Effect of Prodromal Angina Pectoris on the Infarct Progression in Patients With First ST-Elevation Acute Myocardial Infarction

Background: Prodromal angina pectoris (AP) has a cardioprotective effect by the mechanism of ischemic preconditioning, and the QRS score on the admission electrocardiogram (ECG) reflects myocardial damage at presentation. This study was undertaken to investigate the effect of prodromal AP on infarct progression after the onset of acute myocardial infarction (AMI). Methods and Results: The study group comprised 291 patients with a first ST-elevation AMI who underwent coronary angiography within 24 h of symptom onset. QRS score was calculated from the admission ECG. Patients were divided into 3 groups according to elapsed time from onset of AMI to angiography: early group (