Effect on outcome of the presence or absence of chest pain at initiation of recombinant tissue plasminogen activator therapy in acute myocardial infarction

To ascertain whether the outcome of patients with suspected myocardial infarction differs when chest pain is still present at initiation of thrombolytic therapy, participants in the Thrombolysis in Myocardial Infarction Phase 11 study, all of whom presented within 4 hours of symptoms onset, were retrospectively divided into 2 groups: (1) those with chest pain present at onset of intravenous thrombolysis, n = 3,000; and (2) those who were free of chest pain on beginning intravenous thrombolytic therapy, n = 337. Patients free of chest pain were older (58 vs 57 years, p = 0.01), more often women (23 vs 17%, p = 0.01), had fewer electrocardiographic leads with ST elevation (3.8 vs 4.1, p