The cumulative risks of prolapsing mitral valve. 40 years of follow-up.

Prolapsing mitral valve is a common cardiac condition, occurring in approximately 16 million people in the United States alone. Primary prolapsing mitral valve may be familial or nonfamilial and may be associated with myxomatous degeneration of the mitral valve leaflets, such as occurs in Marfan syndrome and other connective tissue disorders. Secondary forms may be associated with such entities as rheumatic fever (especially after commissurotomy) and coronary artery disease (in the presence of ruptured chordae tendineae), and with such congenital conditions as interatrial defect and primary cardiomyopathy with outflow tract obstruction. Prolapsing mitral valve is characterized by late systolic murmur, mid-systolic click, or both. Arrhythmias occur in the form of benign premature atrial contraction, premature nodal contraction, and paroxysmal atrial tachycardia. As the patient ages, atrial flutter and atrial fibrillation tend to develop. In some chronic cases, especially those involving atrial fibrillation, systemic emboli may occur. Rare premature ventricular contractions may be largely benign, whereas more frequent premature ventricular contractions may lead to severe arrhythmic complexes such as ventricular tachycardia or ventricular fibrillation. With advancing age, atrioventricular conduction defects of varying degrees or sick sinus syndrome may necessitate a pacemaker installation. About one quarter of prolapsing mitral valve cases progress, with increasing mitral insufficiency and increasing enlargement of the left atrium and left ventricle, which at times leads to congestive heart failure. Coronary artery disease may occur with the severity commensurate with the patient's age group. About three quarters of patients with prolapsing mitral valve syndrome lead normal lives.