleagues, where it was suggested that in some cases excessive secretion of growth hormone may be a likely etiological factor. Severe left ventricular hypertrophy is observed, among other things, in diseases such as systemic hypertension, hyperthyroidism and aortic stenosis. However the real reason LVH in hypertrophic cardiomyopathy has not been established.

Heart damage is characterized by significant concentric hypertrophy of the left ventricle and secondary dilatation of the left atrium. Asymmetric ventricular septal hypertrophy (AVS), which occurs in most dogs and humans with HCM, occurs in only 30% of cases in cats. Histological examination reveals a disordered arrangement of cardiomyocytes in 27% of affected cats. Moreover, these histological changes are characteristic only of animals with asymmetric hypertrophy of the interventricular septum. Other histologic features of HCM in cats include myocardial and endocardial fibrosis and narrowing of the coronary arteries. Dynamic obstruction of the aortic ostium, secondary mitral valve insufficiency, myocardial ischemia and systemic arterial embolism (SAE) can complicate the course of the disease.

The left side of the heart is predominantly affected. The disease manifests as sudden cardiac death or, more often, acute insufficiency left side of the heart as a result of diastolic dysfunction. In some cases, HCM may cause effusion in the pleural cavity. Systolic function is usually adequate or enhanced. Tilley and Lord found that cats with HCM exhibit increased resting left ventricular end-diastolic pressure (LVEDP). When isoproterenol is administered, which mimics the stress-mediated endogenous activity of the sympathoadrenal system, LVDP doubles. Left ventricular end-diastolic pressure corresponds to pressure in the left atrium and pulmonary veins, which reflects the risk of developing pulmonary edema. In addition, an increase in heart rate during stressful situations leads to a decrease in the filling time of the heart cavities and a deterioration in myocardial perfusion. As a consequence, there is a further decrease in the volume of the heart cavities. As a result, under conditions of increased heart rate and increased need in oxygen, relative myocardial ischemia and further worsening of diastolic dysfunction occurs. Stressful situations, such as being transported in a car, being restrained during an ECG test, a fight with a dog, or embolic complications, can provoke left heart failure and pulmonary edema.

Clinical manifestations
In most cases, HCM can be detected before the first clinical signs appear. For this purpose, ECG, chest x-ray and echocardiography are used. The attending physician should suspect the disease if a murmur, galloping rhythm, or abnormal heart rhythm is detected. On the other hand, a cat may die unexpectedly in the absence of any clinical manifestations. The most common clinical symptom is the sudden onset of shortness of breath. Difficulty breathing in some cases can be combined with signs of SAE (its prevalence ranges from 16% according to clinical trials up to 48% based on autopsy results). Upon examination, attention is drawn to the cat's fatness and the presence of shortness of breath. Auscultation reveals wheezing in the lungs, a heart murmur (in 50% of cases), usually louder in the apex region on the left, a gallop rhythm (40%, usually the fourth sound), and (or) heart rhythm disturbances (25-40% cases). Heart sounds may be muffled. There is pallor of the mucous membrane of the mouth; The pulse may be normal, weak or absent (SAE). There may be an increase in the apical impulse and, in rare cases, an enlargement of the liver. Cats with HCM are not characterized by the presence of hypothermia, which is important in the differential diagnosis of dilated cardiomyopathy (DCM).

Diagnostics
Diagnosing HCM is not difficult, but specialized tests are required to confirm the diagnosis. Without the help of echocardiography, it is difficult to distinguish HCM from dilated or restrictive cardiomyopathy (RCMP). Differential diagnosis with DCM is especially important, since the approach to treatment and prognosis for this disease are different. It is also necessary to exclude other diseases that are characterized by the development of hypertrophy of the left ventricle and interventricular septum. These include hyperthyroidism, systemic hypertension and aortic stenosis.

ECG changes occur in 35-70% of cases and provide valuable diagnostic information. Most ECG changes are not specific. Deviation electrical axis to the left and blockade of the anterior branch of the left bundle branch strongly suggest the presence of HCM. However, these changes are also observed in RCMP, hyperkalemia, hyperthyroidism, and, less commonly, in DCM.

Other ECG abnormalities include: P-mitrale and P-pulmonale (10% and 20% of cases, respectively), tall R waves (40%), wide QRS complexes (35%), conduction disturbances (50%, including deviation of the electrical axis to the left in 25% of cases and blockade of the anterior branch of the left bundle branch in 15%), as well as cardiac arrhythmias (55%, usually of ventricular origin).

