The role of exercise radionuclide angiocardiography in predicting future cardiac events in patients with acute myocardial infarction.

Abstract

Left ventricular ejection fraction (LVEF) during exercise radionuclide angiocardiography is a useful prognostic index for patients with acute myocardial infarction (AMI). However, most previous studies were performed before reperfusion therapies (i.e., thrombolysis and coronary angioplasty) were widely used. Therefore, because reperfusion therapy has become a standard therapeutic option, we reexamined the prognostic value of rest LVEF and exercise LVEF determined by radionuclide angiocardiography in patients with AMI at the time of hospital discharge. The retrospective analysis included 419 consecutive patients with AMI who underwent ergometric stress radionuclide angiocardiography before hospital discharge, 44 +/- 14 d after the onset of AMI. During a mean follow-up of 4.6 y, cardiac events occurred in 101 (24.1%) patients. Cardiac events included recurrent MI (33 patients, 7.9%), unstable angina (49 patients, 11.7%), congestive heart failure (16 patients, 3.8%), and ventricular tachycardia (3 patients, 0.7%). The LVEF at peak exercise was significantly lower in the group with cardiac events (P = 0.0140). However, no significant difference was observed in the rest LVEF between patients with and without cardiac events. On the basis of multivariate analysis using a Cox proportional hazards model, only peak LVEF (P = 0.0246) was found to be an independent predictor of cardiac events. In the patient subsets with a peak LVEF >50% or <50%, the event-free rate was 81.0% versus 62.4% (P = 0.0007), respectively. Regardless of the presence or absence of reperfusion therapy, the lower peak LVEF was associated with a decrease in the event-free survival rate. In the current reperfusion era, the lower peak LVEF as measured by radionuclide angiocardiography at the time of discharge is a useful predictor of subsequent cardiac events in patients with AMI.