Echocardiography in the diagnosis of hypertrophic obstructive cardiomyopathy

The role of echocardiography in the diagnosis of hypertrophic obstructive cardiomyopathy is reviewed. Salient features include a narrowed left ventricular outflow space, the increased thickness of the interventricular septum and the systolic anterior motion of the anterior mitral leaflet. The last may be present at rest, or it may be provoked with appropriate maneuvers. When all three features are demonstrated, a diagnosis of hypertrophic obstructive cardiomyopathy can be made with confidence. In the absence of resting or provocable systolic anterior motion, a diagnosis of nonobstructive cardiomyopathy may be entertained. An additional important echocardiographic feature of hypertrophic obstructive cardiomyopathy consists of an interventricular septal to posterior wall ratio in excess of 1.5, suggesting the asymmetric distribution of hypertrophy. Inert interventricular septum, aortic valve preclosure and a reduced diastolic slope of the anterior mitral leaflet are frequently present, but not specific for the condition. When hypertrophic obstructive cardiomyopathy is associated with other unrelated diseases, the index of suspicion may be raised even in the absence of all the “classic” echo signs.