Color-coded Doppler Imaging of Systolic Flow Patterns in Hypertrophic Cardiomyopathy

We studied 11 patients with hypertrophic cardiomyopathy by color Doppler echocardiography (Group I: 6 patients with outflow obstruction, and Group II: 5 patients without outflow obstruction) to assess systolic structure and function as observed by cross-sectional echocardiography in relation to the flow dynamics. The structure and function included systolic anterior motion of mitral valve (SAM), midsystolic aortic valve closure (AoC), systolic cavity obliteration and the presence and timing of mitral incompetence. Their occurrence and timing was related to presence of aortic systolic flow and presence of turbulence. While all patients in Group I had SAM and turbulence, none of the patients in Group II had SAM nor turbulence. Early mitral incompetence appearing before SAM and turbulence, occurred in all patients of Group I and in none of Group II. Midsystolic aortic valve closure was only present in Group I and blood flow was unilaterally directed so that only 60% of aortic cross-sectional area showed blood flow. We conclude that mitral incompetence in hypertrophic cardiomyopathy in early systole is common when outflow gradient is present and is independent of mitral incompetence of mid- and late systole. During SAM, turbulence in the subaortic area and mid and late mitral incompetence occurred simultaneously. The midsystolic aortic valve closure was related to the unilaterally directed blood flow through the aortic cross-sectional area.