On chest x-ray, HCM is characterized by the presence of cardiomegaly with enlargement of the left ventricle and atrium, as well as congestion and/or signs of pulmonary edema. In the ventrodorsal view, the heart has a “postcard heart” appearance and reflects concentric ventricular hypertrophy and enlargement of the left atrial appendage. In addition, the apex is often shifted to the right. In the lateral projection, an increase in the size of the heart and the area of its contact with the sternum is observed. There are also signs of left atrium enlargement, left ventricular rounding, and bulging of the caudal waist of the heart. In heart failure, in 25-33% of cases, effusion is detected in the pleural cavity, but its volume is significantly less than in DCM. In HCM, the risk of non-selective angiography is lower compared to DCM. During this manipulation, normal or increased circulation, tortuosity of the pulmonary veins, enlargement of the left atrium, a decrease in the lumen of the left ventricle and thickening of its wall, as well as an increase in the papillary muscles are revealed. The diagnosis of SAE (“saddle-shaped” thrombus is usually localized in the area of the aortic trifurcation) is confirmed by the presence of a break contrast agent in the area of trifurcation of the aorta.

Echocardiography is an extremely important tool for the differential diagnosis between HCM and DCM. However, due to overlap in reference values, distinguishing between conventional and asymptomatic HCM, or between HCM and RCMP, may be difficult. Concentric left ventricular hypertrophy and left atrial enlargement are important diagnostic features of HCM. Cardiac activity remains within normal limits or increases due to a decrease in afterload and the possible presence of hypercontractility. Obvious vibration of the anterior mitral valve leaflet during systole may indicate dynamic obstruction of the aortic orifice. AHMP, left atrial thrombi, and pleural and/or pericardial effusions may also be detected.

Recently, the promise of biomarkers in the diagnosis and prognosis of HCM has been revealed. Genetic markers developed by Muirs et al. have proven useful in identifying HCM in Maine Coon and Ragdoll cats. Cardiac troponin I is a component of the actin-myosin complex. An increase in its level in the blood indicates damage to myocardial cells and is used in the diagnosis of HCM. The level of natriuretic peptides (ANP and BNP) in the blood indicates an increase in circulating blood volume and (or) a decrease renal clearance hormones. N-terminal fragment of brain natriuretic peptide precursor (NT-proBNP) is used for disease detection of cardio-vascular system in cats (most often HCM), as well as for the differential diagnosis of heart failure. Despite the fact that these tests are at the research stage, their benefits are already noticeable. It is likely that these tests will be used more actively in the future.

In the case of sudden death, the diagnosis is made based on the results of an autopsy, during which typical gross pathology of the cardiovascular system and histological changes are revealed. Other laboratory findings, with the exception of hypotaurinemia, are similar to those seen in feline DCM. Differential diagnosis is also practically the same. It is necessary to exclude restrictive pericarditis, as well as systemic hypertension and thyrotoxic heart disease.

Clark Atkins, DVM,
Diplomate of the American College of Veterinary Internal Medicine (ACVIM) (internal medicine, cardiology),
State University North Carolina, USA

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

According to veterinary statistics, hypertrophic cardiomyopathy is diagnosed in 45% of 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 began in the early 2000s in the United States. A large population of Maine Coon and Ragdoll cats was scientifically analyzed for carriage of a mutation leading to heart disease.

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

Based on the research conducted, genetic test systems were created. However, their widespread use was not justified, since even with the selection of mutation-negative sires, cases of heart disease were encountered in the offspring.

By 2010, German scientists had 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 throughout the world, are reliable only for cat populations in the United States.

Causes of development of hypertrophic cardiomyopathy

Studying the causes leading to the development of heart disease in furry pets,
allowed us 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 the main cause of the development of the disease in domestic cats is gene mutations. Defects in the transmission of genetic information leading to hypertrophic cardiomyopathy most often occur in breeds such as Maine Coon, Ragdoll, Persian, Sphynx, and Abyssinian cats.

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

Among such popular breeds as 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 susceptible to secondary forms of the disease.

Besides genetic cause influencing the development of cardiomyopathy, veterinary specialists identify the following factors contributing to the disease:

Congenital pathologies of the myocardium in the form of thickening of the walls of the organ and an increase in its size - “bull” heart.
Endocrine diseases: overactive thyroid gland, acromegaly. Increased output thyroid hormones leads to tachycardia and worsens the trophism of the heart muscle. Increased production of growth hormone (acromegaly) leads to thickening of the walls of the heart.
Imbalance of the diet in terms of taurine. 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 disruption of the functional state of the heart muscle.
Constantly high blood pressure in a pet leads to wear and tear on the heart muscle.

