Background The aim of this study was to evaluate the prognostic significance of the pressure-rate product (PRP) obtained during exercise stress testing and of its change from rest to maximal exercise (dPRP) in a population of survivors of acute myocardial infarction treated with thrombolytic agents. Methods And Results Survivors of acute myocardial infarction (n = 6251) from the GISSI-2 database, who underwent a maximal symptom-limited exercise test with either bicycle ergometer or treadmill, were followed up for 6 months. PRP and dPRP values were dichotomized (≤21,700 and >21,700, ≤11,600 and >11,600, respectively) and analyzed in a multivariate Cox model individually and simultaneously with other ergometric variables. Six-month mortality rate was 0.8% in the high PRP group and 2.0% in the low PRP group. Low PRP was an independent predictor of 6-month mortality rate (relative risk [RR] 1.97, 95% confidence interval [CI] 1.24 to 3.13). Patients with low dPRP had mortality rates higher than patients with high dPRP (2.1% vs 0.8%). At the multivariate analysis, low dPRP showed negative predictive value (RR 1.97, 95% CI 1.23 to 3.16). A further multivariate analysis was performed with PRP and dPRP, also adjusting for low work capacity, abnormal systolic blood pressure response to exercise, and symptomatic-induced ischemia. The results showed that low work capacity, low PRP, and symptomatic exercise-induced ischemia were still significantly associated with higher 6-month mortality rate (P = .04, .02, and .05; RR = 1.68, 1.71, and 1.78 respectively). Conclusions PRP is a predictive index to assess prognosis in survivors of acute myocardial infarction treated with thrombolytic agents able to perform an exercise test after acute myocardial infarction, but its usefulness appears to be limited, considering that these patients were at low risk. (Am Heart J 1999;137:443-52.)