Early repolarization pattern is associated with ventricular fibrillation in patients with acute myocardial infarction

BACKGROUND For years early repolarization (ER) has been considered as a benign electrocardiographic finding. However, recent reports show that ER is associated with a higher incidence of ventricular fibrillation (VF) and sudden cardiac death in patients without structural heart disease. Sporadic case studies have pointed out that ER might be related to an adverse outcome in patients with stable coronary artery disease. OBJECTIVE To evaluate the incidence of ER in patients with acute myocardial infarction complicated by VF. METHODS The study population consisted of 60 patients (80% men; mean age 61.8 +/- 13.1 years) with acute myocardial infarction. Thirty consecutive patients (80% men; mean age 63.3 +/- 12 years) admitted to our hospital had documented VF during myocardial infarction and were successfully resuscitated before hospital admission. A matched control group consisted of 30 patients (80% men; mean age 60.2 +/- 14.2 years) with myocardial infarction without ventricular tachyarrhythmias. Twelve-lead electrocardiograms were analyzed for ER defined as J-point elevation >= 0.1 mV and "notching" and "slurring" of the terminal part of the QRS complex in at least 2 lateral or inferior leads. RESULTS The ER pattern was observed in 18 of the 60 patients with acute myocardial infarction. Mean elevation of the J point was 0.151 +/- 0.46 mV. Notching of the J wave was observed in 14 of the 18 patients and slurring in 4 of the 18 patients. ER was more common in patients with myocardial infarction complicated by VF than in patients with myocardial infarction without ventricular tachyarrhythmias (47% vs 13%; P = .005). There have been no statistical differences in the distribution of ER in the 12-lead electrocardiogram (inferior 39% vs lateral 33% vs inferolateral 28%; P > .05). CONCLUSION Early repolarization pattern seems to be associated with ventricular tachyarrhythmias in the setting of acute myocardial infarction.