Early repolarization on the electrocardiogram: no longer so benign!

Reports have surfaced over the past couple of years on the early repolarization pattern, traditionally considered benign, in patients with idiopathic ventricular fibrillation, and the pattern is now considered a marker of risk for sudden cardiac death. [1] [2] [3]

NEJM now has this new report:

Results The early-repolarization pattern of 0.1 mV or more was present in 630 subjects (5.8%): 384 (3.5%) in inferior leads and 262 (2.4%) in lateral leads, with elevations in both leads in 16 subjects (0.1%). J-point elevation of at least 0.1 mV in inferior leads was associated with an increased risk of death from cardiac causes (adjusted relative risk, 1.28; 95% confidence interval [CI], 1.04 to 1.59; P=0.03); 36 subjects (0.3%) with J-point elevation of more than 0.2 mV in inferior leads had a markedly elevated risk of death from cardiac causes (adjusted relative risk, 2.98; 95% CI, 1.85 to 4.92; P less than 0.001) and from arrhythmia (adjusted relative risk, 2.92; 95% CI, 1.45 to 5.89; P=0.01). Other electrocardiographic risk markers, such as a prolonged QT interval corrected for heart rate (P=0.03) and left ventricular hypertrophy (P=0.004), were weaker predictors of the primary end point.

Conclusions An early-repolarization pattern in the inferior leads of a standard electrocardiogram is associated with an increased risk of death from cardiac causes in middle-aged subjects.

Early repolarization associated with SCD is usually present in the inferior leads but not exclusively so. Two patients in the JACC series later turned out to have Brugada syndrome. The full text of these references is worth reading, as they contain illustrations of the pattern.