Presence of early repolarization on admission electrocardiography is associated with long-term mortality and MACE in patients with STEMI undergoing primary percutaneous intervention

Abstract

Background: Early repolarization (ER) is associated with increased risk of sudden cardiac death and ventricular fibrillation (VF) in patients with/without structural heart disease. In this trial we examined the short- and long-term prognostic value of ER on admission electrocardiogram (ECG) in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

Method: Consecutive 521 patients with acute STEMI who underwent primary PCI were enrolled prospectively. Twelve-lead ECGs obtained during the initial diagnosis were scanned and stored digitally. The leads showing the typical ST segment elevation due to the acute infarction were excluded and the remaining ECG leads were included in the analysis for the presence of ER.

Results: The study group included 61 STEMI patients (55 male; mean age 57.6±12.6 years) with ER and 460 STEMI patients (378 male; mean age 57.1±12.5) without ER on ECG. In the ER group, 14 patients (22.9%) had notching, 10 patients (16.4%) had slurring, and 37 patients (60.7%) had only J-point elevation. When analyzing regional leads, ER was observed mostly in inferior leads (n=40, 65.6%). During the hospitalization period, ventricular tachycardia or VF occurred more frequently in the ER group (19.6% vs. 10.9%; p=0.04) and 6 patients (6.9%) from the ER group and 14 patients (3%) from the control group died (p=0.01). During a follow-up period of 21.1±10.2 months, mortality was significantly higher in the ER group (12.7% vs. 4.2%; p=0.01). When total mortality rates were considered, highest mortality was observed in patients with notching pattern (5/14 subjects; 35.7%) when compared to patients with slurring (3/10 subjects; 30%), patients with only J-point elevation patterns (5/37subjects; 13.5%) and the control group (33/460 subjects; 7.1%). Presence of notching and slurring pattern on admission ECG was found as independent predictors of long-term mortality; whereas presence of only J-point elevation was not.

Conclusion: Presence of ER pattern in admission ECG in patients with STEMI is associated with both in-hospital and long-term mortality.

Keywords: Arrhythmia; Early repolarization; Mortality; ST segment elevation myocardial infarction.