Myxomatous degeneration of the mitral valve leaflets. Why does myxomatous degeneration of the mitral valve leaflets appear and what threatens? What changes does the pathological process imply

The quality of human life, his health largely depends on the state of the cardiovascular system. The heart and blood vessels perform important functions - they pump blood, which supplies all organs and tissues with oxygen and nutrients, removes carbon dioxide. The modern level of medical technologies, innovations in treatment and diagnostics have significantly reduced mortality from cardiovascular diseases, but they still remain the main causes of death in all countries. One of the serious pathologies diagnosed by cardiologists in people of middle and old age is myxomatous degeneration of the mitral valve.

What changes does the pathological process imply?

This pathological condition of the human heart has other names. Doctors can give a diagnosis to a patient using the terms “mitral valve prolapse” or “endocardiosis”.

The mitral valve separates the left atrium from the left ventricle. Under normal conditions, it does not allow the reverse flow of blood from the atrium to the ventricle of the heart. For some reason, most often due to a genetic predisposition or infections of a viral nature, a person experiences degeneration of the valve leaflets - their stretching and thickening.

This process is called MVP (mitral valve prolapse), its development in a patient causes disturbances in the work of the heart. There is a reverse reflux of part of the blood from the atrium into the ventricle - this phenomenon is called regurgitation. The development of the disease leads to a change in the patient's condition, the appearance of noise during the work of the heart.

The myxomatous process leads to further changes in the functioning of the organ. Its result is an enlarged size of the left ventricle, and subsequently the whole heart, arrhythmia, heart failure, disturbances in the work of other valves.

What do degenerative changes in organ tissues look like?

Changes depending on the degree of the disease

Myxomatosis of the mitral valve goes through three stages of development (degrees). Each of them has its own characteristics, requires a different approach to therapy.

Myxomatous degeneration of the valve of the first degree is expressed in a slight thickening of its valves - less than 5 millimeters. At the same time, the valves close completely, there are no manifestations of the disease at all. In this condition, observation by a cardiologist and a change in the habitual lifestyle with a revision of attitudes towards bad habits, nutrition, physical activity are required.

The second stage of the disease is diagnosed when the valve thickens in the range from 5 to 8 millimeters, while stretching of its valves, a violation of their closure, and a change in the shape of the hole between them are observed.

Thickening of the valve leaflets more than 8 millimeters indicates the third stage of the disease. With it, the valve leaflets do not close, there is a pronounced deformation of the mitral ring.

Manifestation of disease symptoms

Any suspicion of heart disease should be the reason for an urgent appeal to a cardiologist. Myxomatous degeneration of the mitral valve leaflets manifests itself depending on the degree of progression of the pathology. Its first degree develops asymptomatically, the subsequent stages of the disease are manifested by characteristic symptoms:

• the working capacity of a person, his endurance decreases, steady fatigue appears;
• there is pain in the chest;
• cardiac arrhythmia appears - the heartbeat can increase without physical exertion, there are noticeable interruptions in the work of the heart;
• possible fainting, dizziness, nausea;
• there is a feeling of lack of air, accompanied by shortness of breath and cough.

Ways to confirm the diagnosis and conduct an examination

The diagnosis of "myxomatous degeneration" can be established using several types of diagnostics. During the initial examination of the patient, the doctor may suspect the presence of the disease when listening to the heart tone with a stethoscope. Systolic murmur becomes an important reason for referring the patient for a detailed examination. It is carried out using:

• ultrasound examination;
• radiography chest;
• interpretation of the data obtained during the removal of the electrocardiogram;
• laboratory analyses.

Such diagnostic methods make it possible to study the changes that have occurred in the valve, identify possible threats to the further development of the pathology, and prescribe treatment.

Treatment and preventive actions

The patient's condition at initial stage the development of the disease does not require the use drug treatment. It is prescribed by a cardiologist if the pathology begins to progress.

Drug therapy in this case is aimed at achieving the following results:

• restoration of cardiac activity;
• removal of pain symptoms;
• prevention of blood clots.

Such treatment is indicated for the second degree of the disease. The subsequent, third degree involves surgical intervention. Its goal is to replace the mitral valve with a prosthesis. During the intervention, high-tech techniques are used that have a sparing effect on the health of the operated person.

During and after treatment, it is important to observe preventive measures. A patient with myxomatous degeneration of the mitral valve requires:

• forget about drinking alcohol, smoking;
• use physical activity - its types and intensity must be agreed upon by the doctor;
• switch to a diet with useful products prepared in a certain way.

It should be remembered that the symptoms of a myxomatous condition of the mitral valve require mandatory medical attention. Joint actions of the doctor and the patient will help improve the patient's condition, avoid serious complications of the pathology.

More:

Is it possible to play sports with mitral valve prolapse of the 1st degree? What are the restrictions? Degrees of mitral valve insufficiency, characteristics of the disease and treatment

Myxomatous degeneration of the mitral valve is not such a serious pathology as it might seem at first glance. It has several alternative names that a person can hear from a cardiologist after undergoing an examination: endocardiosis, valve prolapse.

To be able to learn more about such a defect as myxomatous degeneration of the mitral valve leaflets, what it is and how to deal with it, we will consider further. We are talking about thickening and stretching of the valve leaflets, contributing to their loose closure. As a result, the formation of reverse blood flow directed towards the ventricles.

There are several degrees of pathology, depending on which the prognosis for a person changes, a decision will be made about the appointment of an effective treatment:

• Grade 1 - here there is a thickening of the valve leaflets up to 3-5 mm. Such changes do not violate their closure, therefore, the symptoms of pathology in humans are usually absent. Doctors do not sound the alarm when diagnosing this stage of the disease, they recommend reconsidering the lifestyle, conducting preventive examinations twice a year;
• Grade 2 - the valves are stretched, more thickened, their performance reaches 5-8 mm. In addition, there is a deformation of the contour of the mitral orifice. Stretching and single ruptures of chords are diagnosed. The closure of the valves is broken;
• Grade 3 - thickening of the mitral cusps is noticeable very well, their thickness exceeds 8 mm. There is a deformation of the mitral ring, stretching and rupture of the chords. The closure of the valves is completely absent.

