Endocardiosis of the atrioventricular valves in dogs. Mitral insufficiency Mitral valve endocardiosis Severe congestive heart failure

Among cardiac diseases in dogs, malformations in the development of the myocardium are one of the most common ailments and account for about 12% of all cardiac disorders. Veterinarians distinguish between congenital and acquired forms of the disease.

Early diagnosis of cardiac anomalies is difficult due to the absence of obvious clinical signs in the initial stages of the pathology. In addition to conservative therapy, modern veterinary medicine has proven surgical methods for correcting heart defects.

Veterinarians believe that the main causes and predisposing factors for the development of heart disease in dogs are:

• predisposition of animals at the gene level;
• developmental pathology in the prenatal and postembryonic period;
• intoxication, poisoning with poisons and household chemicals, the use of drugs, anti-inflammatory drugs during pregnancy of the bitch;
• inflammatory heart disease - endocarditis, pericarditis.

• injuries, mechanical damage to the chest;
• neoplasms in the myocardium.

Certain breeds of dogs are more susceptible to certain heart defects. For example, mitral valve dysplasia is more common in German Shepherds and Collies. Breeds such as the Rottweiler, Yorkshire Terrier are susceptible to non-closure of the Botallov duct. The English bulldog, boxer often has a defect of the interventricular septum.

Types of cardiac pathologies

In veterinary cardiology, it is customary to distinguish between congenital and acquired myocardial defects in dogs. The proportion of congenital ailments is 5% of the total number of diagnosed disorders of the valvular apparatus of the heart. Congenital anomalies appear at an early age and often end in the sudden death of a puppy. Acquired defects appear in dogs older than 6 years.

The most common pathologies in the work of the heart muscle include:

Pathology of the arterial duct is recorded in 30% of cases. Collies, poodles, German and Central Asian shepherds, Rottweilers are subject to congenital ailment.

• Narrowing of the opening of the pulmonary artery. Pathology occurs in 20% of cases and is characterized by valvular (narrowing of the valve leaflet ring) and subvalvular (narrowing of the lumen) in nature. The pathology is asymptomatic. Pulmonary artery stenosis is more commonly diagnosed in dog breeds such as the Beagle, English Bulldog, and Boxer.
• Stenosis of the aortic mouth. The anomaly is the third most common in dogs. Boxers, Labradors, Shepherds, Bull Terriers are susceptible to the disease. Aortic stenosis is manifested by the subvalvular nature of the pathology.
• Ventricular septal defect. The disease is due to the fact that the anatomical connection between the ventricles of the heart is preserved, as a result of which mixing of venous and oxygenated blood occurs. Bulldogs, Boxers and Dobermans are susceptible to the disease. Significant defects lead to mortality at an early age.
• Open oval window is an atrial septal defect. The pathology is caused by the preservation of the embryonic connection between the atria. The disease is rarely diagnosed in dogs. Poodles and boxers are subject to birth defects.
• Anomalies of the aortic arch. The defect is due to the anatomical pathology of the location of the largest vessel relative to the esophagus. The most common defect is observed in German Shepherds and Labradors.
• One of the severe heart defects in animals is Fallot's tetrad. The disease is a complex of defects (stenosis of the mouth of the pulmonary artery, changes in the anatomical position of the aorta, ventricular hypertrophy, anomaly of the interventricular septum) and is a common cause of death in puppies at an early age. Keeshonds and English Bulldogs are prone to congenital pathology. Life expectancy rarely reaches 1 year.

• mitral valve insufficiency characteristic of bull terriers and German shepherds. Dysplasia of the valvular apparatus leads to the reflux of blood into the left atrium with the development of left-sided chronic heart failure. Severe malformation has a poor prognosis.

• Tricuspid valve insufficiency manifested in the reflux of blood into the right atrium due to deformation of the valvular apparatus. The defect is accompanied by congestion in the systemic circulation. Boxers and Labradors are susceptible to the disease.

Veterinarians note that valvular defects are more common in young animals. The prognosis in such cases is usually unfavorable. In older pets, aortic and pulmonary stenosis are most common. Most often in veterinary practice, combined defects are observed.

For more information about heart disease in dogs, see this video:

Disease symptoms

Each specific defect in the development of the heart muscle is accompanied by certain clinical signs. In general, the symptoms of heart disease in dogs are as follows:

• Young growth lags behind in growth and development. Weak set of muscle mass. The lag in terms of live weight from breed standards.
• Lethargy, apathetic state of the animal.
• Muscle weakness. The dog reluctantly and with difficulty climbs the stairs, avoids active games. The usual training exercises are given to the pet with difficulty.
• Due to the slowing of blood flow through the vessels, edema is observed.
• Dyspnea. The symptom is characteristic of non-closure of the Botallian duct, insufficiency of atrioventricular valves and is caused by congestion in the lungs due to impaired blood supply.

