[Thrombolysis and acute myocardial infarction. Reduced residual ischemia in first acute myocardial infarction].

In order to assess the effect of thrombolysis on residual myocardial ischaemia, we prospectively performed maximal exercise testing and ambulatory ST-segment monitoring in a consecutive series of 123 men recovering from a first acute myocardial infarction (AMI). Seventy-four patients fulfilled our criteria for thrombolysis, but only 35 patients received thrombolytic agents, whereas 39 were conservatively treated (controls). In 49 patients thrombolytic therapy was not indicated. Thrombolysis resulted in a non-significant reduction in the prevalence of exercise-induced ST-segment depression: 43% in reperfused patients versus 62% in controls. During 36-hour ambulatory ST-segment monitoring, however, the duration of myocardial ischaemia was significantly reduced in thrombolyzed patients: 322 minutes versus 1144 minutes in controls (p < 0.05). Exercise testing revealed a higher maximal work capacity in thrombolyzed patients compared with controls: 160 +/- 41 versus 139 +/- 34 W (p < 0.02). No difference was found in left ventricular ejection fraction between the two subgroups. We conclude, that thrombolysis given for a first AMI reduces residual myocardial ischaemia. The reduced ischaemic burden is assumed to be the pathophysiologic mechanism underlying the also observed improvement in exercise tolerance.