Conclusion: the 1st stage of the pathology is considered safe, there are no disturbances in the work of the heart, there is no regurgitation (reverse blood flow). At stages 2 and 3, the blood in a certain volume returns back, because the closure of the valves is impaired or completely absent. This state of affairs should not be ignored, because there is a high risk of developing serious complications.

Important! In order for the left ventricle to cope with the volume of blood that has increased due to the reverse flow, it will begin to increase in size. The result is LV hypertrophy. But, this is only one of the negative consequences of the vice we are considering.

It is known that myxomatous degeneration of the mitral valve leaflets only progresses with age. There is a risk of additional complications: UA deficiency, bacterial endocarditis, stroke, sudden death. The prognosis is not encouraging, so you should take care of the possibility of timely detection of this pathology, which allows you to take effective measures for its treatment and prevention of complications as soon as possible.

Signs of MD

At the initial stage, any signs will be absent, because, as in this case, the blood circulation is not disturbed, regurgitation is completely absent. But, with the transition of the disease to a more serious stage, a person will feel the following symptoms:

1. decreased performance, general weakness, fast fatiguability even with minimal loads;
2. shortness of breath that appears with minimal physical or emotional stress, a feeling of lack of air;
3. pain in the heart, which most often manifests itself in the form of tingling. Occur periodically, have a short duration;
4. dizziness, accompanied by arrhythmia, often leading a person to a pre-fainting state;
5. cough, it should be considered as an additional symptom that may not appear. At first it is dry, then it is accompanied by sputum, which may contain streaks of blood.

When visiting a doctor, signs of a malfunction of the cardiac system will first of all be noticed when listening to the heart. The doctor will hear the noises that accompany the backflow of blood to the ventricle. This can already become the reason for a more detailed examination, including the collection of anamnesis, laboratory tests, electrocardiography, echocardiography.

If electrocardiography shows only the presence of a violation, its stage, then ultrasound of the heart will be able to provide more complete information, because it will allow you to determine the size of the valves, the features of their deformation, in other words, all the pathological changes that take place in this case.

How to treat MD

At the initial stage of the development of the disease, there will be no treatment, because there will be no urgent need for it. The patient will be recommended only a systematic visit to a cardiologist in order to determine the intensity of the progression of the condition, control the pathology.

If myxomatous degeneration of the mitral valve leaflets begins to worsen, a person will be prescribed a number of medications that will help fight symptoms and slow down the development of the disease. These are drugs that remove excess fluid from the body, thus removing excess stress from the heart; medicines that restore heart rate, eliminate arrhythmia, other medicines that will be relevant in this case.

Prevention of MD

When it comes to a serious disease or pathology that poses a high danger to human health and life, the issue of prevention always becomes relevant. In order to choose these measures, you need to find out about the reasons that provoke a particular ailment. In the case of MD, the exact causes of its occurrence are not yet known. Doctors suggest that it develops due to a genetic predisposition, but this statement has not been proven.

Accordingly, it is difficult to talk about preventive measures in this case. The only thing that will help maintain the health of the heart and prolong its work for many years is a healthy lifestyle, on this the state of health of the body of each of us depends on 80%, including the work of its main motor - the heart. Therefore, it is better to give up bad habits, start eating well and resting properly, exercising physical culture but without being too zealous.

In contact with

Many cardiovascular diseases debut in adulthood, or are detected by chance during preventive examinations.

Myxomatous degeneration of the mitral valve is one example of such scenarios.

Pathology requires dynamic control and conservative therapy to prevent complications.

Myxomatosis of the mitral valve is a disease based on an increase in the volume of its valves due to the spongy layer located between the ventricular and atrial valve surfaces. This process occurs due to a change chemical composition cells when the content of mucopolysaccharides in them increases significantly.

The outcome of all such deviations is valve prolapse, gradually leading to a number of pathological processes:

• the phenomena of fibrosis on the surface of the valves;
• thinning and lengthening of tendon chords;
• damage to the left ventricle, its dystrophy.

The changes are irreversible, causing aggressive tactics of patient management.

Distinctive properties of pathology are:

1. It affects people over 40 years of age.
2. More often diagnosed in men.
3. The presence of mitral regurgitation (reverse blood flow when the heart muscle relaxes after contraction).
4. Progressive course of the disease.
5. Formation of heart failure.

The severity of the disease is determined by the degree of prolapse (sagging) of one or two valves into the cavity of the left ventricle. The severity of myxomatous degeneration is determined by ultrasound of the heart.

The reasons for the development of myxomatous degeneration of the mitral valve leaflets are not known very much. The most common:

• rheumatism;
• chronic rheumatic heart disease;
• secondary atrial septal defect;
• congenital defects;
• hypertrophic cardiomyopathy;
• cardiac ischemia.

Pathology always develops secondarily. An important role is played by hereditary predisposition to the occurrence of myxomatous degeneration.

0 Signs of myxomatous degeneration are absent on ultrasound scan, but initial changes can be detected by examining histological materials

I Unexpressed thickening of the valves - no more than 0.03–0.05 cm; mitral valve opening becomes arched

II A pronounced increase in the valves up to 0.08 cm with a violation of their full closure, involvement of chords in the process

In the early stages of the development of pathological changes, the patient does not complain, or they are due to the main problem. As you progress, you will notice:

• increased fatigue;
• heartbeat;
• sharp fluctuations in blood pressure;
• anxiety;
• panic attacks;
• pain in the apex of the heart, not associated with physical activity;
• increased shortness of breath;
• decreased resistance to physical and everyday stress;
• heart rhythm disturbances;
• the appearance of edema in the lower 1/3 of the lower leg and feet.