• Chronic cough, . The sign develops due to a pathological increase in the size of the heart, as well as the accumulation of tissue fluid in the lungs.
• Cyanosis. The cyanosis of the mucous membranes and skin is due to oxygen starvation of tissues and organs due to disruption of the myocardium.
• Violation of the heart rhythm - bradycardia or tachycardia.
• The phenomena of aspiration pneumonia - cough, shortness of breath, wheezing are characteristic of anomalies in the development of the aortic arch.
• , hydrothorax. The accumulation of fluid in the chest and abdominal cavity due to stagnation of blood in the heart chambers.

• Violation of the rhythm of the pulse - arrhythmia, thready pulse.
• Fainting, loss of consciousness. Signs are associated with arrhythmia of the heart muscle and a decrease in blood flow to the aorta.
• Paresis of the forelimbs. The symptom develops as a consequence of thrombotic pathologies.

The clinical picture depends on the severity of the defect and the possibility of its compensation. Many congenital anomalies may not appear for years, without arousing suspicion in the owner, and only sudden death will be the result of many years of pathology. Often, a congenital malformation is detected only during preoperative cardiological examination.

Diagnostic methods

If you suspect a pathology of the pet's heart, you should show it to a veterinarian-therapist or cardiologist. At the appointment, the specialist will conduct a general clinical examination of the dog, percussion and auscultation of the heart area, examination of the femoral artery. On palpation of the heart, as a rule, an increased cardiac impulse is detected.

Auscultation allows you to identify and interpret systolic murmur, arrhythmias, the nature of atrial fibrillation. The method allows to detect atrioventricular blockade, regurgitation in the mitral and tricuspid valves. An experienced cardiologist will not only detect organic systolic and diastolic murmurs, but also determine the nature of the lesion, taking into account their projection.

The second stage of cardiological examination is the use of hardware diagnostic methods. In veterinary practice, X-ray examination is widely used to detect defects in the structure of the myocardium. The method allows assessing the size and shape of the heart, identifying the condition of the pulmonary vessels, and determining the anatomical location of the aortic arch. The examination helps to identify the phenomena of congestive heart failure, to assess congestion in the lungs.

More valuable information about the state of the heart muscle is provided by electrocardiography (ECG). The examination allows to identify arrhythmias, pathology in the structure of the atria, ventricles, the state of the mitral valve cusps, ischemic phenomena in the myocardium, congestion in the lungs.

The use in veterinary medicine makes it possible to detect a violation of blood flow in the organ, evaluate the work of the left and right ventricles, and the severity of heart defects.

Often, an ultrasound examination of the myocardium is used as a diagnostic study. Ultrasound of the heart allows you to evaluate the structure of the valves and heart vessels, determine the accumulation of fluid in the pericardium and chest, and identify the presence of birth defects.

If you suspect an anomaly of the aortic arch, the dog is assigned contrast esophagography.

Is it possible to treat congenital and acquired defects

The choice of treatment tactics depends on the type and severity of cardiac pathology. Defects such as non-closure of the Botalov duct, anomaly of the aortic arch, stenosis of the pulmonary artery orifice with the development of veterinary surgery are successfully corrected by surgical intervention.

In the event that the pet has a compensated defect, then, as a rule, no special treatment is required. It is enough to keep calm, reduce physical activity, transfer the dog to low-volume, easily digestible food.

The diet should be enriched with vitamins and minerals. Veterinarians recommend paying attention to the normal functioning of the intestines, avoiding atony in the pet.

Decompensated heart defects require drug therapy to prolong the life of a pet for many years. A veterinarian-cardiologist, according to indications, may prescribe cardiac glycosides, for example, Korglikon, Digoxin, obtained from plant materials - foxglove. The therapeutic effect of drugs is associated with contraction of smooth muscles and narrowing of blood vessels.

The complex therapy of heart defects includes the use of beta-blockers and antiarrhythmic drugs. The former have an anti-ischemic effect on the heart muscle. For this purpose, Anaprilin, Atenolol, Bisoprolol are used. Successfully cope with arrhythmia Lidocaine, Sotalol.

Antiarrhythmic drugs

If the dog has edema, diuretics are prescribed, for example, Furasemide. The animal is transferred to a salt-free diet. With congestion in the lungs, Eufillin is prescribed.

Drug therapy for decompensated defects is prescribed, as a rule, for life and can significantly increase the life expectancy of a pet.

Prevention

It is not possible to completely exclude the risk of congenital anomalies in dogs due to the polyetiological nature of the pathology.

The owner can minimize the appearance of a defect by following the recommendations of veterinary specialists in matters of proper care and proper feeding of the dog, taking into account the physiological periods of life.

Regular screening of cardiac examinations will help early diagnosis of heart disease.

