The effects of hormones on arrhythmias in women.

The reproductive hormones play a significant role in modulating the presentation and behavior of numerous types of arrhythmias. Differences exist between men and women in normal electrophysiology; along with heart rate, the QT interval is a basic parameter that is affected by the presence or absence of certain reproductive hormones. Women have a lower prevalence of atrial fibrillation, yet they have a higher mortality once atrial fibrillation is established. There are clear-cut gender differences in the prevalence of other re-entrant supraventricular tachycardias as well. Women are at lower risk of sudden cardiac death overall, but they have a higher risk of acquired long QT syndrome from antiarrhythmic drugs. It is possible that differences in myocardial repolarization modulated by sex hormones are a major factor in the differential presentation of these arrhythmias in men and women.