The severity of symptoms increases as the degree of leaflet prolapse increases.

Myxomatosis of the mitral valve is determined by the results of several studies:

• assessment of patient complaints;
• history data;
• objective examination;
• additional examination methods.

During the examination, the characteristic auscultatory signs of pathology are:

• systolic click;
• midsystolic murmur;
• holosystolic murmur.

A distinctive feature of the auscultatory picture in myxomatous degeneration is its variability (the ability to change from visit to visit).

From an additional examination, the doctor appoints:

• Holter monitoring;
• Ultrasound of the heart (transthoracic, transesophageal) is the only method that allows you to visualize pathological changes;
• tests with dosed physical activity;
• radiography of the lungs;
• MSCT;
• electrophysiological study.

Such extensive diagnostics is needed to determine further tactics for managing the patient and monitoring ongoing therapy.

Myxomatous degeneration of the cusps of the mitral valve of 0-I degree does not require aggressive measures. Doctors at the same time choose expectant tactics, regularly assessing the patient's condition. No specific treatment is carried out. The patient is given a number of general recommendations:

• exclude heavy physical exertion;
• normalization of body weight;
• therapy of concomitant diseases;
• healthy sleep;
• physiotherapy;
• proper nutrition.

Patients with a higher degree are shown symptomatic treatment:

• β-blockers;
• calcium antagonists;
• ACE inhibitors;
• antiarrhythmic drugs.

Of great importance is the impact on the mental status of the patient. For these purposes, magnesium preparations, sedative drugs are used.

Surgical correction is carried out with a pronounced clinic, an increase in the degree of myxomatosis.

The tactics of patient management is determined by the cardiologist individually.

3 Pathogenesis of the development of the disease

Thickening of the mitral valve leaflets

Stretching and thickening of the mitral valve cusps causes a violation of the closure of the latter, which contributes (due to higher pressure in the left ventricle than in the left atrium) backflow of blood into the cavity of the left atrium. This, in turn, causes hyperfunction with subsequent hypertrophy of the left atrium and relative insufficiency of the valves of the pulmonary veins, and subsequently hypertension in the pulmonary circulation, which causes most of the symptoms of this disease.

I degree - the cusps are thickened up to 3-5 millimeters, while the closure of the valve is not disturbed, therefore the patient has no clinical manifestations, because of this, it is possible to identify the disease at this stage only when examining diseases of other systems or during preventive examinations.

No special treatment for myxomatosis of the mitral valve of the 1st degree is required, even restrictions on physical activity are not given, the main thing is to lead a healthy lifestyle, try not to get sick with various viral and streptococcal infections and periodically conduct preventive examinations (most often recommended 2 times a year).

Degenerative mitral valve disease

II degree - the thickening of the valves reaches 5-8 millimeters, the closure of the valve is broken, there is a reverse reflux of blood. Also, the examination revealed single detachments of the chord and deformation of the contour of the mitral valve. At this stage, the doctor describes the lifestyle, nutrition and frequency of preventive examinations.

III degree - the thickening of the valves exceeds 8 millimeters, the valve does not close, there are complete detachments of the chord. At the same time, the patient's condition deteriorates sharply, symptoms of acute left ventricular failure appear, so emergency specialized treatment of this patient is needed, and at this stage it is very important to seek medical help early.

Features and causes of pathology

Myxomatous degeneration of the mitral valve

The exact cause of myxomatous degeneration of the mitral valve is not known, often this pathology is associated with a hereditary predisposition. Most often this disease affects people who have impaired education cartilage tissue, there are congenital defects and diseases of the joints.

Degeneration of the mitral valve (myxomatosis mitral valve) last years scientists associate with hormonal disorders of various origins. There is also a certain relationship between this pathology and various viral diseases, which have a damaging effect on the cusps of the heart, as well as streptococcal infection, which causes direct damage not only to the valvular apparatus, but also to the endocardium of the heart.

Diseases of the cardiovascular system

Myxomatosis mitral valve refers to a common heart disease that is diagnosed in people of various age category. IN modern medicine several names for this pathology are used, and most often specialists use terms such as valve prolapse and degeneration.

Prolapse is a bulging or bending of the cusps of the heart valve in the direction of the proximal chamber of the organ. In the event that we are talking about mitral valve prolapse, then such a pathology is accompanied by bulging of the leaflets towards the left atrium.

P rolapse is one of the most common pathologies that can be detected in patients of absolutely any age.

Myxomatosis of the mitral valve can develop for various reasons, and experts distinguish between primary and secondary prolapse:

1. Primary valve prolapse refers to a pathology, the development of which is in no way associated with any known pathology or malformations.
2. secondary prolapse progresses against the background of many diseases and pathological changes

Experts say that the development of both primary and secondary prolapse can occur during adolescence.

More information about mitral valve prolapse can be found in the video.

The development of secondary mitral valve prolapse usually occurs as a result of the progression of inflammatory or coronary diseases in the patient's body, resulting in dysfunction of the valves and papillary muscles. If there are systemic lesions connective tissue, then valve prolapse becomes one of characteristic symptoms such a violation.

CARDIOLOGY

UDC 619: 616.12

Myxomatous mitral valve degeneration in Yorkshire Terriers

VC. Illarionov ( [email protected])

Veterinary clinic "Biocontrol" (Moscow).

