Association between congenitally quadricuspid aortic valve and mitral valve prolapse.

We describe transthoracic echocardiograms in three patients with combined quadricuspid aortic valve and prolapsing mitral valve. None had symptoms of cardiac dysfunction. Two patients had precordial murmurs. A third patient was referred for evaluation of infective endocarditis. The fact that a quadricuspid aortic valve is clearly a congenital anomaly supports the view that mitral valve prolapse is a congenital anomaly that may be more strongly associated with quadricuspid aortic valves than once thought.