Aims: An association has been described between death from arrhythmia and early repolarization, an electrocardiogram pattern characterized by elevation of the QRS-ST junction (J-point). Little is known about this relationship in non-white populations. This study examines the relationship between J-point elevation (JPE) and sudden cardiac death (SCD) and whether this relationship differs by race or sex.
Methods and results: A total of 15 141 middle-aged subjects from the prospective, population-based Atherosclerosis Risk in Communities (ARIC) study were included in this analysis. The primary endpoint was physician-adjudicated SCD occurring from baseline (1987-1989) through December 2002, secondary endpoints were fatal and non-fatal coronary events and all-cause mortality occurring through December 2007. J-point elevation was defined as J-point amplitude ≥ 0.1 mV. Pre-specified subgroup analyses by sex and race were conducted. J-point elevation in any lead was present in 1866 subjects (12.3%). After adjustment for demographic, clinical, lifestyle, and laboratory variables, JPE was not significantly related to SCD in the overall sample [adjusted hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.87-1.75]. However, significant interactions were present between race and JPE (P = 0.006) and between sex and JPE (P = 0.020). J-point elevation was significantly predictive of SCD in whites (adjusted HR, 2.03; 95% CI, 1.28-3.21) and in females (adjusted HR, 2.54; 95% CI, 1.34-4.82).
Conclusion: Our results suggest that JPE is associated with an increased risk of SCD in whites and in females, but not in blacks or males. Further studies are needed to clarify which subgroups of individuals with JPE are at increased risk for adverse cardiac events.