The article deals with the most common heart pathology in Yorkshire terriers as representatives of small breed dogs - myxomatous degeneration of the atrioventricular valves, or endocardiosis. The pathophysiological mechanism of the development of heart failure in this pathology is described, the main diagnostic criteria are listed, and approaches to the treatment of dogs with various stages of heart failure are determined.

Keywords: myxomatous valve degeneration, heart failure, endocardiosis, echocardiography

Abbreviations: Ao - aorta, IV - intravenous, IM - intramuscular, ACE inhibitors - angiotensin-converting factor inhibitors, EDV - end-diastolic volume index, ESR - end-systolic size, LA - pulmonary artery, PH - pulmonary hypertension , LV - left ventricle, LA - left atrium, MK - mitral valve, MR - mitral regurgitation, MRP - intercostal spaces, MT - body weight, RV - right ventricle, s / c - subcutaneously, RA - right atrium, PPT - area body surface, TSC - tricuspid valve, EF - ejection fraction, FU - shortening fraction, ACVIM - American College of Veterinary Internal Medicine (American College of Veterinary Internal Medicine)

The Yorkshire Terrier is one of the most popular dog breeds in the world. Here is just one quote from the American Kennel Club magazine dedicated to this breed: "The Yorkshire Terrier is a truly phenomenal dog, a small miracle of animal science." Modern Yorkshire Terriers do have a very attractive appearance: small size, beautiful and easy-to-groom coat, round head, short muzzle and large eyes - a classic set of key stimuli of parental feeling. This is one of the young breeds of dogs, bred as a result of crossing various English terriers. In 1874 the breed was registered by the British Kennel Club and entered in the stud book. Yorkies of that time had a rather long body and a larger size, the usual weight for them was 6.. .7 kg. The body weight of modern Yorkshire Terriers ranges from 1.5 to 3 kg. The rapid artificial decrease in body weight and shortening of the body affected not only the exterior, but also the interior - the internal structure of the dog. At the same time, along with the characteristics of the breed, characteristic pathologies were also genetically fixed.

The indisputable advantages of Yorkshire terriers are friendly disposition, courage, devotion, as well as ease of maintenance. People are ready to acquire a companion, a playmate, in other words, joy, but often in addition they receive a bunch of diseases. For veterinarians, Yorkshire Terriers have become one of the integral parts of medical practice. In veterinary cardiology, one of the most common diseases of this breed is chronic illness atrioventricular valves, which develops as a result of a degenerative pathology - myxomatous valve degeneration (another name for the disease is valvular endocardiosis).

Etiology, pathophysiology, clinical signs

Myxomatous valvular degeneration is the result of changes affecting the entire valvular apparatus of the MV or, less commonly, the TCV. Predominantly older dogs of small breeds suffer. The disease is characterized by gradual thickening and deformity of the valve leaflets, starting from the free edges and ending with the involvement of the entire surface of the leaflets and tendon filaments (Fig. 1).

The process of deformation of the valves includes four stages, starting with single thickenings along the edges and ending with confluent changes in the valves and tendon filaments. Lesions result from redistribution of the extracellular matrix, accumulation of glycosaminoglycans, thinning and fragmentation of collagen in the subendocardial layer of the valve leaflets. Similar changes are found in human MV prolapse. Thus, the valve gradually loses its obturator function, and blood begins to be partially thrown into the atria during ventricular systole. The amount of backflow of blood (regurgitation) depends on several factors, but the main ones include the size of the valve defect and the difference between systolic pressure in the ventricles and atria. The atria are chronically overloaded with blood volume and gradually dilate to compensate for the pressure that builds up in them. At the same time, there is a hemodynamic overload of the pulmonary veins and the left ventricle, which in diastole receives an increased blood volume due to regurgitation, which leads to its eccentric hypertrophy. At the same time, antegrade blood ejection into the AO (with UA deficiency) or LA (with TSC deficiency) is reduced due to the preferred route of blood supply to the atria with lower pressure. In order to ensure normal circulation and pumping of additional blood volume, the heart increases stroke volume according to the Frank-Starling law, in which an increase in ventricular EDV causes more stretching of the myofibrils and initiates a stronger contraction. Thus, the myocardium in chronic atrioventricular valve insufficiency is in a state of hypercontractility for a long time. Over time, the compensatory reserves of the body decrease, the pressure in the LA increases (with mitral insufficiency), which causes chronic overload of the pulmonary blood flow with the development of PH

Rice. 1. Macropreparation: thickening and deformation of the MV cusps

Rice. 3. Phonocardiographic image 2. Macropreparation: thrombus from the valve leaflet of the murmur of insufficiency of atrioventricular valves in the mesenteric vessels

and pulmonary edema. LH exacerbates circulatory disorders in the right heart, which provokes congestion in the venous system of the systemic circulation with signs of fluid retention (ascites, hydrothorax, hydropericardium). When the reserve capacity of the heart muscle is exhausted, its systolic function decreases. This causes a drop in cardiac output and the development of general weakness, lethargy and fainting. With pronounced structural changes in the valvular apparatus and LA, complications such as rupture of the tendon filaments or LA, the formation of blood clots on deformed leaflets with the development of thromboembolism of the vessels of the systemic circulation (Fig. 2) can rarely occur.

The disease has a rather long asymptomatic period, which is provided by the body's compensatory reserves, in particular, the activation of the rinin-angiotensin-aldosterone and sympathetic-adrenal systems.

The earliest symptom of pathology is cough, which has a complex pathophysiological mechanism. One of the most significant causes of cough is compression of the left main bronchus by a dilated LA. In this case, mechanical irritation of the cough receptors occurs and the development of a loud barking cough, similar to coughing up a foreign body from respiratory tract. A similar cough develops with tracheal collapse, which is also not uncommon in Yorkshire Terriers. With the progression of heart failure, congestion develops in the vessels of the lungs, which stimulates the juxtapulmonary receptors involved in the formation of the cough reflex. With the development of interstitial and alveolar pulmonary edema, the cough may become softer and more moist.

