Early Reperfusion in STEMI Influences Transmural Injury Characteristics and Electrocardiographic Manifestations

Abstract

Background: Transmural injury in myocardial infarction (MI) has been regarded to develop Q wave. However, early reperfusion seemes to modify geometry of myocardial fibrosis. Thus, we assesses hypothesis that early reperfusion during acute MI may influence transmural injury patterns and Q wave manifestations on electrocardiogram (ECG). Methods and Results: Total 25 patients with anterior wall ST elevation myocardial infarction (STEMI) (58±12 years, male 84%) were enrolled in this study. All underwent cardiac magnetic resonance (CMR) and ECG 14±10 days after reperfusion therapy with direct percutaneous coronary intervention (PCI) (n=23, 92%) and thrombolytics (n=2, 8%). Transmurality patterns in CMR were divided into two types, diffuse and patchy (mottled or islets). Presence of Q wave and fragmented QRS (fQRS) complex in precordial leads were analyzed. All showed transmural enhancement in CMR (percentage enhanced area: 32±2%). Q wave was observed in 28% and non Q wave group was in 72%. 6 of 7 (86%) patients with Q wave group had diffuse pattern. All patients with non-Q wave showed patchy pattern including mottled (n=12, 67%) and islets (n=6, 33%). 15 of 18 (83%) patients with non-Q wave had fQRS in V1∼V5. Transmurality pattern showed differenent between two groups (diffuse pattern: 86% in Q wave group vs patchy pattern: 100% in non Q wave group; p=0.001). Conclusions: Early reperfusion in STEMI affects transmural injury patterns and Q wave manifestations.