ST peak during primary percutaneous coronary intervention predicts final infarct size, left ventricular function, and clinical outcome

Background and PurposeOne third of patients treated with primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction develop a secondary increase in electrocardiographic ST segment (ST peak) during reperfusion. The purpose was to determine the clinical importance of ST peak during primary PCI.MethodsA total of 363 patients with ST-elevation myocardial infarction were stratified to no ST peak or ST peak. Final infarct size and ejection fraction (EF) were assessed by cardiovascular magnetic resonance.ResultsPatients with ST peak had a larger infarct size (14% vs 10%; P = .003) and lower EF (53% vs 57%; P = .022). Rates of cardiac mortality (8% vs 3%; P = .047) and cardiac events (cardiac mortality and admission for heart failure; 19% vs 10%; P = .018) were higher among patients with ST peak, but not all-cause mortality (8% vs 5%; P = .46). In a multivariable Cox regression analysis, ST peak remained significantly associated with cardiac events (adjusted hazard ratio, 2.03 [1.08-3.82]).ConclusionST peak during primary PCI is related to larger final infarct size, a reduced EF, and adverse cardiac clinical outcome.