Abstract 14996: Is Early Repolarization Related with Myocardial Scar in Patients with Coronary Artery Disease?

Abstract

Background; Early repolarization(ER), which is characterized by elevation of J-point, is sometimes associated with fatal arrhythmia and sudden cardiac death in patients without structural heart disease. Recent study suggests ER and, in particular, notching in the inferior leads is associated with increased risk of life-threatening ventricular arrhythmias in patients with coronary artery disease(CAD). This study investigated whether ER was related with myocardial scar in patients with CAD. Method: 285 CAD patients with myocardial scar(group 1) were matched for age and sex with 285 CAD without myocardial scar(group 2). ECGs were analyzed for early repolarization, defined as notching or slurring of terminal QRS complex or J-point elevation ≥ 0.1 mV above baseline in at least 2 lateral or inferior leads. Myocardial scar was evaluated using MRI and SPECT. Result; Compare with group 2, patients in group 1 had previous history of MI more frequently (94 [33%] vs. 15 [5%], p<0.001) and lower LV ejection fraction (55 ± 14 vs. 67 ± 8%, p<0.001). In group 1, 109 (38%) patients had ER in any 2 leads, including 78 (27%) patients with ER in inferior leads and 94 (33%) patients with ER and horizontal/descending variant. However, ER was observed in only 35 (12%) patients in group 2, and ER in inferior lead in 32 (11%) patients. ER patterns in any 2 leads (p<0.001) and inferior leads (p<0.001) was more common in group 1 than group 2. During follow up period of 59 ± 36 months, while 13 (4.5%) patients had cardiac events including death, aborted sudden cardiac death or fatal arrhythmia in group 1, none had in group 2 (p<0.001). Among 13 patients with cardiac events, 9 (69%) patients had ER in inferior leads and horizontal/descending ST-segment variant (p=0.03). Patients with ER in inferior leads and horizontal/descending ST variant (n=9) had increased age-, sex- and left ventricular ejection fraction adjusted hazard ratio of cardiac events (relative risk 4.9; 95% confidence interval 1.4-17.8, p=0.02). Conclusion; ER in inferior leads and horizontal/descending ST-segment variant was more frequently observed in CAD patients with myocardial scar and associated with increased risk of adverse cardiac events. These results suggest that ER might be related by myocardial scar in CAD patients.