Tachypnea and shortness of breath, which is expiratory or mixed in nature, occur with the development of interstitial or alveolar pulmonary edema. Such pathological respiratory disorders do not go away even at rest.

Fainting, manifested by a sudden short-term loss of consciousness with a sudden drop in muscle tone, can occur as a result of heart rhythm disturbances, manifest itself with a decrease in cardiac output during sudden physical or emotional

load or be provoked by bouts of coughing with the development of reflex bradycardia.

The most significant sign of the disease in the physical examination of the animal is a pansystolic murmur of mitral or tricuspid regurgitation at the auscultation points of the MV (6th MCI at the level of the costochondral joints on the left) or TSC (5th MCI at the level of the costochondral joints on the right). The murmur has an even configuration and merges with the first and second heart sounds (Fig. 3). The loudness of the murmur correlates with the severity of valvular insufficiency. With volume overload of the left ventricle, an abnormal third heart sound may appear. With the development of PH, the second tone increases due to the pulmonary component. The filling of the pulse remains normal for a long time. With a decrease in systolic function of the myocardium, the pulse becomes empty in filling. With severe heart failure, tachycardia is manifested. On auscultation of the lungs, wheezing is heard in patients with signs of pulmonary edema. However, it is necessary to approach these changes with caution, since wheezing can be symptoms of broncho-pulmonary pathology, which is often found in Yorkshire terriers.

For differential diagnosis, an x-ray examination of the chest is necessary, which allows you to assess the condition of the lungs, respiratory tract, blood vessels and heart. In Yorkshire Terriers, the heart looks large relative to the size of the chest, so for an objective assessment of its silhouette, it is necessary to calculate the cardiovertebral size: the sum of the length of the heart (from the base of the heart under the bifurcation of the trachea to the apex) and the width of the heart (in the widest part, coinciding with the level of the ventral border of the caudal vena cava). The measure of the length of each segment is the thoracic vertebrae, starting from T4. Meaning this indicator in Yorkshire terriers it varies - 9.9 ± 0.6 vertebrae. When evaluating the shape of the heart in the picture in the lateral projection, the phases of respiration and cardiac activity should be taken into account, since the relative size of the heart can be increased with a combination of exhalation and diastole (Fig. 4). The most striking radiographic signs of LA dilatation in the lateral projection are an increase and straightening of the caudodorsal border of the heart with the formation of a right angle pattern, disappearance

Rice. Fig. 4. Scheme of changes in the relative size of the heart on the radiograph in the lateral projection, depending on the phase of respiration

Rice. 5. Scheme of changes in the relative size of the heart on the radiograph in the lateral projection, depending on the phase cardiac cycle

caudal "heart waist", dorsal displacement of the trachea and the left main bronchus (Fig. 5). With an increase in the right parts of the heart, the area of ​​cardiosternal contact expands and the right side of the silhouette of the heart on radiographs in the lateral projection increases disproportionately.

The degree of congestion in the lungs is assessed by the severity of venous congestion: with a significant degree, the diameter of the lobar vein of the cranial lobe of the lung exceeds the diameter of the artery of the same name.

With interstitial pulmonary edema, an X-ray picture of "smoothness" or "turbidity" of the vascular pattern of the lungs occurs, with the situation aggravated and the development of alveolar edema, dense diffuse shading is noted first in the root region, and then in the caudodorsal parts of the lungs (Fig. 6, 7) .

An echocardiographic study reveals signs of an increase in the LA and eccentric LV hypertrophy with MV insufficiency. With TSC insufficiency, an increase in the cavities of the PP and PZh is detected. The severity of changes depends on the stage of the process. The leaflets of the atrioventricular valves are thickened and deformed to varying degrees.

In clinical practice, the most accessible assessment of mitral regurgitation by percentage

decrease in the area of ​​the regurgitation jet to the area of ​​the LA according to the results of color Doppler mapping (Fig. 8): I degree - less than 20%; II - 20...30; III - up to 70, IV degree - 70% or more. The advantages of the method include ease of use and high reproducibility. The disadvantage is that this is a semi-quantitative research method that does not give an idea of ​​the volume of regurgitation.

Assessment of LV myocardial contractility in MR is difficult. Volume overload and the presence of MR lead the myocardium into a state of hyperkinesis. Obtaining normal and subnormal indicators of FU and EF according to the Teybok method indicates a decrease in contractile function. LV CVD is less susceptible various factors. Use the calculation of KSOE:

KSOI = KSR3/PPT

CVID > 30 ml/m2 indicates systolic dysfunction myocardium. Maximum regurgitation rate< 5 м/с говорит о высоком давлении в ЛП или снижении сократимости миокарда.

PH is caused by a persistent increase in pressure in the LA with the development of right ventricular failure. To detect PH, systolic and diastolic pressure in the LA is assessed by the rate of regurgitation on the TSC and the LA valve. In the absence of regurgitation, the mean pressure in the LA is estimated by determining the time of flow acceleration in the LA and the ratio of the flow acceleration time to the total duration of expulsion from the RV. Indirect method - determination of the ratio LA / Ao. Expansion of the pulmonary artery leads to an increase in LA / Ao more than 1.

Electrocardiographic changes reflect hypertrophy of the right and/or left parts of the heart only with pronounced structural changes in the latter. characteristic feature LA hypertrophy in case of MK insufficiency - expansion of the P wave (more than 0.05 s). LV hypertrophy is manifested in an increase in the amplitude of the K wave and the expansion of the OK8 complex (more than 0.06 s) (Fig. 9). Rhythm disturbances are often manifested by supraventricular extrasystoles and rhythms, less common ventricular extrasystoles (Fig. 10), ventricular rhythms and atrial fibrillation. Severe changes in the heart with the development of symptoms of heart failure are accompanied by sinus tachycardia with the disappearance of sinus arrhythmia.

