MITRAL VALVE PROLAPSE

Mitral valve prolapse

In the early 1980s, the increasing availability of ECO and incomplete knowledge was responsible for a large number of false diagnoses of mitral valve prolapse syndrome (Barlow syndrome). The epidemic of false diagnoses also extended to the sports population, giving rise to a series of innocent victims, namely female athletes and athletes who, in some centers, were systematically denied fitness for sport for the simple fact of being carriers of the echocardiographic signs of the syndrome.
Although mitral valve prolapse (PVM) still remains the most frequent valve anomaly in sports medicine, in the following years, the problem has been considerably reduced,
Sports doctors have learned to "manage", in most cases, sportsmen with mitral valve prolapse and to turn to Level II and III Centers only when there are disputes between the various consultants and / or the "anomaly is of a significant degree. The approach to a sportsman with PVM is based, in fact, on two main aspects:

- a correct diagnosis (in the high-level athlete the problem may be less serious than one thinks, training can in fact induce significant changes in the clinical-instrumental picture);

- the prognostic evaluation for the purposes of the judgment of fitness for sporting activity, considering that the anomaly often has a benign meaning, but is sometimes responsible for serious complications including, albeit rarely, sudden death from sports.

Definition of mitral valve prolapse

The term PVM defines the superior displacement or protusion of one or both mitral flaps in the left atrium during systole, caused by structural anomalies of the mitral apparatus (flaps, tendon cords, muscles, papillaries, annulus). of protrusion, and the consequent alteration of the dynamics of the valve leaflets, can vary from mild to severe and be responsible for valvular regurgitation, which is also variable but usually modest.
This definition of mitral valve prolapse would seem simple and exhaustive, but it is not if we consider that the main element consists of an exclusively anatomical, spatial aspect, namely the abnormal protrusion of the mitral flaps into the left atrium, whose real however, the definition is far from easy. For example, to define the PVM, the Anglo-Saxon authors used other terms besides the initial mitral valve prolapse, such as floppy valve, billowing mitral valve, flail valve, terms not always equivalent to each other , which in the past generated a certain confusion in the same scholars.
Currently, the term "floppy valve" is reserved for cases with evident structural alterations of the valve (elongation and redundancy of the flaps) and significant mitral insufficiency, "that is, for cases that we define as" true prolapse or serious prolapse ". The term "flail valve" (floating valve) indicates, instead, an even more serious condition, in which the rupture of one or more tendon cords causes the fluctuation in the "atrium of one or both flaps." The term PVM syndrome should be reserved cases in which the morpho-functional abnormalities of the valve are accompanied by signs and symptoms of autonomic and / or neuroendocrine dysfunction and / or other pathological signs such as arrhythmias.
The prevalence of mitral valve prolapse in the general population varies between 0.3 and 17%, but can be estimated on average around 4-6%. It mainly affects the female sex (ratio of about 2: 1 on average), with maximum concentration in subjects with "thin" habitus. In women, two prevalence peaks were observed in the third and fifth decade of life, respectively, while in men the peak is located in the second, after which a tendency to decrease with age is observed. The prevalence of PVM appears high also in pediatric age, in which the association with the previously reported habitus is equally evident. In an Italian study, carried out years ago in a student population, close in composition to the one that attends Sports Medicine clinics, ECO 2D aspects of PVM they were present in 6.4% of cases, but only 0.5% had a "true prolapse" (with redundant flaps, dilated annulus, etc.).
The prevalence of mitral valve prolapse has also been investigated in the high-level competitive sports population. The first study was that of the 1976 Montreal Olympics which showed an "alarming" prevalence (22%). In the study of the Institute of Sports Science , the prevalence of PVM in probable Olympic athletes appeared to be 3.2%, a value similar to that of the general population. Prevalence is higher in athletes with long-limbed body habit and high stature. In a study, conducted on 60 players and 30 players of our national volleyball teams, the total prevalence was 23.3%, lower in men (18.3%) than in girls (33.3%). The "high prevalence in the latter" confirms what was observed many years earlier in basketball players. On the other hand, using selective ECO criteria, mitral valve prolapse was found in about 7% of children and adolescents practicing various sports, in particular in minibasketball (11%). Naturally, both in the general population and in the sports one, the prevalence of PVM rises significantly if outpatient cases are taken into consideration, ie made up of subjects who came to observation not by chance but due to ECG anomalies and / or subjective disturbances.
On the ECG, anomalies of the ventricular repolarization phase can be found, mainly involving the T wave and the ST segment, and rhythm disturbances, mostly ventricular extrasystoles. A subject with isolated mitral prolapse (i.e. not associated with other heart diseases) can be considered suitable for sports when no signs of compromised myocardial contractility are detected. It should be remembered that, regardless of sports fitness problems, these subjects must still be reassured about their condition, especially considering the benignity of the disease.

Hypertrophic cardiomyopathies, diseases of the heart muscle of unknown etiology, characterized by hypertrophy of the interventricular septum (asymmetrical form) or of the posterior wall of the left ventricle, as well as of the septum (symmetrical form) are always an absolute contraindication to sporting activity.
The finding of a systolic murmur at the cardiac apex and along the left marginosternal line, or the appearance of symptoms such as dyspnea on exertion, dizziness, syncopal attacks, associated with graphic ECG signs require an accurate diagnostic investigation in order to confirm or exclude the presence of hypertrophic cardiomyopathy.
Murmurs of venous origin are to be considered of a benign nature; they are heard in the upper and subclavicular area, and are modified or disappeared with flexion or extension of the neck or with abduction of the shoulders.

Curated by: Lorenzo Boscariol

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