[Echocardiographic triangular patterns of the mitral valve in acute myocardial infarction: a clinical and...

Echocardiographic study was performed on the mitral valve echogram in cases with clinical as well as experimental acute myocardial infarction (AMI). The echocardiograms were recorded in 88 patients with AMI within 7 days from the onset. In 8 patients (9%), and abnormal monophasic triangular diastolic pattern of the mitral valve was observed. Among them, 6 were examined within 12 hours after the onset and the remainder 2 within 24 hours. In all 8, markedly prolonged isovolumic relaxation time (IRT) was present. Mitral valve motion, IRT and peak negative dp/dt of the left ventricle were examined in 5 mongrel dogs following obstruction of the main left coronary artery, one of which was followed up for next 24 hours. Following coronary occlusion, the IRT progressively prolonged from the control value of 20 msec to 130 msec (15 min), 130 msec (30 min), 140 msec (1 hr), 150 msec (6 hr) and 150 msec (24 hr), respectively. The respective values of peak negative dp/dt were 2,000, 800, 840, 840, and 620 mmHg/sec. The possible explanation for these changes was the impaired active relaxation of the left ventricle, resulting in a delayed opening (or at least the lack of usual diastolic opening) of the mitral value, which gave an abortive E-point or a markedly delayed D point. We conclude that the diastolic monophasic triangular pattern of the mitral valve echogram in a reflection of the prolonged left ventricular isovolumic relaxation, and an index of impaired left ventricular diastolic relaxation.