Abstract

Background: Early repolarization (ER) has been linked to the risk of sudden cardiac death (SCD) in the general population, although controversy remains regarding risks across various subgroups.

Objective: The purpose of this study was to investigate whether age and sex influence the prognostic significance of ER.

Methods: We evaluated the 12-lead electrocardiograms of 6631 Finnish general population subjects age ≥30 years (mean age 50.1 ± 13.9 years; 44.5% men) for the presence of ER (J-point elevation ≥0.1 mV in ≥2 inferior/lateral leads) and followed them for 24.4 ± 10.3 years. We analyzed the association between ER and the risk of SCD, cardiac death, and all-cause mortality in subgroups according to age (<50 or ≥50 years) and sex.

Results: ER was present in 367 of the 3305 subjects age <50 years and in 426 of 3326 subjects ≥50 years. ER was not associated with any of the endpoints in the entire study population. After adjusting for clinical factors, ER was associated with SCD (hazard ratio [HR] 1.88; 95% confidence interval [CI] 1.16–3.07) in subjects <50 but not in older subjects (interaction between ER and age group, P = .048). In the younger subgroup, women with ER had a high risk of SCD (HR 4.11; 95% CI 1.41–12.03), whereas among men ER was not associated with SCD. Finally, ER was not associated with cardiac mortality or all-cause mortality in either age group.

Conclusion: ER is associated with SCD in subjects younger than 50 years, particularly in women, but not in subjects 50 years and older.