It has been suggested that mitral regurgitation(MR) of hypertrophic cardiomyopathy is associated with left ventricular outlet pressure gradient, systolic anterior motion of mitral leaflet, abnormal coaptation of mitral valve, malalignment of papillary muscle and elongation of mitral leaflet. To investigate the relation between the degree of MR and the several causing factors, we reviewed 35 patients with hypertrophic cardiomyopathy.

35 patients with hypertrophic cardiomyopathy were classified into a group I(24 patients) without mitral regurgitation and with grade 1 MR or a group II(11 patients) with grade 2 and grade 3 MR. Measurement of mitral leaflet was performed on 2-D echocardiography. Distance between interventricular septum and systolic anterior motion(SAM) of the mitral leaflet was measured on M-mode echocardiography.

1) Mitral regurgitation was observed in 22 patients(63%) among 35 patient. 2) Left ventricular outflow pressure gradient was 11±10mmHg in group I, 79±68mmHg in group II(p<0.05). Interventricular septum-SAM distance was 1.0±0.3cm in group I, 0.3±0.5cm in group II. 3) Anterior mitral leaflet length was 2.76±0.51cm in group V, 2.89±0.34cm in group II and posterior mitral leaflet length was 1.71±0.43cm in group I, 1.80±0.29cm in group II(p>0.05). 4) Mitral annulus circumference was 8.57±1.13cm in group I, and 8.58±0.92cm in group II(p>0.05).

There was no correlation between the degree of mitral regurgitation and mitral leaflet length or mitral annulus circumference but, left ventricular outflow pressure gradient and interventricular septum-SAM distance were good correlated with degree of mitral regurgitation.