Heart disease in dogs is not uncommon. The cause of congenital anomalies is often a genetic predisposition. Without surgical correction, in most cases, such defects end up fatal for the pet. Decompensated defects require lifelong complex therapy aimed at reducing the symptoms of heart failure. Modern veterinary medicine has high-tech methods for the rapid solution of cardiac pathologies in dogs.

Characteristics.
It is expressed in the incomplete closure of the valve leaflets and, as a result, the reverse flow of blood in the atrium. Of the acquired heart diseases, this is the second most common pathology.

Etiopathogenesis.
The etiology of these lesions is unknown, but the increasing incidence and severity of the disease with age, in the absence of signs of inflammation, support a degenerative process called endotheliosis.
If in a broad sense these changes in the valves can be considered a rheumatoid disease, then etiologically they cannot be compared with human rheumatoid endocarditis, since the effect of bacterial pathogens has not been proven. Mitral valve insufficiency, which is based on true bacterial endocarditis, is very rare in dogs. In such cases, simultaneous damage to the aortic valves occurs.
Valve leaflet lesions begin with fragmentation of elastic fibers and fibroplasia. The deposition of mucopolysaccharides in the subendothelial and fibroelastic layers increases. On the free edges of the valves, solid nodular thickenings are formed, which determine the contracture of the valves with the impossibility of complete closure. As a result of these changes, there is a reverse flow of blood into the atria.
The intensification of the reverse blood flow leads to overstretching of the walls of the atria, which further increases the divergence of the valves. From the crowded atria during diastole, an increased amount of blood enters the ventricles of the heart, which creates an increased load and causes hypertrophy, and subsequently expansion of the ventricles. The entire structural complex of atrioventricular valves is involved in the process, microscopic intramural myocardial infarctions of the left ventricle develop. As an outcome, extrasystole or paroxysmal tachycardia may occur.

breed predisposition.
AV valve insufficiency can be found in any dog, but occurs predominantly in small to medium breed dogs.

Floor. Males get sick more often and more severely than females.

The disease is manifested by mitral valve insufficiency in 75% of cases, less often by a combination of mitral and tricuspid valve insufficiency and only sometimes by one tricuspid valve insufficiency.
Isolated mitral lesion is especially common in male Cocker Spaniels, and tricuspid valve lesion in dachshunds.

Clinical signs.
The picture of the disease in atrioventricular valve insufficiency some time after the asymptomatic period is quite characteristic. Decompensation of mitral valve insufficiency occurs with the appearance of signs of blood stagnation in the pulmonary circulation.
A chronic cough develops, sometimes with shortness of breath and cyanosis, worse at night or when the animal is excited. The animal stands with its head held high and elbows wide apart. During coughing fits, the dog expectorates a little white or slightly blood-colored foam, which is immediately swallowed. New bouts of coughing can provoke squeezing of the trachea with a collar or palpation of the organ. With decompensated tricuspid valve insufficiency, signs appear that indicate blood stagnation in the systemic circulation. Note peripheral edema, expansion of peripheral veins, enlargement of the liver and spleen, ascites (Fig. 30), hydrothorax, cardiac cachexia. The addition of arrhythmia is indicated by cases of loss of consciousness by animals. Then a non-rhythmic, accelerated pulse with an increased push or a pulse deficit is determined.

Susceptibility: Dogs, Cats

Clinic:
Auscultation
This pathological condition in dogs produces a familiar sound with variable intensity, characterized by the following:
Localization in space: 5-7 intercostal space, parasternally on the left ...
Localization in time: mostly protosystolic, but sometimes holosystolic
Its soft regular specific "outboard engine" type sound
In fact, these characteristics must be taken seriously with some caution, because objects have many variations:
· Since the intensity is very significant (5/6 - 6/6) the auscultatory field is very extensive on the left and right even to the caudal lobes of the lungs, thus making the main localization very delicate.
Since valvular fibrosis is accompanied by parietal hyperkinesia, prolapse or rupture of the cord, the tone of the noise can be completely different: musical, such as dry friction, rough sounds, any outside the norm.

