Diagnosis of mitral valve prolapse

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

A characteristic auscultatory sign of mitral valve prolapse is a systolic click, caused by a sudden tension of the affected valve or tendon threads at the moment of its sharp prolapse into the atrium. This occurs under conditions of maximum contraction of the left ventricle and a decrease in its cavity. With MVP, a mesosystolic or late systolic click is heard in the region of the apex of the heart. An earlier appearance of a click in systole can be observed during the Valsalva maneuver, a sharp transition of the body to a vertical position. Exhalation, a test with raising the legs above the horizontal level contribute to a later occurrence of a click and a decrease in its intensity. With the development of mitral regurgitation, a late systolic murmur joins the systolic click.

The main electrocardiographic abnormalities in mitral valve prolapse are nonspecific and include changes in the terminal part of the ventricular complex - isolated inversion of the T waves in leads II, III, AVF without segment displacement. Inversion of the T waves in the limb leads and left chest leads (V5-V6) in combination with a slight shift of ST below the isoline indicates the presence of latent myocardial dysfunction, the incidence of which increases by 2 times when recording a standard ECG in the vertical position. The appearance of the above changes in the orthostatic position is associated with tension of the papillary muscles due to the resulting tachycardia, a decrease in the volume of the left ventricle and an increase in the depth of prolapse of the cusps. Repolarization disturbances in mitral valve prolapse are variable and disappear during a pharmacological stress test with a beta-adrenergic blocker, which indicates the sympathotonic genesis of the described changes. Cardiac rhythm disturbances include the registration of supraventricular, ventricular extrasystole and arrhythmias, conduction disturbances - prolongation of the QT interval, incomplete block of the right bundle branch of His.

The main diagnostic method for mitral valve prolapse is transthoracic echocardiography in M- and B-modes. A typical echocardiographic picture includes displacement of one or both mitral valve leaflets upward and backward above the plane of its ring during systole into the left atrium by more than 2 mm. Leaflet prolapse is most often observed in mid-systole. Mitral valve prolapse should not be diagnosed in the absence of a typical auscultatory picture and thickening of the leaflets in the case of shallow prolapse with the closure line located on the ventricular side of 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 an established diagnosis of mitral valve prolapse:
• exclusion of mitral valve prolapse in individuals with atypical clinical manifestations;
• examination of first-degree relatives of patients with identified myxomatous changes in the valvular apparatus.

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

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Diagnostic criteria for mitral valve prolapse

Types of criteria	Research methods	Manifestation
Big criteria	Auscultation	Mid-systolic click and/or late-systolic murmur
	Two-dimensional echocardiography	Systolic prolapse of one of the cusps by more than 2 mm into the left atrium cavity Moderate displacement of one of the cusps during systole in combination with chord rupture; mitral regurgitation; dilation of the mitral annulus
	Auscultation and echocardiography	Moderate displacement of one of the valves during systole in combination with: a pronounced mid- or late-systolic click at the apex; with a late systolic or holosystolic murmur heard at the apex of the heart in a young patient
Minor criteria	Auscultation	Loud 1st tone with holosyptical murmur at the apex of the heart
	Two-dimensional echocardiography	Isolated moderate displacement of the posterior leaflet during systole Moderate displacement of both leaflets during systole
	Echocardiography and anamnestic data	Moderate systolic displacement of the valves during systole in combination with an episode of transient ischemic attack and/or blindness in a young patient with first-degree relatives who meet major criteria

In the presence of one or two major criteria, the combination of auscultatory and echocardiographic signs allows diagnosing mitral valve prolapse. In the case of only minor criteria, probable mitral valve prolapse is assumed.

Primary mitral valve prolapse may be combined with phenotypic signs of connective tissue dysplasia, in connection with which a variant of undifferentiated CTD is distinguished - MASS-phenotype (Mitral valve, Aorta, Skin, Skeletal) with damage to the aorta, skin and musculoskeletal system. The frequency of detection of external and internal phenotypic signs of connective tissue dysplasia depends on the thoroughness and focus of the examination. Currently, the unified term for undifferentiated connective tissue dysplasia is "hypermobility syndrome", based on the diagnosis of joint hypermobility (Beighton scale) as the most characteristic sign of generalized failure of connective tissue and a complex of phenotypic markers of CTD, including mitral valve prolapse.

Brighton criteria for hypermobility syndrome as modified by A.G. Belenky (2004)

Major criteria:

• Beighton scale score of 4 out of 9 or more (at the time of examination or in the past);
• arthralgia for more than 3 months in four or more joints.

Minor criteria:

• Beighton scale score 1-3 out of 9 (0-2 for people over 50);
• arthralgia in 1-3 joints or lumbago for more than 3 months, presence of spondylolysis, spondylolisthesis;
• dislocations or subluxations in more than one joint or repeated dislocation in one joint;
• periarticular lesions of more than two localizations (epicondylitis, teposynovitis, bursitis, etc.);
• marfanoid (tall stature, thinness, arm span/height ratio greater than 1.03, upper/lower body segment ratio less than 0.83, arachnodactyly);
• mitral valve prolapse;
• eye signs: drooping eyelids or myopia;
• varicose veins, or hernias, or prolapse of the uterus or rectum;
• skin signs: thinness, hyperextensibility, striae, atrophic scars;
• hollow foot, brachodactyly, chest deformity, sandal cleft foot;
• scoliosis;
• Hallux valgus.

Hypermobility syndrome is diagnosed in the presence of two major criteria, or one major and two minor criteria, or four minor criteria. Two minor criteria are sufficient if a first-degree relative has signs of TSD. The diagnosis of hypermobility syndrome is excluded in the presence of signs of differentiated TSD.

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