[Idiopathic mitral valve prolapse]

Current knowledge concerning idiopathic prolapse of the mitral valve is illustrated. The histopathological cause is myxoid degeneration of the mitral cusps, which sometimes extends to the tendinous cords, the valve implant ring, and the apex of the papillary muscles. Primary damage to these structures, whose intactness is essential for correct closure of the ostium, causes protrusion of the ventricular cusps into the left atrium during ventricular systole (i.e. prolapse). The reason for this degeneration is not known. The high familial incidence of prolapse lends credit to the most widely held suggestion, namely a hereditary defect. The clinical progress is benign in the great majority of cases ("crystallized" form) and is often asymptomatic. Complications are possible, however, and must always be borne in mind. They include progressive and acute mitral insufficiency, infective endocarditis, arrhythmias, motor or sensitive neurological complications, and sudden death. Particular attention must be paid to the path to be followed to arrive at the correct diagnosis. Careful evaluation of some of the clinical signs arousing suspicion in the previous history and/or objective examination enable a diagnosis to be formed with relatively simple, non-invasive instrumental techniques, such as echocardiography and polycardiography, provided other forms of prolapse secondary to ischaemic heart disease, mitral endocarditis, etc. are excluded. "Therapy is obviously necessary in the presence of complications; however, even in "crystallized" form, in the presence of subjective symptoms, tranquillizers and possibly beta-blockers may be necessary".