General clinic:
1. Abdominal distension;
2. Abnormal behavior, aggression, change in habits;
3. Anorexia (lack of appetite, refusal to eat);
4. Arrhythmia, irregular heart sounds;
5. Ascites, accumulation of fluid in the abdominal cavity;
6. Auscultation: Abnormal lung or pleural sounds, rales: wet and dry, whistles; 7. Fast fatigue during physical. load;
8. galloping rhythm;
9. Hepatosplenomegaly, splenomegaly, hepatomegaly;
10. Dyspnoe (difficulty breathing, shortness of breath);
11. Distension of peripheral veins, jugular distension;
12. Intra-abdominal masses;
13. Cough;
14. Congestion of the oral mucosa, erythema, redness, hyperemia;
15. Fainting, syncope, convulsions, collapse;
16. Propulsion, inability to rise;
17. Pulse deficit, absence of pulse;
18. Vomiting, regurgitation, emesis;
19. Heart murmurs;
20. Mucous membranes - cyanosis;
21. Tachycardia, increased heart rate;
22. Tachypnoe, Increased respiratory rate, polyp, hyperpnea;
23. Oppression (depression, lethargy);
24. Perceptible precordial flicker;
25. ECG: Atrial fibrillation (atrial fibrillation);
26. ECG: Atrial expansion (atrial expansion);
27. ECG: Atrial (atrial) premature (premature) tone;
28. ECG: Wandering pacemaker;
29. ECG: Ventricular (ventricular) tachycardia, multifocal or monofocal;
30. ECG: Ventricular (ventricular) premature (premature) tone, multifocal or monofocal;
31. ECG: Absence of "p" wave;
32. ECG: Sinus Arrhythmia;
33. ECG: Sinus tachycardia;
34. ECG: Third degree, complete atrioventricular block;
35. ECG: Enlargement of the ventricles (ventricular expansion), left, right or bilateral;

The diagnosis is made on the basis of auscultation and radiography. Above the fields of the atriventricular valves, a uniform systolic high- or mid-frequency noise of the fourth or fifth degree of intensity is heard.
If pulmonary edema occurs, crepitating moist rales are auscultated throughout the field, as well as the accent of the second heart sound (hypertension in the pulmonary artery). An additional symptom indicating tricuspid valve insufficiency is pulsation of the jugular veins.

X-ray.
On lateral radiographs, the silhouette of the heart appears enlarged and rounded due to the expansion of the ventricles. The heart, as it were, lies with a wide base on the sternum. An increase in the left atrium is evidenced by a bronchial symptom (U-shaped silhouette) formed by the main bronchus, elevated dorsally by this atrium, and a change in the angle of the trachea relative to the thoracic spine. The left atrium looks like a wedge where the overflowing pulmonary veins empty into it.
With an enlarged right atrium, the silhouette of the trachea is pushed a little anteriorly. The caudal vena cava is denser and wider than normal. In the dorsoventral projection, the hypertrophied atria are visible at the base of the heart in the form of separate shadows and are displaced: the left one is from the 2 o'clock position to the 4 o'clock position; right - from "II hours" to "9".

TREATMENT
First of all, it is recommended to reduce the weight of the animal and limit the load. In the case of a compensated defect of the atrioventricular valves, light loads are acceptable; in case of decompensation, their complete restriction is necessary.
Dietary recommendations are also of some importance: a salt-free diet, feeding the animal only once a day in the morning and a sufficient amount of masa, which, with a good appetite of the animal, completely covers its need for potassium.
Potassium supplements are given to dogs with anarexia.
With cachexia, it is recommended to increase the caloric content of the diet due to carbohydrates and fats.
Digoxin is prescribed for life at a dose of 0.022 mg/kg, minus the weight associated with ascites and obesity. The dose of the drug is divided into two doses. The effect is expected in 5-7 days. The appointment of digoxin is limited in case of kidney failure. In this case, digitoxin is more acceptable.
The second important component of therapy is the vasodilator prazosin. It reduces the resistance of peripheral vessels, as a result, the venous blood flow to the heart decreases and the work of the heart is facilitated. It is administered orally at a dose of 0.1-0.5 mg 2-3 times a day, but always against the background of digitalis therapy.
In the presence of congestion in the lungs and the systemic circulation, eufillin (which helps to remove sodium from the body) and furosemide are additionally prescribed.
In case of pulmonary edema, all appointments are performed intravenously, if possible, inhalation with oxygen and alcohol vapor is carried out, bloodletting and anesthesia are performed.
With hydrothorax and ascites in a hospital, thoracocentesis or laparocentesis is performed with the removal of fluid from the cavities.
The fight against arrhythmia is necessary already at later stages. As an antiarrhythmic agent, quinidine sulfate is administered orally at a dose of 11 mg/kg every 6 hours until the arrhythmia attacks are permanently eliminated. In case of remission, the next examination of the animal is done after 4-6 months.

FORECAST
From the moment the disease is discovered, lifelong therapy is necessary. Upon termination of treatment, decompensation phenomena quickly recur. If ascites, hydrothorax, cardiac cachexia occur, the prognosis is unfavorable.

Valvular heart disease is the most common heart disease in dogs.

For unknown reasons, the cusps of the valves located between the atria (upper chambers of the heart) and the ventricles (lower chambers of the heart) begin to thicken and deform; as a result, the valve leaflets are not able to fully close during the closing period of the valves. This defect promotes backflow of blood into one or both atria during ventricular contraction. As the valve defect increases, so does the reverse flow of blood. In some cases, there is a rupture of one of the tendon strings that support the leaflets of the heart valve, which makes it even more difficult for the valve to work.

