Abstract 15958: Early Repolarization and Testosterone Levels
Background. There is a significant age- and gender dependence in the prevalence of early repolarization (ER) in the inferior/lateral leads of a standard 12-lead ECG with male predominance and a high prevalence in young subjects. Recently, a genome-wide association study of ER suggested an associated locus near KCND3, encoding for a subunit of Ito channel, which has been described to be highly influenced by testosterone. We tested the hypothesis that testosterone levels may be associated with the ER ECG phenotype.
Methods and results. We analyzed the ECGs from the Health 2000 study population (n= 6,306; mean age 53 ± 15yrs) to identify the prevalence of ER and determined serum testosterone levels from all male subjects. We excluded all subjects with bundle branch blocks from the ECG analysis (n= 144). The prevalence of infero-lateral ER was 3.0% (inferior 0.7%, lateral 1.9%, both 0.4%). Males had significantly higher prevalence of ER compared to females (5.1% v. 1.3%, p< 0.001, respectively). Testosterone levels, which were analyzed from 2,755 male subjects (mean age 51 ± 14yrs, mean level 15.84 ± 6.08nmol/l), were significantly higher in subjects with the ER compared to subjects without the ER ECG phenotype (17.82 ± 6.24nmol/l v. 15.73 ± 6.05nmol/l, age adjusted p= 0.002). Higher testosterone levels were strongly associated with lateral (p= 0.015) and infero-lateral ER (p= 0.001). In a subgroup analysis, testosterone was strongly associated with ER followed by rapidly ascending ST-segment morphology (p= 0.001), but a weaker association was observed with ER+horizontal/downsloping ST-segment (p= 0.035).
Conclusion. Higher testosterone levels are associated with the ER patterns; more specifically with lateral ER and ER followed by ascending ST-segment. Testosterone influence on Ito channel might play an important role in the electrophysiological background of ER.
- © 2012 by American Heart Association, Inc.