The effect of recanalization of the occluded coronary artery in acute myocardial infarction on left ventricular function

In 20 patients with acute myocardial infarction a left ventriculogram was obtained within 6 h after the onset of chest pain and again during a follow-up study, 2–3 weeks later. In 17 patients the infarct-related vessel (IR V) could be recanalized with selective intracoronary infusion of a thrombolytic agent and was still patent during the second study. In three other cases the IR V was already patent during the first angiogram and remained so at the time of the follow-up study. The ejection fraction of these 20 patients increased from 52 to 56% (P < 0.02). In eight other patients the infarct-related artery could not be recanalized or was reoccluded at the time of the control study. The ejection fraction of these patients with unsuccessful recanalization decreased from 49 to 37% (P<0.001). Analysis of regional function in eight patients with anterior infarction and seven patients with inferior infarction, all with a successful recanalization and persistent patency of the infarct-related vessels, suggests that improvement of global ejection fraction is only partially due to improvement of regional pump function in the reperfused 'infarct zone' but may also be caused by enhancement of regional function in other wall regions or by changes in afterload.