Diagnostics
In the early stages of heart valve disease, there are usually no clinical signs. The disease is usually detected during a routine examination, when the veterinarian hears a heart murmur. The most common mitral valve is located between the left atrium and the left ventricle. The tricuspid valve, located between the right atrium and the right ventricle, is affected in approximately one third of cases.

Treatment
Chronic heart valve disease is an important cause of heart failure, when the heart is unable to cope with its workload. It is not clear that treating heart valve disease in the earliest stages of the disease will increase a dog's lifespan.

This disease is an infection of the heart valves and the membrane that lines the myocardium (heart muscle). Bacteria enter the bloodstream through wounds or other sources of infection in the body. With the defeat of the heart valves, a pathological proliferation of their tissues in the form of cauliflower, which is called vegetation, is observed. Some of these formations break off and spread through the circulatory system, infecting other organs and tissues. Gum disease is one possible source of bacteria. Dogs treated with drugs that suppress the activity of the immune system (eg, corticosteroids) are susceptible to bacterial infection.

Since the infection can spread to other organs and tissues, dogs with bacterial endocarditis may develop the following clinical signs: apathy, loss of appetite, fever, fever, lameness, changes in behavior.

Diagnostics
Diagnosis is based on cardiac auscultation (the affected dog usually has a heart murmur that varies in intensity from day to day), chest x-ray, and electrocardiological and echocardiographic examinations. Bacteria are identified by blood cultures on a culture of bacteria, and antibiotics most effective against these bacteria are determined by sensitivity testing.

Treatment
Treatment is with antibiotics selected according to the results of bacterial culture testing, which are administered intravenously for the first week, after which they are used orally for a long period of time. Affected dogs are monitored closely with regular monitoring of vegetation size using radiographs and echocardiograms. The prognosis is cautious, since congestive heart failure can develop at any time.

CHF - cardiovascular failure, CHF - congestive heart failure, ECG - electrocardiographic study, ECHO - echocardiographic study, ACE inhibitors - angiotensin-converting enzyme inhibitors, SNK - capillary filling rate

In this article, we will continue the consideration of heart diseases, the most common in the practice of a veterinarian.

One of the most common cardiac pathologies in older dogs is endocardiosis of the atrioventricular valves, in particular the mitral valve. The frequency of occurrence of this disease depends on the ratio of representatives of different breeds in a particular region and averages 70% of heart pathologies in dogs.

Endocardiosis - myxomatous degeneration of atrioventricular valves of a non-inflammatory nature. This condition is also known as mucoid, myxomatous valvular degeneration, or chronic valvular fibrosis. The disease is characterized by the accumulation of glucosaminoglycans and fibrosis of the leaflets and tendon strings.

According to autopsy studies of Buchanon, Buchanan, (1979), valve pathology has the following distribution: 62% endocardiosis of the mitral valve only; 1% only tricuspid; 33% - both.

Predisposition:

The highest predisposition and early onset of the disease was noted in Cavalier King Charles Spaniel dogs. Polygenic inheritance is assumed with the influence of sex and age. Representatives of such breeds also belong to the risk group: Toy and Miniature Poodle, Miniature Schnauzer, Chihuahua, Pomeranian, Fox Terrier, Cocker Spaniel, Pekingese, Boston Terrier, Miniature Pinscher, Whippet. Of the larger breeds, endocardiosis can occur in Dalmatians, German Shepherds, and Ridgebacks.

Pathophysiology:

The development of this disease includes the progression of two pathological processes: valve degeneration and mitral regurgitation.

Valvular degeneration. The primary defect is abnormal valve contractions, which lead to leaflet prolapse, which in turn increases pressure on the leaflets directly (improper leaflet closure) and indirectly (increased regurgitant flow). Regurgitation and pressure on the valve causes endothelial dysfunction and activates fibroblast growth, leading to subendothelial glycosaminoglycan deposition and fibrosis. In the future, these processes entail violations of the valve structure and an increase in regurgitation, and increased pressure due to prolapse and changes in the structure of the valves lead to rupture of the tendon strings (chords), aggravating the degree of regurgitation. In the final stage, the valve is a thin, fibrous and narrowed leaflets, mainly with signs of rupture of the tendon strings.

Mitral regurgitation and congestive heart failure. Valve damage progresses, causing insufficient closure of the leaflets, leading to regurgitation, the severity and development of which directly depends on the degree and speed of heart valve damage. As a result of compensatory mechanisms, there is an expansion of the atrium and ventricle, eccentric hypertrophy, as well as an increase in strength, frequency of contraction and activation of neurohormonal systems. In turn, ventricular dilatation further increases regurgitation, provoking secondary valvular insufficiency.

