Restrictive cardiomyopathy in a dog. Types of cardiomyopathy in dogs and how to treat it

therapist, visual diagnostics doctor

Dilated cardiomyopathy (DCM) - a disease of the heart muscle, accompanied by a violation of the pumping function of the heart with the development of congestive (chronic) heart failure.

Dilatation (from Latin dilatation) is an expansion, stretching of the chambers of the heart. With DCM, expansion occurs mainly in the left ventricle of the heart, and as heart failure develops, other chambers also expand. This is the most characteristic feature of the disease. In practice, DCMP is a thinning of the walls of the ventricles and atria due to the development of dystrophic processes in muscle fibers. As a result, there is a violation of their contractile function, systolic dysfunction develops - the heart contracts worse and ceases to eject a normal volume of blood into the vessels.

Dogs of large and giant breeds, mostly males, are predisposed to DCM. DCM is very common in Dobermans. In some cases, the disease is secondary and develops with other heart diseases (for example, myocarditis - inflammation of the heart muscle after infectious diseases) or with diseases of other organs.

DCM is a disease with an extremely severe course and a poor prognosis, and modern drug treatment is effective in the early stages. Therefore, the sooner a diagnosis is made and treatment is started, the easier it will be to control the development of the disease and prevent its complications, the longer and more fulfilling life your pet will live.

Diagnosis of the disease
The diagnosis of DCMP is made on the basis of data from clinical and additional research methods. Unfortunately, this disease can be asymptomatic for a very long time. If your dog has become tired faster, it is a reason to see a doctor. It is important to understand that many diseases are accompanied by lethargy, but if heart failure is suspected, even a therapist can take a chest x-ray and detect a deviation from the norm. If necessary, you will be sent to a cardiologist who will take an ECG, do an ultrasound of the heart (echocardiography) to make an accurate diagnosis and prescribe therapy. In a serious condition of the animal, even hospitalization may be required - inpatient treatment.

Symptoms of DCMP are weakness, fatigue, exercise intolerance, shortness of breath, cough.
Very characteristic of DCM are periodic attacks of acute heart failure, which can lead to sudden death of the animal. They are accompanied by a sharp development of general weakness, up to loss of consciousness with convulsive syndrome (syncope), frequent breathing with an open mouth, pallor or blue mucous membranes. The cause of these attacks are severe cardiac arrhythmias that complicate the course of DCM. Arrhythmias occur due to damage to the normal structure of the heart muscle, which creates favorable conditions for disrupting the processes of occurrence and conduction of an electrical impulse and excitation of muscle fibers. With DCM, various forms of ventricular arrhythmias often develop, including life-threatening ventricular tachycardia, up to ventricular fibrillation. In addition, more than half of dogs with DCM develop atrial fibrillation.

Another very serious complication of DCM is pulmonary edema accompanied by acute respiratory failure. A condition that, if timely medical care is not provided, causes the death of an animal. In addition, the impaired pumping function of the heart often leads to the accumulation of fluid in the chest and abdominal cavities.

Medical treatment
Treatment of DKMP is carried out under the strict supervision of a veterinarian. The main areas of treatment for DCM are: Slowing down the development of chronic heart failure, reducing the activation of neurohormonal systems, combating fluid retention in the body, enhancing the contractile function of the heart, controlling arrhythmias and preventing the formation of blood clots in the heart cavities. Timely and regular intake of drugs is very important, some of them work only with constant use. These drugs cannot stop the disease itself. Once every few months, the selected scheme needs to be adjusted. Therefore, you need to regularly call or meet with your cardiologist.

This disease is defined in a separate group, because this breed has its own characteristics: anatomical and physiological.

Dobermans are unique dogs, courageous, patient, grateful to a person for attention and care, unfortunately, very "secret" - they show clinical symptoms already at a late stage of the disease. They are active until the last minute, when it becomes very difficult and unbearable due to a disease called dilated cardiomyopathy.

Updated information on the genetic status of the Doberman breed regarding DCM, March 12, 2017, Dr. Carol Beuchat - Scientific Director of the Institute of Canine Biology.

“The Doberman breed is in serious danger. About 60% of its representatives suffer from dilated cardiomyopathy (DCMP), 13% of which are affected by this disease by 6 years, and more than 40% by 8 years. …

In 1990, DCM was quite high - more than 25% of dogs were infected. Since then, the percentage of pathology has increased significantly, by about 1.5% per year. At this rate, by 2040, 100% of the Doberman breed will be affected by DCM. …

DCMP is fatal. Sometimes cardiac arrest occurs in the absence of any symptoms, the dog just drops dead. This can happen both during active play or running, and during separation from the family, when everyone is at work during the day, at school. Most dogs die in their prime and even younger. … »

The term "cardiomyopathy" is intended to refer to diseases in which the heart muscle is affected, in the absence of signs of inflammation.

