Abstract 2561: Prevalence and Prognostic Significance of Early Repolarization Pattern on 12-lead Electrocardiogram in a Middle-Aged Finnish Population
Background. Early repolarization, characterized by prominent J-wave in infero-lateral leads of a standard 12-lead electrocardiogram (ECG), has been recently associated with vulnerability to malignant cardiac arrhythmias in anecdotal case reports, although it has been considered to be an innocent variant for decades. We studied the prevalence and prognostic significance of J-point elevation in infero-lateral leads in a large community-based general population.
Methods. We evaluated 12-lead ECGs of 10 864 Finnish middle-aged subjects from general population (52% males, mean age 44±8.5 years). The mean follow up period was 30±11 years. Primary end points were all cause and cardiac mortality. Early repolarization was defined as notched or slurred J-point elevation of at least 0,1mV from baseline in at least two consecutive inferior or lateral leads. Relative risks (RR) were adjusted for age, sex, body mass index, smoking, systolic blood pressure, heart rate and ECG signs of left ventricular hypertrophy (LVH).
Results. The prevalence of early repolarization pattern was 5,8% (n=630, 64% males), including 3,4% in inferior and 2,3% in lateral leads. Subjects with early repolarization pattern had a higher risk for all cause (adjusted RR 1.14; 95% CI 1.03–1.26, p=0.01) and cardiac mortality (RR 1.36; 95% CI 1.08 –1.72, p=0.01) than those without early repolarization. Subjects with a J-point elevation >0,2mV from baseline (n=67) had even a higher risk for all cause (RR 1.41; 95% CI 1.06 –1.87, p=0.006) and cardiac mortality (RR 2.50; 95% CI 1.50 – 4.17, p=0.002). J-point elevation >0,2mV (n=36) in inferior leads was associated with a higher risk for cardiac mortality (RR 3.49; 95% CI 1.92– 6.34, p<0.001) than prolonged QTc interval (adjusted RR 1.28, 95% CI 1.02–1.61, p=0.04), ECG signs of LVH (RR 1.22, 95% CI 1.06 –1.40, p=0.005), or prolonged QRS duration (>120 ms) (RR 2.09, 95% CI 0.86 –5.05, p=0.15).
Conclusion. The presence of J-point elevation in infero-lateral leads of a standard 12-lead ECG is not a rare finding in general middle-aged population, and it is associated with increased mortality. Marked J-point elevation in inferior leads is a stronger predictor of cardiac mortality than the other common ECG risk markers.