Resolution of ST-segment elevation after thrombolytic therapy in elderly patients with acute myocardial infarction.

We examined the resolution of ST-segment elevation after thrombolytic therapy in elderly versus younger patients with acute myocardial infarction. Electrocardiograms were recorded before, on completion of, and on day 1 and day 2 post-thrombolytic therapy (streptokinase or tissue thromboplastin activator) in 36 patients older than 65 years and 36 patients younger than 65 years. There was no significant different in the pre-thrombolytic ST-segment elevation per lead in both elderly and younger patients (3.7 +/- 0.7 versus 3.5 +/- 0.8 mm; P = NS). On completion of thrombolytic therapy, both groups demonstrated resolution of ST-segment elevation and, although the ST-segment elevation per lead was higher in elderly patients (3.0 +/- 0.9 versus 2.5 +/- 0.9 mm; P = 0.008), the percentage resolution per lead was not significantly different (19% versus 29%; P = NS). On day 1 post-thrombolytic therapy, there was further resolution of ST-segment elevation in both groups, but at this point, the percentage resolution per lead was significantly less in the elderly than in the younger patients (51% versus 66%; P = 0.03), and the ST-segment elevation per lead remained higher in elderly patients (1.8 +/- 1.0 versus 1.2 +/- 0.6 mm; P = 0.0009). On day 2 post-thrombolytic therapy, although there was further resolution of ST-segment elevation in both groups, the percentage resolution per lead remained significantly less (68% versus 80%; P = 0.05) and ST-segment elevation per lead remained significantly higher in elderly patients (1.2 +/- 0.7 versus 0.7 +/- 0.4 mm; P = 0.0002). Resolution of ST-segment elevation after thrombolytic therapy was less marked in elderly patients, indicating a reduced response to thrombolytic therapy in this patient population.