Rice. 6. Chest radiograph in lateral projection.

Signs of chronic MV insufficiency: enlarged LA (arrow) and LV, dorsal displacement of the trachea

Rice. 7. Chest radiograph in lateral projection. Signs of alveolar pulmonary edema: cloudy shading in the region of the roots of the lungs and caudodorsal parts of the lungs

Rice. 8. Echocardiogram (right parasternal access along the short axis at the level of the Ao root) of a patient with chronic UA insufficiency. Significant expansion of the LA cavity

Treatment depending on the stage of the process

The disease develops gradually, which allows you to set the stage of the process. According to the ACVIM classification, the following stages are distinguished: A, B1, B2, C1, C2, D1, D2.

Stage A: include dogs of predisposed breeds, geriatric population. Treatment is not recommended.

Stage B1: These are animals with MR but no cardiomegaly. Does not exist medicinal product, slowing down the degenerative process in the valves. Treatment is not recommended.

Stage B2: These are dogs with MR, cardiomegaly, but no clinical signs. There is no agreement among experts on whether ACE inhibitors should be prescribed, as there are currently two veterinary studies SVEP (2002) and VETPROOF (2007) with conflicting results.

Stage C1: include animals with clinical signs heart failure requiring hospitalization. This may be a manifestation of the disease (signs appear for the first time after an asymptomatic period) or its exacerbation after remission. An exacerbation may be due to a torn tendon or LA, arrhythmia, excessive exercise, increased salt intake, or progression of the disease. ACVIM reached consensus on the following drugs: furo-semide (in / in, in / m, s / c) 1 ... 4 mg / kg BW or infusion at a constant rate of 1 mg / kg BW / h (the effectiveness of treatment is assessed by the frequency of respiratory movements and shortness of breath); pimobendan PO 0.25.0.3 mg/kg BW 12 hours later (based on clinical experience). There is no agreement on the use of ACE inhibitors, dobutamine, nitroglycerin ointment.

Stage C2: These are symptomatic dogs that can be treated at home. ACVIM reached consensus on the use of the following drugs: furosemide 1.2 mg/kg BW PO after 12 hours to 4.6 mg/kg BW PO after 8 hours, pimobendan 0.25.0.3 mg/kg BW after 12 hours, ACE inhibitor 0.5 mg/kg BW q 12 h, enalapril 0.5 mg/kg bw q 12 h), spironolactone (most ACVIM members approved). There is no expert agreement on the use of digoxin, beta-blockers, diltiazem, bronchodilators, amlodipine (0.1 mg / kg BW after 12 hours), hydrochlorothiazide (2.4 mg / kg BW after 12 hours), torasemide (0.2 mg / kg MT at 12.24 h).

Stage D1: refers to dogs with symptoms of congestive heart failure and/or reduced cardiac output requiring hospitalization. ACVIM reached consensus on the use of the following agents: furosemide IV bolus > 2 mg/kg BW or at a constant rate of 1 mg/kg BW/h (use with caution when serum creatinine is greater than 2.3 mg/dL); pimobendan 0.2...0.3 mg/kg BW after 12 hours. Amlodipine (0.05.0.1 mg/kg BW per os, after 12 hours) is added to therapy with high blood pressure. Try not to lower systolic pressure less than

Rice. 10. Electrocardiogram (lead II) of a patient with chronic UA insufficiency.

Signs of LA and LV hypertrophy

Rice. 11. Electrocardiogram (lead I) of a patient with chronic UA insufficiency.

Single ventricular extrasystole

85 mmHg Art. and average pressure - less than 60 mm. If necessary, add pimobendan or do-butamine. There is no agreement among experts regarding the use of ACE inhibitors, nitroglycerin ointment, high doses of pimobendan (0.3 mg/kg BW every 8 hours), dobutamine (2.15 mgk/kg BW/min).

Stage D2: These are patients refractory to standard therapy, with the possibility of treatment at home. ACVIM reached consensus on the use of the following drugs: furosemide from 1.2 mg/kg BW po after 12 hours to 4.6 mg/kg BW po after 8 hours. The use of torasemide is partially agreed. Recommended hypothiazide 1.2 mg every 12.24.48 hours; spironolactone 2 mg/kg BW every 12 hours, ACE inhibitors, pimobendan. There is no agreement on the following drugs: digoxin, spironolactone, sildenafil (from 0.5.1 mg/kg BW at 12 h to 2.3 mg/kg at 12 h), bronchodilators (aminophylline 10 mg/kg BW at 8 h, theophylline with a slow release of 20 mg/kg BW after 24 hours).

Thus, chronic insufficiency of atrioventricular valves as a result of myxomatous degeneration is a chronic process that requires an integrated approach to diagnosis with the definition of the stage of the process. The development of therapeutic measures is based on the obtained diagnostic data. The tactics of treatment depends on the stage of the pathological process and the monitoring of the animal's condition during the treatment of the disease.

Bibliography

1. Atkins, C.E. Pharmacologic management of myxomatous mitral valve disease in dogs / C.E. Atkins, J. Haggstrom // Journal of Veterinary Cardiology, - 2012 - V. 14. - N. 1. - P. 165-184.

2. Aupperle, H. Pathology, protein expression and signaling in myxomatous mitral valve degeneration: Comparison of dogs and humans / H. Aupperle, S. Dis-atian // Journal of Veterinary Cardiology. - 2012-V. 14. - N. 1. - P. 59-71.

3. Borgarelli, M. Historical review, epidemiology and natural history of degenerative mitral valve disease / M. Borgarelli, J.W. Buchanan // Journal of Veterinary Cardiology. 2012 - V. 14. - N. 1. - P. 93-101.