There is a genetic predisposition of Doberman dogs to DCM, and this disease can also develop as a result of exposure to toxins and infections and amino acid deficiencies (mostly proven pathological consequences of taurine and L-carnitine deficiency).

How the disease manifests itself

As a rule, changes begin very long before the onset of clinical signs. When the owners report coughing, shortness of breath, an increase in the shape of the abdomen, this means that all systems and organs in the body are already involved in a serious pathological process!

During the examination, changes in the radiographic boundaries of the heart are revealed: it has a stretched spherical shape. As a rule, all four chambers of the vital organ are dilated.

At post-mortem autopsy, the vital organ is dilated, pale, soft, and droopy, and the heart/body weight ratio is usually elevated.

Clinical symptoms

In dogs, the pathology is characterized by an asymptomatic course for a long period (from 2 to 4 years), there are no clinical signs, and at the same time, the myocardium is already undergoing significant changes: thinning of the fibers, deterioration in contractility, rhythm disturbances, and expansion of the heart chambers.

The affected myocardium cannot create the pressure necessary to maintain the cardiac output.

Common manifestations of DCM:

• cough;
• apathy, lack of physical endurance;
• weakness;
• lack of appetite;
• weight loss;
• dyspnea;
• enlarged abdomen.

Males get sick more severely than females. Pathology in the first appears earlier (from 8 months to 2 years) than in bitches (from 5 to 7 years). Sudden death occurs in 25% of dogs of this breed, predominantly in males.

Life expectancy after diagnosis is also short: it is 4-6 months, subject to treatment.

The prognosis for this disease is poor.

The purpose of therapy: to maximize the improvement of heart function, to slow down the processes of myocardial remodeling and its destruction, to eliminate the symptoms of systolic and diastolic overload of the heart, to maximize the patient's quality of life.

How is dilated cardiomyopathy diagnosed?

X-ray diagnostics reveals an increase and expansion of the boundaries of the heart, venous congestion in the lungs. All signs found on the picture are not specific for DCM.

The electrocardiogram is informative, because it allows you to identify signs of an increase in the heart, arrhythmia. Atrial fibrillation is more common and especially life-threatening - ventricular arrhythmias. Dobermans are the only breed able to live with ventricular arrhythmias for years without any clinical symptoms. Although this is a huge risk group for the threat of sudden cardiac arrest.

Arrhythmia in a dog suffering from DCMP (Doberman, male, 2 years old).

ECG of a Doberman dog suffering from DCMP (Doberman, female, 8 years old).

The ECG clearly shows expansion of the P-interval and QRS complex, indicating dilatation of the left cavities. Increased P voltage and QRS complex in lead I, indicating dilatation of the right heart cavities

A blood test can reveal the presence of anemia, an increase in ESR, and according to biochemistry: reduced albumin, an increase in AST, ALT enzymes, reduced Na and Ca, an increase in CPK, LDH. Specific markers for heart failure in veterinary medicine are still in the experimental phase.

The results of the echocardiogram are final for establishing the diagnosis. Ultrasound signs of DCMP are very specific.

Based on the results of an echocardiogram, the diagnosis can be established or refuted.

During the examination, dilatation of the heart chambers is detected with unsatisfactory contractility of the ventricles and thinning of the interventricular septum, the posterior wall of the left ventricle.

Dobermans have their own norms of echographic indicators - dogs of this breed have the lowest level of left ventricular shortening fraction (the level of myocardial contractility). It should not be lower than 13%, while in other breeds with such contractility, fainting or cardiac arrest will occur.

Thinning of the walls of the myocardium and expansion of the cavities of the heart.

The most characteristic echocardiographic signs of DCM are significant LV dilatation with normal or reduced wall thickness.

ECHO procedure of a dog suffering from dilated cardiomyopathy - pronounced thinning of the interventricular and interatrial septum with dilatation of all four chambers of the heart.

In the later stages of the development of the disease, free fluid in the pleural and abdominal cavities can be detected on ultrasound.

Lungs, pleural effusion, seen through the heart.

Dilated intrahepatic veins. A list of other indicators includes an increase in the systolic and diastolic diameters of the left ventricle, reduced wall thickening in the systole phase, and increased separation of the E septum.

