[Progression from hypertrophic obstructive cardiomyopathy to dilated cardiomyopathy. Apropos of 4 cases].

Four cases of hypertrophic obstructive cardiomyopathy diagnosed on clinical, phonomechanographic, echocardiographic and haemodynamic criteria progressing to dilated cardiomyopathy are reported. This evolution was observed over a number of years (up to 20 years) and was accompanied by a clinical aggravation in all cases with 2 deaths and atrial fibrillation in 3 of the 4 cases. The signs of intraventricular obstruction [systolic murmur, bulge on the carotid pulse tracing, systolic anterior motion of the mitral valve (SAM) and intraventricular pressure gradient] disappeared as the left heart chambers dilated with a reduction in ventricular wall motion and parietal thinning but no change in myocardial mass.