Dynamic and static exercise haemodynamics after acute myocardial infarction.

The cardiovascular responses to dynamic and static exercises were studied in 20 patients by exercise tests performed at 3 weeks and 12 weeks after acute myocardial infarction. The left ventricular size and volume output were determined by radiocardiography. The mean cardiac output during dynamic exercise at the second study was 24% (p less than 0.05) higher than at the first study, mainly because the peak heart rate was 19% (p less than 0.05) higher. The left ventricular end-diastolic volume or its response to ergometric exercise did not change during the 3-month follow-up and the ejection fraction and stroke volume showed minor changes only. During static exercise a 3% better increase in cardiac output was seen from 3 to 12 weeks, without any improvement in ejection fraction. At the 12-week study the changes in cardiac performance during ergometric exercise were not related to the site of infarction or drug therapy. During static exercise slight improvement of cardiac output, stroke volume and ejection fraction responses were seen in the course of time, but only in the patients with inferior infarction and in those not receiving digoxin and/or diuretics. The mean cardiac output during dynamic exercise improved by one-quarter, mainly due to a higher peak heart rate, in the course of the 3-month follow-up after myocardial infarction. Otherwise, haemodynamic variables during dynamic or static exercises within 3 months showed insignificant sequential changes only.