We leave the details of echocardiography to the fate of diagnostic specialists.

Veterinary cardiologists base their diagnosis on the recommendations of the European Veterinary Society of Heart Failure Specialists.

Holter monitoring is the recording of an electrocardiogram within 24 hours using a Holter monitor.

What are the Holter criteria:

The Holter recording must be of sufficient length (at least 23 hours of recording), of good quality, and must be accurately analyzed by a cardiologist. The automatic analysis of the Holter recording is obviously inaccurate and its manual correction is always necessary. Inaccurate Holter records can lead to both false positive and false negative results, which can have a significant negative impact on animal breeders and owners.

Fewer than 50 single ventricular premature beats are considered normal in Dobermans, although the detection of any number of ventricular premature beats is cause for concern. More than 300 ventricular extrasystoles within 24 hours or 2 subsequent records within a year showing between 50 and 300 ventricular extrasystoles within 24 hours are considered as occult dilated cardiomyopathy in Dobermans despite concurrent echocardiographic findings.

Many studies have used >100 ventricular extrasystoles per 24 hours as the lower limit for the diagnosis of DCM, but the authors believe that the results of a recent study should be the basis for current recommendations.

In dogs of large breeds, as well as older animals, heart problems are not uncommon. In this they are similar to humans. As a result, cardiomyopathy in dogs annually claims the lives of hundreds and even many thousands of pets around the world. This article will consider the classic clinical picture, as well as the symptoms of this disease.

The term "cardiomyopathy" refers to the state of pathological changes in the heart muscle, when the latter loses its normal functionality. It happens primary and secondary. Accordingly, in the first case, the disease develops due to some kind of congenital. But this doesn't happen all that often. Much more common cases of cardiomyopathy against the background of some diseases of viral, bacterial or fungal etiology.

In total, the following four types of pathology are distinguished, each of which is characterized by certain “transformations” of the heart tissue:

• hypertrophic type. Perhaps the most "physiological".
• Dilated cardiomyopathy in dogs.
• Restrictive.
• Mixed variety.

And what do all these terms mean? Let's find out! So, hypertrophic cardiomyopathy. Why do we call this state "physiological"? The fact is that in this case the organ increases almost symmetrically: not only its size increases, but also the thickness of the walls of the ventricles and atria. In principle, exactly the same process is typical for athletes ... So what's wrong with that?

And the bad thing is that this hypertrophy is not justified in any way from the point of view of the canine body. If the dog is old, he already lacks the strength and energy that needs to be spent on maintaining the efficiency of an overgrown heart! In addition, due to the exorbitant increase in muscle mass, the volume of the chambers of the ventricles and atria is reduced, as a result of which the organ itself begins to receive many times less nutrients and oxygen.

This leads to when some part of the heart muscle is necrotic. In the most severe cases, this causes sudden death of the animal.

Read also: Tachycardia in a dog. When the "fiery engine" is at its limit

Other varieties

Perhaps the most common type of pathology is dilatation. Often it comes to replace hypertrophy. What it is? Imagine a rag dangling in the water column ... An amorphous, unstable formation resembling a jellyfish. Now imagine that the heart wall has a similar texture. Can such a structure contract normally? Of course not. There are severe conditions of hypoxia, the dog cannot walk even a hundred meters, so as not to start to choke. Such animals do not live long, the prognosis is unfavorable.

However, restrictive cardiomyopathy also does not lead to anything good. With this pathology, fibrous fibers form in the thickness of the heart tissue. To put it simply, the organ turns in its properties into a kind of analogue of cartilage. It is easy to understand that such a heart practically cannot contract, and the animal, in addition to severe hypoxia, also receives severe, constant pain in the chest.

Finally, with mixed cardiomyopathy, everything can be observed at once. Of course, the situation when one ventricle is hypertrophied, the second is enlarged, and fibrosis has begun in the atria is in reality hardly probable, but a combination of hypertrophy and fibrosis is quite possible.

In addition, in rare cases, improper feeding leads to the development of this pathology, when the food lacks essential trace elements and vitamins. In particular, such an outcome is very likely if there is no selenium, vitamin B12 and E in the feed. However, in reality this happens relatively rarely and is more typical for those regions of our country where people experience similar problems.

