Mitral valve prolapse and arrhythmia

Mitral valve prolapse (mitral valve prolapse, PMK) is a deflection of the valve cusps during systole into the cavity of the left atrium.The spread of the disease among all cardiovascular anomalies is about 1–4% (D. Savage, 1983; R. Devereux et. A, 1987; D. Levy, D. Savage, 1987). PMK often does not pose a serious threat to the health of the patient, but in some cases complications such as bacterial endocarditis, thromboembolism, mitral regurgitation develop.

The combination of mitral valve prolapse with various forms of arrhythmia is most often observed in 42–75% of the total number of cases (Storozhakov, G.I. et al., 1978; Levanto, L.I., Fomin, EL., 1988; M.Swartz, e. a, 1977).

At present, the mechanisms of development of arrhythmias during mitral valve prolapse have not been precisely established. Also, the clinical significance of the arrhythmic syndrome in MVP is not fully known. Nevertheless, in order to prevent deterioration in patients with MVP, it is worth getting acquainted with the information presented below.

Video: Arrhythmic Mitral Valve Prolapse

General characteristics of mitral valve prolapse

Mitral valve prolapse (MVP), also known as flexible mitral valve syndrome, systolic flick syndrome and heaving mitral cusps, is a disease of the valvular apparatus of the heart. This is a benign condition that in rare cases can lead to sudden cardiac death, endocarditis, or stroke.

PMK is usually determined during the medical examination of the patient. Echocardiography confirms the diagnosis.This disorder is the most common cause of non-ischemic mitral regurgitation in developed countries. Sometimes patients with severe symptoms may need to restore the mitral valve.

Causes of mitral valve prolapse

The specific primary mechanism responsible for the PMH is unknown. However, evidence suggests that various changes in the mitral valve or the lower left heart chamber (left ventricle) can lead to MVP. Such abnormalities may include excess mitral valve flap (flap) and / or tendon elongation (tendon chord), which attach the flap to specific muscles (papillary muscles) of the ventricle.

PMK usually occurs as an isolated condition in connective tissue diseases:

• Marfan syndrome.
• Lois-Ditz syndrome.
• Ehlers-Danlos syndrome.
• Osteogenesis imperfecta.
• Elastic pseudoksantom.
• Aneurysm syndrome-osteoarthritis.

In autosomal dominant disorders, it may happen that one copy of the disease gene (obtained from the mother or father) “dominates” the other normal gene and leads to the appearance of the disease. The risk of transmitting the disorder from the affected parent to the offspring is 50% and it does not depend on the sex of the child. The risk is the same for every pregnancy.

Cardiac abnormalities potentially associated with MVP may include:

• Heart muscle disease (cardiomyopathy).
• Heart failure or damage due to constriction or blockage of the arteries supplying the heart muscle (ischemic heart disease).
• An abnormal opening in the fibrous septum that normally separates the two upper chambers of the heart (i.e., certain atrial septal defects).
• Rheumatic heart disease.

Rheumatic heart disease is damage to the heart muscle and heart valves caused by acute rheumatic fever, an inflammatory disease that can occur as a delayed reaction to infection with streptococcal bacteria (ie, beta-hemolytic streptococcus group A).

Although mitral valve prolapse occurs in people of different ages, it is most often diagnosed in young people. Estimates show that MVP affects approximately 4–8% of young people in the general population, with women being more affected than men.

People with PMK, as a rule, have a low body mass index and are more often more thin than those who do not have this heart disease. PMK can be associated with significant mitral regurgitation (4%), bacterial endocarditis, congestive heart failure, and even sudden death.

In most patients with MVP, mitral valve regurgitation is either mild or insignificant.

Valve closure is normal (top) and with mitral valve prolapse (bottom).

Pathophysiological and histological changes

PMK is the primary myxomatous degeneration of one or both mitral valve leaflets. Destruction of the endothelium leads to complications, such as infective endocarditis and thromboembolism. Most patients with MVD have minimal disruption of the mitral valve structure, which does not cause serious health complications.

Histologically, PMK is defined as myxomatous lesion. Mucopolysaccharide deposits and excessive water content are determined in the structure of the mitral valve leaflets. This leads to thickening and enlargement of the flaps. The content of type III collagen is increased, and the elastin fibers are fragmented, which affects the functionality of the valve.

Symptomatology

PMK is most often associated with atypical chest pain , as well as palpitations, shortness of breath on exertion and intolerance to exercise. Other symptoms, such as anxiety, low blood pressure and syncope , indicate dysfunction of the autonomic nervous system. Sometimes there are supraventricular arrhythmias , indicating an increase in parasympathetic tone.

When PMK during auscultation for the mid-systolic click follows systolic murmur. This change is usually heard at the top of the heart and often depends on the position of the patient.

• Noise increases when the patient stands and performs a Valsalva maneuver, that is, tries to exhale through the nose when it is closed and, of course, with its mouth closed. At the same time systolic click comes earlier, and noise becomes longer.
• The manifestation of manifestations decreases when the patient squats (systolic click comes later, and the noise becomes shorter).

It should be noted that the noise in PMK is similar to the noise in hypertrophic cardiomyopathy. At the same time mid-systolic click is a characteristic sign of mitral valve prolapse.

Video: Mitral Valve Prolapse and Regurgitation, Animation

Arrhythmias in mitral valve prolapse

The occurrence of arrhythmia in the background of MVP depends mainly on the state of the vegetative nervous system (ANS) and vegetative regulation. In particular, there may be a decrease in the level of vegetative reactivity and an increase in the tone of the sympathetic ANS.

