Mitral valve prolapse.

Mitral valve prolapse is a condition that is being recognized with increased frequency. It is not known whether its incidence is increasing, or whether we are better able to diagnose it today. In the idiopathic or familial variety, the mitral valve pathology is almost always that of myxomatous degeneration. Some authors have suggested the presence of a cardiomyopathy because of significant left ventricular dysfunction in many cases. Idiopathic prolapse occurs predominantly in females, often at a young age, and may be associated with chest pain, dyspnea, fatigue, presyncope, syncope, and/or sudden death. The clinical findings are variable and typically consist of a nonejection click and/or late systolic murmur, heard best at the cardiac apex. Diagnosis can be confirmed by echocardiography and/or ventricular cineangiography, the latter permitting accurate recognition of the anatomy of the prolapsed leaflets. The complications of infective endocarditis, severe mitral insufficiency, and life-threatening ventricular arrhythmias represent the major problems of management. It is important to distinguish the idiopathic form of mitral valve prolapse from that due to coronary artery disease and to realize that mitral valve prolapse may occur in Marfan's syndrome, Turner's syndrome, or in association with secundum atrial septal defect or ruptured chordae tendineae. Typical clicks and/or murmurs have also been described in patients with a history of rheumatic fever and in hypertrophic cardiomyopathy. Although much descriptive knowledge has accumulated over the past 15 years, many unanswered questions remain regarding the idiopathic type of prolapse. What is the nature and cause(s) of myxomatous degeneration? What is the relation of the valve pathology to the left ventricular dysfunction? What is the relation of both of these factors to disabling chest pain, electrocardiographic changes, and life-threatening arrhythmias? Hopefully, answers to these and other important questions regarding mitral valve prolapse will be forthcoming.