Cardiovascular responses to static and dynamic effort three weeks after myocardial infarction

Left ventricular responses to dynamic and static exercises were compared in 20 patients three weeks after myocardial infarction. Radiocardiography was used to determine the ventricular volumes at rest and during hand grip and bicycle exercise tests. The dynamic exercise increased cardiac output (p less than 0.001), and the end-diastolic volume of the left ventricle increased (p less than 0.005) from the resting value while the ejection fraction decreased (p less than 0.005). Static hand grip exertion did not increase cardiac output or the end-diastolic volume. Decrease of the stroke volume and the ejection fraction (p less than 0.001 both) again reflected pump dysfunction during the afterload stress. Our data revealed that patients with recent myocardial infarction had a range of ventricular responses to dynamic exercise. Poor response in the ejection fraction was noted in anterior infarction and in those patients using digoxin and/or diuretics after infarction. During static exercise, on the other hand, impairment of cardiac performance was constant, irrespective of the site of infarction. Reduction of the ejection fraction was greater during static exercise in the patients receiving digoxin and/or diuretics than in those not taking these drugs.