Some researchers note that the greater the severity of sympathicotonia, the more often arrhythmia occurs, regardless of the state of the valvular apparatus.

Forms of arrhythmias that can occur with mitral valve prolapse:

• Ventricular extrasystoles - very often.
• Supraventricular extrasystoles - often.
• Migration pacemaker - often.
• Paroxysms of supraventricular tachycardia - rarely.
• Short episodes of ventricular tachycardias are rare.
• Paroxysms of atrial fibrillation - rarely.
• Ventricular parasystole - rarely.
• Sinus arrhythmia and sinus tachycardia.

Life-threatening arrhythmias, such as ventricular fibrillation, most often develops with local organic changes in the myocardium that may accompany the MVP. Single rhythm disturbances, as a rule, are not dangerous to the health of the patient.

Sinus arrhythmia on ECG.

Diagnostics

The most useful method for making a diagnosis of MVP is echocardiography. M-Mode echocardiography is not used to diagnose PMK. This is because the normal movement of the base of the heart can imitate or mask a heart defect. Two- or three-dimensional echocardiography allows to measure the thickness and displacement of the valves relative to the ring.

A mitral valve prolapse is established when the displacement of the mitral valve is determined by more than 2 mm above the mitral ring in the form of a long axis. PMK is also subdivided into non-classical and classically thick mitral valve cusps. In non-classical PMK, the thickness of the mitral valve leaflet is from 0 mm to 5 mm. In the classic case, the mitral valve leaflets are more than 5 mm thick.

Classical PMK is divided into symmetrical and asymmetrical , depending on the point at which the tips of the leaflets are connected to the mitral ring. With a symmetrical shape, the tips of the leaflets are found at a common point of the ring, and with an asymmetric shape, one leaflet is displaced towards the auricle relative to the other.

Magnetic resonance imaging (MRI) is not often used in the diagnosis of PMH. This study, as a rule, allows you to quantify mitral regurgitation before surgery on the mitral valve.

Sometimes PMK is detected randomly on the left ventriculography during cardiac catheterization. In such cases, is determined by the displacement of the mitral valve in the left atrium with late systolic regurgitation of the mitral valve. In such people, PMK is further assessed using echocardiography.

If there is a discrepancy between clinical and echocardiographic data on the degree of mitral valve regurgitation, then cardiac catheterization and left ventriculography are recommended.

In the presence of concomitant diseases, additional research methods may be prescribed by the type of chest radiography. In particular, if a hidden arrhythmia is suspected, Holter ECG monitoring may be indicated. It may also be useful to test with FN, which allows you to confirm the functional nature of rhythm disturbances.

Video: Echo-Web - Mitral Valve Prolapse

Treatment

Patients with mitral valve prolapse and in the absence of symptoms often do not need treatment.

Directions in the treatment of patients with mitral valve prolapse and arrhythmias:

• Patients with PMK in the presence of symptoms by type of disavtomony (chest pain, palpitations) are most often prescribed beta-blockers, such as propranolol. Similar means are especially shown in case of definition of frequent and heavy ventricular ectopias.
• Cardioverter defibrillator is recommended for implantation in patients with CMD and sustained ventricular arrhythmias.
• Catheter ablation of ventricular arrhythmias is indicated in patients with frequent ventricular ectopia associated with symptoms or dysfunction of the left ventricle, and ventricular tachycardia, or even ventricular fibrillation (which may be caused by extraordinary impulses originating from the papillary muscle or Purkinje system).

MVK with severe mitral regurgitation may be susceptible to the restoration of the mitral valve or its complete replacement. According to the ACC / AHA recommendations, such mitral valve repair should be carried out before symptoms of congestive heart failure appear.

People with PMK have a high risk of bacterial endocarditis. Until 2007, the American Heart Association (AHA) recommended that antibiotics be prescribed to such patients before all invasive procedures, including dental operations.After that, the AHA decided that such prophylaxis should be used only when providing dental services to patients who have other heart conditions that put them at the greatest risk of adverse effects of infective endocarditis.

The connection between MVP and vascular cerebral is rather low. Based on this, the American Heart Association 2014 / American College of Cardiology (AHA / ACC) and the European Society of Cardiology 2012 do not recommend antiplatelet / antithrombotic therapy for MVP.

The 2006 ACC / AHA guidelines recommend aspirin for unexplained transient ischemic attacks with sinus rhythm, as well as no blood clots in the atria. Aspirin can be used for sinus rhythm with echocardiographic evidence of a high risk of MVP.

Anticoagulation is recommended for systemic embolism or recurrent transient ischemic attacks (TIA), in addition to aspirin therapy. Anti-coagulation is not recommended in the absence of systemic embolism, unexplained TIA, ischemic stroke or atrial fibrillation.

Prognosis and complications

The general prognosis for mitral valve prolapse is favorable. Most asymptomatic people do not know that they have a heart defect and their normal life is not disturbed.

Complications associated with MVP include infective endocarditis, mitral regurgitation, arrhythmia, transient ischemic event, or systemic embolism. The main predictor of mortality in MVP is the degree of mitral valve regurgitation and ejection fraction.

Almost all patients with suspected PMH are examined by a cardiologist, but if necessary, a referral to a cardiothoracic surgeon can be given.

Video: Mitral Valve Prolapse ¦ Treatment and Symptoms