4. Borgarelli, M. Survival characteristics and prognostic variables of dogs with pre-clinical chronic degenerative mitral valve disease attributable to myxomatous degeneration / M. Borgarelli, S. Crosara, K. Lamb, P. Savarino, G. La Rosa, A. Tarducci, J. Haggstrom / J Vet Intern Med. - 2012 Jan-Feb. - V. 26. - N. 1. - P. 69-75.

5. Chetboul, V. Echocardiographic assessment of canine degenerative mitral valve disease / V. Chetboul, R. Tissier // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 127-148.

6. Connell, P.S. Differentiating the aging of the mitral valve from human and canine myxomatous degeneration / P.S. Connell, R.I. Han, K.J. Grande-Allen // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 31-45.

7. Dillon, A.R. Left ventricular remodeling in preclinical experimental mitral regurgitation of dogs / A.R Dillon., L.J. Dell'Italia, M. Tillson, C. Killingsworth, T. Denney, J. Hathcock, L. Botzman // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 73-92.

8. Fox, P.R. Pathology of myxomatous mitral valve disease in the dog / P.R. Fox // Journal of Veterinary Cardiology. - 2012-V. 14. - N. 1. - P. 103-126.

9. Jepsen-Grant, K. Vertebral heart scores in eight dog breeds / K. Jepsen-Grant, R.E. Pollard, L.R. Johnson // Vet Radiol Ultrasound.-2013 Jan-Feb. - V. 54. - N. 1. - P. 3-8.

10. Kellihan, H.B. Pulmonary hypertension in canine degenerative mitral valve disease / H.B. Kellihan, R.L. Stepien // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 149-164.

11. Orton, E.C. Mitral valve degeneration: Still more questions than answers / E.C. Orton // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 3.

12. Orton, E.C. Signaling pathways in mitral valve degeneration / E.C. orton,

C.M.R. Lacerda, H.B. MacLea // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 7-17.

13. Parker, H.G. Myxomatous mitral valve disease in dogs: Does size matter? / H.G. Parker, P. Kilroy-Glynn // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 19-29.

14. Richards, J.M. The mechanobiology of mitral valve function, degeneration, and repair / J.M. Richards, E.J. Farrar, B.G. Kornreich, N.S. Mo "ise, J.T. Butcher // Journal of Veterinary Cardiology. - 2012 - V. 14. - N. 1. - P. 47-58.

15. Singh, M.K. Bronchomalacia in dogs with myxomatous mitral valve degeneration / M.K. Singh, L.R. Johnson, M.D. Kittleson, R.E. Pollard // J Vet Intern Med. - 2012 Mar-Apr. - V. 26. N. 2. - P. 312-319.

SUMMARY V.K. Illarionova

Veterinary Clinic "Biocontrol" (Moscow).

Myxomatous Mitral Valve Disease in Yorkshire Terriers. The article considers one of the most common heart disease in Yorkshire Terriers - myxomatous mitral valve disease, or endocardiosis. The pathophysiology of heart failure, the main criteria of diagnostics of this disease and approaches to the treatment of dogs with different stages of heart failure is described.

efficient distribution AS-Market is the exclusive supplier of Allervet 1%

(ANep/Esht 1%, diphenhydramine), 50 ml, injectable, for veterinary use.

AS group of companies The drug is prescribed for small household

animals and young animals of agricultural animals for the prevention and relief allergic reactions with serum sickness, anaphylaxis, anaphylactic shock, itching and atopic dermatitis, allergic conjunctivitis, rhinitis, polyarthritis, articular and muscular rheumatism, as a sedative in combination with sleeping pills, for diseases of the respiratory system, genitourinary tract, for premedication before general anesthesia.

Phone +7 /495/ 916-91-64, www.as-market.ru

ELKAROLIN- ■

T"< фо«с М ОО 314 ПК

YalaizishiiYa

(AHervetum 1%) sterile AL injection

"001 g YARO*.:*-

i^"*"lramiio xxunuewowcc*?*

with temlersgus * "

MD MK is a disease characterized by compaction of the mitral valve leaflets, which prevents their complete closure and contributes to the occurrence of regurgitation (reverse flow) of blood into the cavity of the left atrium.

1 Anatomical data about the heart as an organ

For more than 30 years, there has been a so-called heart-lung machine, which for a short time, but can replace the pumping function of the heart, although, of course, it cannot be completely replaced. And this fact makes us worry about the body's motor, because without it it will not be possible to live.

For mammals of the order of primates, to which humans belong, a 4-chambered heart is characteristic, i.e. it consists of 4 chambers - 2 ventricles (left and right), and 2 atria (also left and right). The right parts of the heart are responsible for pumping blood through the so-called "small" circle of blood circulation, i.e. heart - lungs (in which the blood is enriched with oxygen); and from the left departments the blood enters " big circle”, i.e. left atrium - left ventricle - body.

The right atrium communicates with the right ventricle through the tricuspid (tricuspid) valve, and the left atrium communicates with the left ventricle through the mitral (bicuspid) valve, the defeat of which will be discussed in this article.

2 Causes of the disease

The exact cause of myxomatous degeneration of the mitral valve is not known, often this pathology is associated with a hereditary predisposition. Most often, this disease affects people who have impaired cartilage formation, birth defects and joint diseases.

In recent years, scientists have associated degeneration of the mitral valve (myxomatosis of the mitral valve) with hormonal disorders of various origins. There is also a certain connection between this pathology and various viral diseases that have a damaging effect on the cusps of the heart, as well as streptococcal infection, which causes direct damage not only to the valvular apparatus, but also to the endocardium of the heart.

