[Study of systolic time by external phonomechanocardiography in myocardial infarction. 1. Value of systolic times and their course during the 1st 3 weeks].

A phonomechanographic study was carried out on 38 patients with recent myocardial infarction both during the initial phase of necrosis (between the 5th and 7th day) and at the end of the third week. The parameters studied were electromechanical systole (QB2), systolic ejection time corrected for heart rate (CET), the OBl interval, isometric contraction (IC), the pre-ejection periode (PEP), and the haemodynamic coefficient (PEP/ET). The results were compared with the values found in a similar control series. A tendency towards lengthening of the pre-ejection times and shortening of the corrected ejection time was noted. These changes were significant for the second measurement of CET, and for the ratio PEP/ET during the initial phase and on second measurement. The pre-ejection times were generally increased more markedly in the group of patients with left ventricular failure; the ejection time was also markedly shorter in this group, and the haemodynamic coefficient was larger. There was a tendency for the various measurements studied to return to normal by the third week.