Background: Although sex-dependent differences in cardiac repolarization have been known for many years, few attempts have been carried out to define the individual contribution of each electrocardiographic (ECG) repolarization variable to the sex-dependent pattern.
Method and results: We analyzed several ECG repolarization variables that reflect both the duration and the rate of repolarization in 500 normal healthy subjects between the ages of 20 and 80 years (250 men and 250 women) and distributed into 5 groups according to age. Cardiac repolarization, measured in the precordial lead exhibiting the highest T-wave amplitude, was found to be shorter and faster in normal men compared with normal women (P <.001). The parameters with the highest individual weight in determining these sex differences were the J point and the ST angle, as indicated by nonlinear (logistic) multivariate regression analysis.
Conclusion: We conclude that changes in the duration and rate of early repolarization are determinants for these sex-dependent ECG pattern differences.