Contribution of end-diastolic mitral regurgitation to the B-B' step formation on M-mode echocardiography

Although B-B' step is defined as the interruption of closure of the mitral valves with plateaus between A and C points on an M-mode echocardiogram, its implication is still controversial. This study attempted to explore the mechanism of B-B' step formation on an M-mode echocardiogram using pulsed Doppler, color Doppler, and color Doppler M-mode echocardiography. The study included 38 subjects (mean 58.3 yr, SD 15.1 yr), in whom B-B' step was detected on M-mode echocardiography