As the disease progresses, compensation for regurgitation is no longer possible, resulting in a decrease in cardiac output and an increase in venous pressure, followed by pulmonary edema (left-sided CHF) or ascites (right-sided CHF). Pulmonary hypertension may develop as a consequence of left-sided heart failure.

Symptoms:

With the development of endocardiosis, the most common symptoms are coughing (sometimes the dog coughs up a little white foam, which it swallows back), shortness of breath, exercise intolerance, the animal may become restless at night due to difficulty breathing when lying down. There may be syncope due to physical activity or excitement, as well as when coughing (cough syncope) or associated with supraventricular tachyarrhythmia.

Coughing fits become more frequent, especially after drinking or exercise. Persistent diffuse pulmonary edema develops, giving crepitus or moist rales on auscultation. Gradually, not only the left, but also the right side of the heart is affected, which leads to the expansion of peripheral veins, liver enlargement, and ascites. Atrial stretch and myocardial degeneration is often the cause of premature atrial contraction or paroxysmal tachycardia.

It should be noted that this disease can be asymptomatic for several years.

Clinical examination:

Auscultation of a dog without clinical symptoms reveals:

– Systolic click (early stage): high-pitched, sharp sound between S1 and S2 heart sounds. This sound is often mistaken for an additional heart sound (causing the occurrence of a gallop rhythm).

– Apical systolic murmur of the mitral or tricuspid valve.

– Mild, early or late cholosystolic murmur (grades 1-2/6) corresponding to moderate to severe regurgitation.

Examination of a dog with CHF reveals:

– Loud heart murmur (level 4-6/6).

– Weakening of the 1st tone.

- Most often, supraventricular arrhythmias are detected. Atrial fibrillation indicates a severe form of the disease with a poor prognosis.

– Weak pulse on the femoral artery and pulse deficit.

– Increased CNS and mucosal pallor (Fig. 1).

– Tachypnea, respiratory distress and orthopnea.

– Wheezing when breathing, sometimes obvious pulmonary edema.

- Pink foam in the nostrils and nasopharynx in acute, severe pulmonary edema (fulminant CHF).

- Ascites and swelling of the jugular veins (with right-sided heart failure).

Rice. 1. Pale mucous membranes

Electrocardiographic study

In an electrocardiographic study, there are various signs depending on the stage of the disease. An increase in the left atrium is characterized by dilated and bifurcated P waves (P-mitrale) (Fig. 2, 3). An increase in the left ventricle can be manifested by an increase in the voltage of the R wave in the 2nd lead, a left-sided displacement of the electrical axis of the heart. With the development of dystrophic changes in the myocardium, extended, jagged QRS complexes can be recorded. Unfortunately, ECG is an insensitive method for making a diagnosis, but the most effective test for determining arrhythmias. The presence of tachyarrhythmia, atrial fibrillation, or ventricular depolarization (Fig. 4) on an ECG usually indicates a severe course of the disease.

Rice. 2. P wave expansion

Rice. 3. Expansion and notching of the P wave

Rice. 4. Single left ventricular extrasystole

X-ray examination

In endocardiosis, the size of the heart varies from normal to left-sided or generalized cardiomegaly (Fig. 5, 6). An increase in the left atrium in the lateral projection is indicated by a dorsal displacement of the distal quarter of the trachea and splitting of the main bronchi; dorsoventral projection shows accentuation of the angle between the main bronchi; a double shadow at the six o'clock position, where the caudal margin of the atrium continues outside the left ventricle, and the left atrial appendage protrudes at the one to three o'clock positions. With the development of left-sided heart failure, the pulmonary veins are wider than the accompanying pulmonary artery; Air bronchograms are typical, but not pathognomonic, of cardiogenic pulmonary edema. In general, congestion and edema are perihilar, throughout the lung field, eventually showing changes.

Rice. 5. Lateral projection. Severe cardiomegaly with expansion of the shadow of the heart in the craniocaudal direction and with a displacement of the trachea dorsally

Echocardiographic study:

Two-dimensional echocardiographic scanning reveals eccentric hypertrophy of the left ventricle, dilatation of the left atrium (the degree of dilatation depends on the stage of the disease), significant deformation and thickening of the mitral valve leaflets (with severe disease), rupture of the tendon filaments (rare complication). Significant mitral valve prolapse and an echo from a ruptured tendon filament, rupture of the left atrial wall (a rare complication), a moderate amount of effusion in the pericardial cavity, and a significantly dilated left atrium are determined.

When scanning in the M-mode, eccentric hypertrophy of the left ventricle is noted, an increase in the end-diastolic size without thickening of the posterior wall, hyperkinesia of the interventricular septum with volume overload, the average value of the shortening fraction is 40%, which decreases in the final stage of the disease - myogenic dilatation.

