Diagnosis of mitral valve prolapse

Diagnosis of mitral valve prolapse is carried out on the basis of a comprehensive clinical and instrumental examination, including the analysis of subjective manifestations, typical auscultatory data and echocardiographic signs.

A characteristic auscultatory sign of mitral valve prolapse is a systolic click ("click"), caused by sudden tension of the affected leaf or tendon threads at the time of its rapid prolapse into the atrium. This occurs in conditions of maximum contraction of the left ventricle and a decrease in its cavity. With PMK, a mesosystolic or late systolic click is heard in the region of the apex of the heart. An earlier occurrence of a click in the systole can be observed with a Valsalva test, a sharp transition of the body to an upright position. An exhalation, a test with a raising of the legs above the horizontal level, contributes to a later occurrence of a click and a decrease in its intensity. With the development of mitral regurgitation, late systolic murmur joins the systolic click.

The main electrocardiographic disorders with mitral valve prolapse are nonspecific and include changes in the end part of the ventricular complex - isolated inversion of the T-wave in leads II, III, AVF without segment displacement. Inversion of the T-wave in the leads from the extremities and left thoracic leads (V5-V6), combined with a slight ST shift below the isoline, indicates the presence of latent myocardial dysfunction, the frequency of which rises by a factor of 2 when the standard ECG is recorded in an upright position. The appearance of the above changes in the orthostatic position is associated with the tension of the papillary muscles due to the emerging tachycardia, a decrease in the volume of the left ventricle, and an increase in the depth of prolapse of the valves. Repolarization defects in mitral valve prolapse are variable in nature and disappear when a loading pharmacological test with a beta-adrenoblocker is performed, which indicates a sympathetonic genesis of the described changes. Heart rhythm disturbances include the recording of supraventricular, ventricular extrasystole and arrhythmias, conduction disorders - prolongation of the QT interval, incomplete blockade of the right bundle of the bundle.

The main method of diagnosis of mitral valve prolapse is transthoracic echocardiography in M and B regimens. A typical echocardiographic pattern involves the displacement of one or both of the mitral valve flaps upward and posteriorly over the plane of its ring during systole into the left atrial cavity by more than 2 mm. Prolapse of the valve is more often observed in the middle of the systole. It is not necessary to diagnose mitral valve prolapse in the absence of a typical auscultatory pattern and thickening of the valves in case of shallow prolapse by the clotting flap located along the ventricular side from the plane of the mitral ring.

According to the recommendations of the American Heart Association (2006), there are the following indications for the use of echocardiography:

• presence of auscultatory signs of mitral valve prolapse;
• risk stratification in patients with diagnosed PMC:
• Exclusion of PMC in people with atypical clinical manifestations;
• a survey of relatives of patients of the first degree of kinship with the detected myxomatous changes in the valvular apparatus.

Diagnostic criteria for mitral valve prolapse are based on the auscultatory pattern and echocardiographic examination.

[1], [2], [3], [4], [5]

Diagnostic criteria for mitral valve prolapse

Types of criteria	Methods of research	Manifestation
Big criteria	Auscultation	Mean systolic flicks and / or late systolic murmur
	Two-dimensional echocardiography	Systolic sagging of one of the clasts by more than 2 mm into the cavity of the left atrium. Moderate displacement of one of the valves to systole in combination; with chord rupture; mitral regurgitation; dilatation of the mitral ring
	Auscultation and echocardiography	Moderate displacement of one of the valves to systole in combination: with a pronounced medium- or late-systolic flick on the typhus; with late systolic or holosystolic murmur, which is heard at the apex of the heart of a young patient
Small criteria	Auscultation	Loud one tone with a hysterical murmur at the top of the heart
	Two-dimensional echocardiography	Isolated moderate displacement of the posterior wing to the systole Moderate displacement of both nodules to the systole
	Echocardiography and anamnestic data	Moderate systolic displacement of valves to systole in combination; with an episode of transient ischemic attack and / or blindness in a young patient; with the presence of relatives of the first kinship relationship, who have established large criteria

In the presence of one or two main criteria, the combination of auscultatory and echocardiographic signs allows to diagnose mitral valve prolapse. In the case of only small criteria, the probable prolapse of the mitral valve is assumed.

Primary PMC can be combined with the phenotypic signs of connective tissue dysplasia, in this connection, the variant of undifferentiated STD - MASS-phenotype (Mitral valve, Aorta, Skin, Skeletal) with aorta, skin and musculoskeletal system is distinguished. The frequency of detection of external and internal phenotypic signs of connective tissue dysplasia depends on the thoroughness and purposefulness of the examination. Currently, the unified term for undifferentiated connective tissue dysplasia is the "hypermobility syndrome", based on the diagnosis of hypermobility of joints (the Beaton scale) as the most characteristic sign of generalized inconsistency of connective tissue and a complex of phenotypic markers of STD, including PMC.

Brighton criteria for hypermobile syndrome in the modification of A.G. Belenkogo (2004)

Great criteria: 

• account on the scale of Beiton 4 of 9 or more (at the time of inspection or in the past);
• arthralgia more than 3 months in four joints and more.

Small criteria:

• the score on the Beaton scale is 1-3 out of 9 (0-2 for people over 50);
• arthralgia in 1-3 joints or lumbargia for more than 3 months, the presence of spondylolysis, spondylolisthesis;
• dislocation or subluxation in more than one joint or repeated dislocation in one joint;
• periarticular lesions of more than two localizations (epicondylitis, teposinovitis, bursitis, etc.);
• marfanoid (high growth, leanness, arm / height ratio greater than 1.03, ratio of upper / lower body segment less than 0.83, arachnodactyly);
• mitral valve prolapse;
• eye signs: overhanging eyelids or myopia;
• varicose veins, or hernia, or omission of the uterus or rectum;
• skin signs: thinness, hyperextension, striae, atrophic scars;
• hollow foot, brodhodactyla, deformity of the thorax, sandal-shaped prominent fissure of the foot;
• scoliosis;
• Hallux valgus.

Hypermobility syndrome is diagnosed if there are two large criteria, or one large and two small criteria, or four small ones. Two small criteria are sufficient if the relative of the first line of relationship has signs of STD. The diagnosis of hypermobile syndrome is excluded when there are signs of differentiated STD.

[6], [7], [8], [9]