The systolic click-murmur syndrome: clinical recognition and management.

The midsystolic click-late systolic murmur syndrome is a complex entity with variable manifestations that involves a primary process causing myxomatous degeneration of the mitral valve leaflet(s) and subsequent systolic mitral valve leaflet prolapse. Other cardiac diseases may cause mitral valve prolapse and regurgitation associated with a midsystolic click that mimics this primary syndrome. The prolapsing mitral valve leaflet(s) syndrome occasionally may be familial. Most patients are asymptomatic but some complain of chest pain, palpitation, dyspnea or fatigue. Prolapsing mitral valve leaflet(s) can be distinguished from other causes of systolic clicks and mitral regurgitation murmurs by the characteristic movement of the clikmurmur complex in systole with various hemodynamic interventions. The clinical diagnosis usually can be confirmed by echocardiography, which demonstrates the abnormally prolapsdrome usually is minimal but can be progressive and lead to the need for prosthetic valve replacement. Most symptomatic patients can be managed medically but some require cardiac catheterization to evaluate the possibility of coexistent coronary artery disease, to assess the degree of mitral regurgitation and to evaluate other associated cardiac lesions. All patients with this syndrome should receive antibiotic prophylaxis prior to any surgical or dental procedures. Those patients suspected of having arrhythmias should be evaluated by continuous ambulatory ECG monitoring and dangerous arrhythmias probably should be treated. The prognosis usually is excellent, but sudden death and rapidly progressive mitral regurgitation due to ruptured chordae tendineae have been reported. Although more than a decade has elapsed since the midsystolic click-late systolic murmur syndrome was first recognized, much remains to be learned about this common but complex clinical entity.