Complications of endocardiosis:

The most severe complications of endocardiosis are left atrial rupture and avulsion of the chord. In particular, atrial rupture can lead to the rapid development of cardiogenic shock with a fatal outcome.

Differential diagnosis:

The list of differential diagnoses includes: congenital mitral valve dysplasia, mitral regurgitation secondary to primary cardiomyopathy (DCM), mitral valve infective endocarditis, and systemic hypertension.

Forecast:

In the SVEP study, conducted on Cavalier King Charles Spaniel dogs that had a heart murmur in the absence of heart enlargement, the median time to onset of symptoms of heart failure was well over 3 years. The article by Borgarelli et al (2008) showed that in a more mixed group of dogs with mitral regurgitation that did not suffer from clinical manifestations of heart disease, less than 50% of such animals died from complications of this disease during the period of dynamic observation.

Treatment:

Asymptomatic stage (modified AHA/ACC stage B)

• Owner education (information about the disease and early symptoms of heart failure)
• Blood pressure measurement
• Plain chest x-ray (/-ECG) and re-examination annually
• Maintain normal body weight/condition
• Regular physical activity of low or moderate intensity
• Avoid intense physical activity
• Avoid salty foods; consider diets with moderate salt restriction
• Administering an ACE inhibitor to asymptomatic patients showing progressive cardiomegaly may slow deterioration, but this hypothesis has not yet been fully proven.

Symptoms of heart failure are mild to moderate (modified AHA/ACC stage C, chronic):

• Furosemide if needed
• Amlodipine
• ACE inhibitors
• Pimobendan (may be used with or without ACE inhibitors)
• /-digoxin (indicated for atrial tachyarrhythmias, including fibrillation)
• /- additional diuretics (spironolactone, hypothiazide)
• Antiarrhythmic therapy if necessary
• Limitation of physical activity
• Home monitoring of respiratory rate (/- heart rate)
• Severe symptoms of acute congestive heart failure
• Oxygen Support
• Furosemide (higher doses, parenteral)
• Amlodipine?
• Vasodilator therapy
• Antiarrhythmic therapy if needed
• /- positive inotropes
• Once the patient is stabilized, oral pimobendan/-digoxin therapy may be used.
• /- bronchodilator
• Thoracocentesis for large pleural effusions

Treatment for chronic relapsing or refractory heart failure (modified AHA/ACC stage D):

• increase dose/frequency of furosemide; if necessary, they can be reduced within a few days after the symptoms subside
• increase dose/frequency of ACE inhibitor (from 1 to 2 times a day)
• increase the dose of the second diuretic
• thoracocentesis or abdominal centesis if necessary
• antiarrhythmics if needed
• sildenafil for secondary pulmonary hypertension (eg 1-2 mg/kg every 12 hours)
• trial treatment with a bronchodilator or antitussive

Patient monitoring:

In asymptomatic dogs, x-rays are taken when the first murmur is detected and then every 6 to 12 months thereafter to check for progressive cardiomegaly.

The frequency of re-examination of animals treated for heart failure depends on the severity of the disease and on the presence of complicating factors.

Patients with newly diagnosed or decompensated congestive heart failure should be evaluated more frequently. After an episode of congestive heart failure, once a week during the first month of treatment; repeat chest x-ray and ECG at first weekly check-up and at subsequent visits if any changes are observed on general physical examination.

Dogs with chronic heart failure whose symptoms are well controlled may be evaluated less frequently, usually several times a year.

Conclusions:

Endocardiosis is the most common heart disease in small breed dogs, indicating the need and importance of routine cardiac evaluation, even in asymptomatic patients. This is especially true for representatives of the Cavalier King Charles Spaniel breed, in which the genetic nature of the disease has been proven. Early contact with a specialist, timely diagnosis and appropriate treatment will slow down the development of the disease and thereby improve the quality of life of the animal.

Mitral valve endocardiosis in dogs What is important for owners to know? The heart of a dog is a symbol of devotion and fidelity for all time. But despite their energy and endurance, our faithful friends, especially with age, begin to suffer from cardiovascular diseases, and this often takes the owners by surprise. In order to see the signs of heart failure in time, you need to know very little and be attentive to any changes in the behavior of the dog. Then, as a result of a timely diagnosis and adequate therapy, your beloved dog will warm your life with its presence for a long time to come.

What is mitral valve endocardiosis?

Mitral valve endocardiosis is also called myxomatous degeneration of the heart valves, the mitral valve, which separates the left atrium and left ventricle, and the tricuspid valve, in the right half of the heart, can be affected. Most often - 60% of cases of damage to the mitral valve, 33% - to the degeneration of both valves, and 6% - only the tricuspid valve.