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

What happens to a cat’s heart during pathology?

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

A defective gene results in the body being unable 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. In addition, connective tissue reduces the elasticity and extensibility of the heart. The pumping function of the organ weakens.

Thickening of the myocardium leads to the fact that blood stagnates in the atria and the functioning of the atrioventricular valve is disrupted. Aortic obstruction occurs and 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 explained by the fact that a spasm of the peripheral bloodstream occurs, and the pulmonary vessels become overfilled with blood. In a sick animal, blood clots form due to slow blood flow in the distended chambers of the heart.

Types of hypertrophic cardiomyopathy

In veterinary practice, it is customary to distinguish between primary and secondary cardiomyopathy. The primary form of the disease, which has a genetic predisposition, usually manifests itself before the animal is 5 years of age. The secondary form is most typical for older animals and is more often observed in cats over 7 years of age. This type of pathology develops due to diabetes mellitus, kidney diseases, endocrine system.

According to 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 non-obstructive form, there are no changes in the bicuspid valve.

Symptoms of cardiomyopathy in cats

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

The disease can occur in obvious and hidden forms in terms of the manifestation of clinical signs. If there is obvious pathology in the 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 low temperature– hypothermia.
Heavy breathing, shortness of breath. During active physical activity, the animal experiences difficulty in inhaling due to the slowing of blood flow in the pulmonary veins. The owner can observe how the cat begins to breathe rapidly, sticking out its tongue. Breathing movements In this case, they are performed not by the chest, but by the stomach.
Attacks of suffocation, loss of consciousness, fainting. Severe shortness of breath often ends with such symptoms due to oxygen starvation of the brain. The pulse is thread-like in nature.
Due to lack of oxygen, the mucous membranes become bluish (cyanosis).
A reflex cough is observed due to the pressure of the enlarged heart on the trachea. The animal takes a characteristic pose: leaning on all its limbs, stretches its neck and head forward. The front paws are widely spaced to better ventilation lungs.

and ascites. As a result of exudate, edema forms in the chest and abdominal cavity.
Paralysis of a cat's hind legs develops in advanced cases of the disease, when blood clots close the lumen of large blood vessels in the pelvic area.
Young animals gain poorly muscle mass, lag behind breed standards and their peers in development.

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

Diagnosis of hypertrophic cardiomyopathy

The difficulty of identifying cardiac pathology in a pet is due to the hidden nature of the disease and long absence clinical picture. A veterinarian may suspect problems with the myocardium 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, a veterinarian will usually order a chest x-ray, electrocardiography, and cardiac echocardiography.

X-ray examination can detect not only enlargement of the left ventricle and atrium, but also detect pleural effusion. ECG of the heart detects disturbances in its functioning in 70% of patients with feline hypertrophic cardiomyopathy.

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

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

For information about what echocardiography shows in cats with HCM, watch this video:

Treatment of hypertrophic cardiomyopathy in cats

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

Furosemide is used parenterally to reduce congestion and eliminate edema. The dosage and frequency of use is determined by a veterinarian based on an echocardiographic examination of the diseased organ.

Beta blockers have a good effect in the treatment of hypertrophic cardiomyopathy in cats. The drugs reduce heart rate and suppress tachyarrhythmias. Beta blockers reduce myocardial oxygen demand and 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 and 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 and given rest. The diet should be balanced primarily in terms of taurine content. On the recommendation of a veterinarian, the animal can be given the amino acid orally.

The forecast depends on the following factors:

timely detection of pathology;
manifestations of clinical signs;
severity of symptoms;
likelihood of pulmonary edema;
presence of thromboembolism.

Veterinary practice shows that cats with moderate enlargement of the left ventricle and atrium often live to an advanced age. In the presence of severe heart failure and congestion, the prognosis is cautious. Cats with significant hypertrophy of the heart muscle live 1 - 3 years. The prognosis is even more cautious, even unfavorable, with the development of thromboembolism.

Actions of the owner towards the animal upon confirmation of the diagnosis

Experienced breeders and veterinary specialists give the owner of a sick cat the following recommendations:

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

The prognosis for a sick cat is usually guarded. If hypertrophic cardiomyopathy is detected, experts recommend not allowing the animal to be bred.