SILENT VERSUS SYMPTOMATIC DIPYRIDAMOLE-INDUCED ISCHEMIA AFTER MYOCARDIAL-INFARCTION - CLINICAL AND PROGNOSTIC-SIGNIFICANCE

The prevalence and prognostic significance of silent myocardial ischem ia were prospectively assessed in 217 patients (mean age 57 +/- 9 year s, 83% male) recovering from a first uncomplicated acute myocardial in farction and undergoing a dipyridamole echocardiography test before ho spital discharge. Clinical, angiographic, exercise electrocardiographi c (ECG) and dipyridamole echocardiographic variables were also examine d. Of the 217 patients, 89 had no echocardiographically proved dyssyne rgy after dipyridamole, whereas 128 had dipyridamole-induced wall moti on abnormalities that were silent in 94 (Group I) and symptomatic in 3 4 (Group II). There was no intergroup difference with respect to dipyr idamole time (i.e., the time from onset of the test to frank dyssynerg y: 7 +/- 3 vs. 8 +/- 3 min; p = NS); prevalence of inferior myocardial infarction (69% vs. 71%; p = NS); ischemic ECG changes during the tes t (83% vs. 71%; p = NS); diabetes (8.5% vs. 6%; p = NS); ongoing medic al therapy; multivessel disease (57% vs. 56%; p = NS); and baseline le ft ventricular ejection fraction (57 +/- 13% vs. 57 +/- 10%; p = NS). There was also no significant difference between Group I and Group II with respect to wall motion score index at peak dipyridamole effect (1 .77 +/- 0.39 vs. 1.78 +/- 0.36; p = NS). Patients were followed up for 24 +/- 4 and 25 +/- 5 months, respectively (p = NS). Life table analy sis revealed no difference in unstable angina, reinfarction and death between the two groups. A Cox survival analysis identified a positive echocardiogram after dipyridamole administration as the best predictor of cardiac events (chi-square = 9.1; p < 0.003), whereas dipyridamole -induced chest pain showed no independent predictive value (chi-square = 2.7; p = NS). Thus, patients with silent ischemia and symptomatic i schemia had comparable 1) severity of dipyridamole-induced ischemia (a s assessed by dipyridamole time and extent of wall motion abnormalitie s), 2) extent of angiographic coronary artery disease, and 3) incidenc e of critical cardiac events.