Rapidly progressive obstructive cardiomyopathy in infants with Noonan's syndrome. Report of two cases.

Two patients with hypertrophic obstructive cardiomyopathy and Noonan's syndrome are presented. Both patients were found at postmortem examination to have gross malformation of the mitral valve and obliteration of the left ventricle due to muscle hypertrophy. Each case demonstrated similar clinical, echocardiographic, and angiographic findings. The poor response to medical and surgical therapy are noted.