the effect of mitral valve closure on left ventricular filling time and its relation to the onset of systole were assessed from mitral valve echocardiograms and simultaneous apex cardiograms in 21 normal subjects , 11 patients with left bundle branch block , and 19 patients with vdd pacemakers programmed for atrioventricular intervals of 50 , 150 , and 250 ms .
C0225897
left ventricular
C0026264
mitral valve