Early repolarization, long thought to be benign, is associated with an increased risk of death from cardiac causes, according to a new study presented here at the AHA and published online in the New England Journal of Medicine. Finnish investigators examined the ECGs of 1,864 middle-aged people to assess the prognostic significance over 30 years of early repolarization (defined as an elevation of the QRS-ST junction– J point– in leads other than V1 through V3).

Overall, 5,8% of the population were found to have early repolarization, conferring a 28% increased risk of death from cardiac causes (p=0.03). Among the 36 patients with J-point elevation of more than 0.2 mV in inferior leads had a three-fold increase in the risk of death from cardiac causes and from arrhythmia.

Increased risk was observed more in subjects who had early repolarization in the inferior leads compared to the lateral leads. The investigators noted that the mechanism by which early polarization leads to increased risk is unknown, but observed that the continued presence of the pattern on repeated ECGs suggest that it is a “permanent electrophysiological disorder.” The survival curves began to separate after 15 years and continued to separate from then on.