Early repolarization associated with ventricular arrhythmias in patients with chronic coronary artery disease

Abstract

Background: Early repolarization, indicated on the standard 12-lead ECG, has recently been associated with idiopathic ventricular fibrillation in patients without structural heart disease. It is unknown whether there is an association between early repolarization and ventricular arrhythmias in the coronary artery disease (CAD) population.

Methods and results: Patients with CAD with implantable cardioverter-defibrillators in the healed phase of myocardial infarction were analyzed. In a case-control design, 60 patients who had ventricular arrhythmic events were matched for age and sex with 60 control subjects. ECGs were analyzed for early repolarization, defined as notching or slurring morphology of the terminal QRS complex or J-point elevation ≥0.1 mV above baseline in at least 2 lateral or inferior leads. Results were adjusted for left ventricular ejection fraction. Overall, early repolarization in 2 or more leads was more common in cases than control subjects (32% versus 8%, P=0.005). Early repolarization was noted more commonly in inferior leads (23% versus 8%, P=0.03), and a trend was noted in leads V(4) through V(6) (12% versus 3%, P=0.11). Early repolarization was uncommon in leads I and aVL in cases and control subjects (3% versus 0%). Notching was more common in cases than control subjects (28% versus 7%, P=0.008). Slurring and J-point elevation were not associated with ventricular arrhythmias.

Conclusions: Early repolarization and, in particular, notching in the inferior leads is associated with increased risk of life-threatening ventricular arrhythmias in patients with CAD, even after adjustment for left ventricular ejection fraction. Our findings suggest early repolarization, and a notching morphology should be considered in a risk prediction model for arrhythmias in patients with CAD.