CYCLICAL VARIATION IN PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA IN WOMEN

Background Paroxysmal supraventricular tachycardia (SVT) in premenopau sal women is often judged to be related to anxiety, and may be associa ted with the menstrual cycle. The aim of this study was to determine w hether a cyclical variation of episodes of SVT exists and to correlate such variation with cyclical variation in plasma ovarian hormones. Me thods 26 women (mean age 36 [SD 8]) years; with paroxysmal SVT were sc reened; those with regular menses who experienced at least three episo des of paroxysmal SVT in two consecutive 48-hour ambulatory ECG record ings were included. 13 patients (aged 32 [6] years) met these criteria . Patients underwent 48-hour ambulatory ECG monitoring and determinati on of plasma concentrations of oestradiol-17 beta and progesterone on day 7, 14, 21, and 28 of their menstrual cycle. Findings An increase i n the number and duration of episodes of paroxysmal SVT was observed o n day 28 as compared to day 7 of the menstrual cycle. A significant po sitive correlation was found between plasma progesterone and number of episodes and duration of SVT (5.6 [2.2] ng/mL; r=0.83, p=0.0004; and r=0.82, p=0.0005), while a significant inverse correlation was found b etween plasma oestradiol-17 beta and number of episodes and duration o f SVT (155 [22] pg/mL; r=-0.89, p<0.0001; acid r=-0.81, p=0.0007). Int erpretation Women with paroxysmal SVT and normal menses exhibit a cycl ical Variation in the occurrence of the arrhythmia with their menstrua l cycle. There is a close correlation between the episodes of paroxysm al SVT and the plasma concentrations of ovarian hormones. These data s uggest that changes in plasma levels of ovarian hormones (and their in teraction) may be of importance in determining episodes of arrhythmia in such patients. The mechanisms of these effects are unknown.