3 Pathogenesis of the development of the disease

Stretching and thickening of the mitral valve cusps causes a violation of the closure of the latter, which contributes (due to higher pressure in the left ventricle than in the left atrium) backflow of blood into the cavity of the left atrium. This, in turn, causes hyperfunction with subsequent hypertrophy of the left atrium and relative insufficiency of the valves of the pulmonary veins, and subsequently hypertension in the pulmonary circulation, which causes most of the symptoms of this disease.

Depending on the thickness of the valve leaflets, the following stages of the disease are distinguished:

I degree - the leaflets are thickened up to 3-5 millimeters, while the closure of the valve is not disturbed, therefore the patient has no clinical manifestations, because of this, it is possible to identify the disease at this stage only when examining diseases of other systems or during preventive examinations.

No special treatment for myxomatosis of the mitral valve of the 1st degree is required, even restrictions on physical activity are not given, the main thing is to lead a healthy lifestyle, try not to get sick with various viral and streptococcal infections and periodically conduct preventive examinations (most often recommended 2 times a year).

II degree - the thickening of the valves reaches 5-8 millimeters, the closure of the valve is broken, there is a reverse reflux of blood. Also, the examination revealed single detachments of the chord and deformation of the contour of the mitral valve. At this stage, the doctor describes the lifestyle, nutrition and frequency of preventive examinations.

III degree - the thickening of the valves exceeds 8 millimeters, the valve does not close, there are complete detachments of the chord. At the same time, the patient's condition deteriorates sharply, symptoms of acute left ventricular failure appear, so emergency specialized treatment of this patient is needed, and at this stage it is very important to seek medical help early.

4 MK degeneration - clinical manifestations

The clinical picture of this disease directly depends on the stage of the disease and the degree of compensation of the organism.

The first degree in the vast majority of cases has no clinical manifestations, since there is no regurgitation (reverse reflux of blood) and, in general, the hemodynamics of the body is not disturbed. There may, of course, be common symptoms - dizziness, increased fatigue, decreased exercise tolerance - but these symptoms occur in a huge variety of other diseases and even in completely healthy people.

In the second degree, there are already small detachments of the chord, and there is also regurgitation, although its level is not critical, but physiologically and clinically the patient will feel it. There is a decrease in working capacity, general weakness, shortness of breath during physical exertion, and at such a load, in which there were no such symptoms before (for example, rising to the third floor).

Also, such patients may be disturbed by tingling in the region of the heart, rhythm disturbance, which also begins after a short physical exertion.

But all these symptoms may not be, if you notice at least a few of these of them, then you should immediately consult a doctor, because early treatment increases the chances of a full recovery several times.

For the third degree, due to the depletion of the compensatory ability of the body, all of the above symptoms are characteristic, but since, due to the complete separation of the chord, the closure of the valves is severely impaired or absent at all, the symptoms will be very pronounced. The patient complains of severe shortness of breath even with the slightest physical exertion, and is also sometimes bothered by a cough, often frothy, streaked with blood.

Disturbed by dizziness, which often leads to fainting. Sometimes patients are concerned about angina pectoris pain in the region of the heart, which does not subside even after taking nitrate drugs such as nitroglycerin. At this stage, any delay in the provision of qualified medical care may lead to death.

5 Diagnostic algorithm for suspected MD MK

Mitral valve degeneration is diagnosed on the basis of the patient's complaints, which we discussed above (in the section "MV Degeneration - clinical manifestations”), but even in their absence, the patient should be examined by special methods, which we will discuss below.

Next, the doctor prescribes general clinical tests for the patient, such as a complete blood count, a complete urinalysis, and a biochemical blood test. Most often, there are no changes in them, but with a third degree of insufficiency in general analysis anemia can be detected in the blood, or vice versa, signs of blood clotting (an increase in the level of red blood cells, platelets, hemoglobin and a decrease in the level of ESR), this is due to the release of the liquid part of the blood into the third space (lungs).

The "gold" standard for detecting valve insufficiency and chord rupture is an ultrasound examination of the heart with dopplerometry. This method allows you to identify the stage and degree of decompensation of the disease, and this can be done even before the child is born, which means it is early to identify and prescribe early treatment.

Not highly specific methods, but necessary for the early diagnosis of the disease, are an ECG study and an X-ray examination of the chest organs. In the first case, we will reveal signs of hypertrophy of the left parts of the heart, and the hypertrophy of the right parts of the heart will also join the third stage, various supraventricular tachyarrhythmias such as atrial fibrillation or flutter, supraventricular extrasystoles are also detected.

And on x-ray, there will be signs pulmonary hypertension, bulging of the left atrial arch, as well as expansion of the boundaries of the heart (in the third stage, the development of a "bull" heart).

To clarify the diagnosis, special research methods can be used - catheterization of the left and right ventricles, as well as left ventriculography, which will help clarify the presence of the disease and its degree.

6 Modern treatments

Treatment of mitral valve degeneration depends on the stage and degree of compensation of the body, and this directly depends on the patient's seeking help from a doctor. At the first stage, special treatment is not required, it is enough to follow a healthy lifestyle, limit yourself to exorbitant physical activity, stick to proper nutrition and limit yourself to salty foods.

In the second stage, treatment is not limited in a healthy way life and nutrition. After establishing the diagnosis and identifying the degree of decompensation, doctors prescribe various cardiotonic drugs, which are designed not only to improve hemodynamics, but to relieve the left heart. In the second stage, treatment is most often limited to medications.

In the third stage, it is difficult to limit treatment only with medications, therefore, surgical intervention is necessary to replace the valve, and an early operation is desirable in order to avoid damage to other organs, since heart disease to one degree or another affects all body systems.

These operations, although they are high-tech, most often pass without serious complications, so you need to decide on an operation for your own health.

Remember! Early treatment of the disease is the key to a long life!