Value of systolic time intervals in the estimation of heart failure secondary to acute myocardial infarction.

Serial measurements of left ventricular systolic time intervals (STI) were carried out in 44 patients with acute myocardial infarction (AMI) in the first 5 days after onset, by indirect methods. The patients with heart failure showed significant decreases of ejection time (ET) (p less than 0.001) and of the ejection time index (p less than 0.005) and increases of Wiessler's ratio (PEP/ET) (p less than 0.001). The pre-ejection period (PEP), the isovolumetric contraction time and the total electromechanical systole were unsignificantly changed. Ejection time was shorter than 250 msec in the patients with acute pulmonary edema or congestive heart failure, in most of the patients with flutter or atrial fibrillation and in 16 of the 17 patients who died. Ejection time may have a prognostic significance and may be useful in the early detection of heart failure in AMI. The changes of STI after administration of lanatosid C show the positive inotropic effect of this drug in patients with AMI.