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Gender differences in autonomic modulation of ventricular repolarization in humans
Mikiko Nakagawa1, Tatsuhiko Ooie, Baiqing Ou
1Department of Cardiovascular Science, Division of Laboratory Medicine, Oita University , School of Medicine, Oita, Japan. mikinak@oita-med.ac.jp
Journal of Cardiovascular Electrophysiology
|April 9, 2005
Summary
Women exhibit a more pronounced dynamic electrophysiological response to sympathetic stimulation and autonomic blockade compared to men. This gender difference in ventricular repolarization may contribute to women's increased susceptibility to arrhythmias.
Area of Science:
- Cardiology
- Electrophysiology
- Human Physiology
Background:
- Ventricular arrhythmias and Torsades de Pointes are more prevalent in women.
- The role of sympathetic tone in arrhythmia vulnerability is established, but gender differences in dynamic electrophysiological responses are less understood.
Purpose of the Study:
- To investigate gender differences in the dynamic electrophysiological response of ventricular repolarization to beta-adrenergic stimulation and autonomic blockade in humans.
Main Methods:
- Twelve-lead ECGs were recorded in 24 healthy volunteers (12 men, 12 women) during isoproterenol infusion and autonomic blockade (propranolol and atropine).
- QT and corrected QT (QTc) intervals were measured at baseline and varying heart rates (75, 100, 120 bpm).
Main Results:
- T-wave morphology changes during isoproterenol infusion were more frequent in women.
- QTc interval prolongation during isoproterenol administration was significantly greater in women than in men.
- Intrinsic QTc intervals were longer in women than men under autonomic blockade.
Conclusions:
- Sympathetic stimulation and autonomic blockade more significantly impact ventricular repolarization dynamics in women compared to men.
- These pronounced gender-specific electrophysiological responses may explain the higher susceptibility of women to certain cardiac arrhythmias.