Differences between ventricular repolarization in men and women: description, mechanism and implications

Area of Science:

• Cardiology
• Electrophysiology
• Endocrinology

Background:

• Ventricular repolarization patterns exhibit significant sex-based differences.
• Women have a higher incidence of torsade de pointes (tdp) and QT-interval prolongation with certain antiarrhythmic drugs compared to men.
• These differences emerge around puberty and are influenced by sex hormones.

Purpose of the Study:

• To review and discuss the morphological, mechanistic, and clinical differences in ventricular repolarization between males and females.
• To explore the role of hormonal influences, particularly testosterone, on these sex-based repolarization patterns.
• To consider the implications of these differences for the risk of cardiac arrhythmias like tdp.

Main Methods:

• Review of existing literature on sex differences in ventricular repolarization.
• Analysis of morphological characteristics of repolarization patterns in males and females.
• Examination of hormonal effects on repolarization, including studies in animal models (rabbits).

Main Results:

• A distinct male repolarization pattern emerges at puberty, characterized by specific ECG waveform features and influenced by testosterone levels.
• This male pattern's prevalence decreases with age in men, while the female pattern remains consistent across age groups.
• Females exhibit greater divergence in L-type calcium currents and lower densities of repolarizing currents (Kr, Ks) compared to males.

Conclusions:

• Significant sex-based differences exist in ventricular repolarization morphology and underlying ionic mechanisms.
• Hormonal factors, especially testosterone, play a crucial role in establishing and modulating these sex-specific repolarization patterns.
• The clinical significance of these repolarization disparities, particularly concerning arrhythmia risk (tdp), requires further investigation.