Read also: Yeast dermatitis in dogs: symptoms, diagnosis, treatment

Clinical picture

What are the symptoms of cardiomyopathy in dogs? There are no specific signs, since the symptoms correspond to the clinical picture of heart failure. Symptoms of right ventricular failure may include: abdominal distension due to ascites, jugular venous congestion, hepatomegaly. The development of pleural effusion is fixed, hydrothorax may occur. With damage to the left ventricle, a cough occurs due to pulmonary edema, and tachypnea. In all cases, the dog is lethargic, gets tired quickly, a “galloping” pulse is recorded, pallor of all visible mucous membranes, an increase in capillary filling time, and cyanosis. The limbs (especially in older dogs) are constantly cool, the animal quickly loses weight.

In addition, a sick pet refuses food, he is lethargic and lethargic. Older dogs, among other things, develop a chronic, "barking" cough, which often cannot be brought down by specific drugs.

Why is this disease dangerous?

Whatever variety cardiomyopathy belongs to, for whatever reason it develops, it all comes down to one thing: a deterioration in blood circulation in the small and large circles of blood circulation. When the heart muscle is not working properly, it results in left- or right-sided congestive heart failure. In severe cases, all this is fraught with fainting, apathy, sometimes animals fall into a coma.

All these factors gradually exhaust the compensatory possibilities of the body. Ventricular extrasystoles often lead to sudden death, especially Doberman is predisposed to this pathology. Fibrillation is found in all dogs, regardless of their natural affiliation.

Therapy

Usually this disease is not treatable (especially in the variant of the primary disease). Complete recovery of the body is also unlikely. The main goals of treatment are to alleviate the clinical symptoms of heart failure and increase the remaining life. The therapeutic technique itself depends on the severity of the clinical picture. As a rule, furosemide and other diuretics are used in any case, as they help prevent the development of congestion. These include, among other things, pulmonary edema, which often leads to death if it occurs.

Veterinarians share that in recent years, the most common heart disease is dilated cardiomyopathy. Among dogs, it affects from 10 to 15%. Now more advanced diagnostic methods and the disease are detected in more animals.

DCMP is severe. If the disease is detected at an early stage, then it can be cured, otherwise, the dog remains to live out his life, struggling with the disease.

About the disease

In DCM, the myocardium is primarily affected. Dilatation of the cavities and impaired systolic functioning of the ventricles is pronounced. Veterinarians diagnose DCM when palpable dilatation of the cavities does not appear due to abnormalities in the coronary circulation or congenital pathology of development, bad heart valves, pericardial disease, systemic and pulmonary hypertension of the arteries.

Video about dilated cardiomyopathy:

Who is most often affected by the disease?

If the dog is large or its breed is giant, then the risk of developing heart disease is high. At risk are:

1. Dobermans.
2. Molossians.
3. Irish wolfhounds.
4. Newfoundlands.
5. german shepherds
6. Boxers.
7. Dogs.
8. Labradors.
9. Cocker spaniels are average, but also suffer from DCM.

This disease can be transmitted genetically, for example, autosomal dominantly in Newfoundlands, with Dobermans and Boxers. Autosomal recessive in Portuguese water dogs. Recessive (X-chromosomal type) in Great Danes. Males get sick 2 or 3 times more often than females. DCM most commonly affects pets in middle age or when they become older.

About symptoms and complications

Consider the main symptoms of DCM:

• high fatigue;
• dyspnea;
• cough;
• frequent weakness;
• The dog does not tolerate physical activity well.

In DCM, a dog has seizures that cause acute heart failure. Because of this, the pet may suddenly die. The animal feels weak, may lose consciousness, convulsions will appear. The dog will breathe often, for which he will open his mouth. It will be noticeable that the mucous membranes in the mouth have become blue and pale.

Attacks occur due to the fact that the heart rhythm is disturbed. This complicates the disease DKMP. Arrhythmia in pets happens when the heart muscle has damage in its structure. Violations occur when an electrical impulse goes and muscle fibers are excited.

When a dog is sick with DCM, various forms of arrhythmias can develop in the ventricles of the heart. Risk to life occurs with ventricular tachycardia. With this pathology, even ventricular fibrillation occurs. In DCM, 50% of dogs will have atrial fibrillation.

Bad symptoms are when the lungs swell in DCM. The dog will develop acute respiratory failure. If, with such a complication, the dog is not urgently shown to the veterinarian, if treatment is not started, it will die. When the heart is not working as a pump, fluid accumulates in the peritoneum and chest cavity. This also leads to the death of the animal.