Mitral valve endocardiosis in dogs is an organic disease; during its course, degenerative changes occur in the structure of the connective tissue that makes up the chords and leaflets of this bicuspid valve. First, small nodules appear, which increase and connect with each other, eventually forming growths and plaques. The tendinous strings or valve chords also become thicker and coarser. The valve itself thickens, deforms, and its flaps cease to close tightly. There is a pathology of the mitral valve, it does not cope well with its function, passing a stream of blood from the ventricle into the atrium (mitral regurgitation). This is how it develops heart failure with all the ensuing consequences.

This disease is one of the most common in dogs, according to statistics, it is diagnosed in 60% of visits to the veterinarian due to cardiovascular ailments.

It must be said that mitral valve endocardiosis in dogs progresses very slowly, as the body uses powerful compensatory mechanisms to ensure the efficient functioning of the heart and blood vessels.

It is believed that the disease does not debut until the age of five, but usually the owners go to the doctor when the disease is already causing visible changes in the health of the four-legged. The older the dog, the more often endocardiosis is found in it.

Dogs of dwarf and medium breeds are susceptible to this disease: dachshunds, dwarf poodles, Pomeranian, Chihuahua, Cavalier King Charles Spaniels. Of the large breeds - German Shepherds.

Mitral valve endocardiosis in dogs: symptoms

A disease such as mitral valve endocardiosis in dogs develops over the years, at first it does not declare itself. Only during preventive or scheduled examinations, for example, before vaccination, the doctor may hear a heart murmur.

The dog's appetite usually does not suffer and remains good despite the illness.

Complications of mitral valve endocardiosis in dogs

With further progression of chronic heart failure stagnation in the lungs, intestines, internal organs increases, which weakens their functioning. Under conditions of blood stagnation, bacteria that inhabit the mucous membranes are activated, thereby provoking the development of inflammatory processes in the lungs, bronchitis, gastroenterocolitis. It is not uncommon for affected dogs to have pulmonary arterial hypertension. Death occurs either due to increase in chronic heart failure, or due to cardiac death syndrome (thromboembolism, atrial rupture, pulmonary edema).

Mitral Valve Endocardiosis in Dogs: Diagnosis

When diagnosing mitral valve endocardiosis in dogs, the doctor will listen to the dog's heart and lungs, identify typical heart murmurs, and prescribe blood tests: general and biochemical. An X-ray examination is mandatory, on which you can see an enlarged shadow from the left atrium and ventricle, upward displacement of the bronchus due to left atrial pressure, pulmonary edema, congestion in the pulmonary veins, and an enlarged liver. Echocardiography can effectively detect a number of pathological changes in the heart.

Mitral valve endocardiosis in dogs: treatment

Unfortunately, cure completely mitral valve endocardiosis in dogs
impossible, the most important thing is to maintain the health of the dog at a sufficient level.

In this case therapy is to reduce stagnation in the large and small circles of blood circulation, improve heart function, minimize stress on the heart muscle. For this purpose, drugs such as ACE inhibitors, diuretics, cardiotonic drugs, agents that reduce platelet aggregation, corticosteroids prescribed by a doctor, and metabolic drugs are used.

The drugs are taken constantly, as the disease is chronic and gradually progresses. It is also necessary to ensure that when giving drugs, signs of intoxication do not increase. Then the drugs should be canceled and, under the supervision of a doctor, other drugs should be selected that are safer for this particular dog.

Mitral Valve Endocardiosis in Dogs: Conclusion

Mitral valve endocardiosis is a common pathology among older dogs, especially small and medium breeds. The attentive attitude of the owners, the timely detection of the disease make it possible to select the optimal therapy regimens and improve the patient's quality of life and its duration.

As you can see, the care of the health of the pet rests entirely on the shoulders of the owner, this is especially true when the age of the dog has exceeded the average. It is extremely important to undergo routine preventive examinations in order to diagnose heart disease at an earlier stage, thereby prolonging the life of a pet.

Our veterinary emergency center "Ya-VET" employs specialists of a narrow profile, including veterinary cardiologist. Such a doctor specializes in diseases of the cardiovascular system and will select the appropriate diagnostic examinations for the dog in order to differentiate endocardiosis from other pathologies: cardiomyopathy, pneumonia, pulmonary embolism, congenital heart disease. The center has all the necessary modern equipment for such examinations: ultrasound, X-ray, ECG.

If you notice alarming symptoms, do not miss the time, call our veterinary center and get a free consultation from an experienced veterinarian. He will give advice on providing first aid to the pet before the doctor arrives, because it is much easier and faster to call a doctor at home without wasting time in traffic jams and queues at the clinic. In addition, a sick pet is more difficult to endure stress and emotional stress, he easily gets tired of a lot of strangers and animals. If necessary, the animal will be taken to the hospital for emergency care and medical supervision.

The experience and professionalism of our specialists, love for animals allow us to say with confidence: your pets will be in good hands and will receive the most necessary assistance in full. And this means that soon a healthy dog ​​will again enjoy life with you in the family circle!