Dilated (dilating) cardiomyopathy is a disease characterized by impaired pumping function and myocardial contractility. Accompanied by the expansion of the chambers of the heart, thinning of the walls of the ventricles of the heart, rhythm disturbances and stagnant processes in the body. Dilated cardiomyopathy in dogs is more common among large and giant breeds, predominantly in males. It is divided into primary - the etiology has not been completely studied, and secondary, the causes - other pathologies. Dilated cardiomyopathy in dwarf dog breeds is much less common, they are more likely to suffer from valvular defects.

Causes of DCM in dogs

The causes of primary dilated cardiomyopathy are not fully understood, presumably, taurine and L-carnitine deficiency play a role in the development of the process. The genetic conditionality of pathology in boxers and some other breeds has been proven.

Causes of secondary dilated cardiomyopathy:

• Myocarditis.
• Violations of the coronary circulation.
• Pathology of the valvular apparatus.
• Severe metabolic disorders.
• infectious diseases.
• Systemic inflammatory processes.
• Poisoning.
• Overdoses and side effects of toxic drugs.

Symptoms of DCM in dogs

Often the initial stages of the disease are asymptomatic, their development lasts for months, and sometimes years. In such cases, DCM is diagnosed mainly by chance, during an ultrasound of the heart. Clinical signs of the disease can develop both slowly and over a short period of time. Often there is sudden death, which was not preceded by any symptoms.

Characteristic signs of DCMP:

• Shortness of breath and increased fatigue after minor physical exertion or stress.
• Drowsiness.
• Cough.
• Paleness of mucous membranes.
• Weight loss with a simultaneous increase in the volume of the abdominal cavity (abdominal dropsy).
• Attacks of severe weakness, up to loss of consciousness.
• Periodic seizures.
• In severe cases, gurgling breathing develops with pulmonary edema.

A preliminary diagnosis is made on the basis of a physical examination, to clarify it, they carry out:

• Chest X-ray.
• Ultrasound (echocardiography) of the heart.

For a timely diagnosis, owners of dogs of large and giant breeds should consult a veterinarian at the first signs of DCM - weakness, fatigue and shortness of breath.

Dilated cardiomyopathy in dogs treatment

If a latent form of DCM is detected, the animal is prescribed antihypertensive drugs (most often ACE blockers), beta-blockers, diuretics, anti-arthmic drugs (in the presence of tachyarrhythmias).

With the development of acute heart failure against the background of DCM, emergency therapy includes:

• Intravenous administration of furosemide.
• Use of nitroglycerin ointment or spray or sodium nitroprusside infusion.
• Inotropic support (digoxin, dopamine).
• Keeping an animal in an oxygen chamber.
• The use of sedatives in case of severe anxiety.
• In the presence of fluid in the pleural cavity, a thoracocentesis is performed and the effusion is pumped out.

The introduction of new drugs and changes in dosages should be carried out carefully, with constant monitoring, since the condition can worsen very quickly.

Long-term therapy includes oral administration:

• Furosemide (in combination with potassium preparations) or veroshpiron.
• ACE inhibitors (captopril, enalapril). They should be used with caution in combination with potassium preparations, as there is a risk of hyperkalemia.
• Vetmedin or digoxin - are prescribed for supraventricular tachyarrhythmias and atrial fibrillation.
• Preparations with a high content of L-carnitine, taurine, omega 3 fatty acids.
• Beta-blockers - metoprolol, carvedilol.

Taking drugs continues for life, with constant monitoring of the condition and dosages. At the beginning of treatment, examinations are carried out 2-3 times a week, after stabilization of the condition and selection of effective doses - once every 2-3 months. It is necessary to reduce the salt content in the diet and strictly dose physical activity, to prevent exposure of the dog to stress factors.

A surgical treatment has been developed - the installation of elastic supporting structures that improve myocardial contractility and prolong its functional activity.

Forecast

Depending on the stage of the disease and the general condition of the animal, the prognosis ranges from cautious to unfavorable. With symptoms of congestion in the lungs, life expectancy depends on the initial response to treatment. In its absence, dogs rarely live more than 3-4 months. If the initial response to treatment is good, then the animal can live 6-12 months or more. In the case of a diagnosis at an early stage and the appointment of adequate therapy, life expectancy increases to 3-4 years or more.

In our clinic, the detection of cardiac diseases is carried out by veterinary cardiologists who have extensive experience working with dogs and cats. Also, our veterinary clinic is equipped with all the necessary equipment for the examination of cardiac patients.

Cardiological examination and reception are conducted by doctors - Biryukova Lidia Mikhailovna and Evstifeeva Olga Vladimirovna.

You can make an appointment with them by calling the clinic.

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