Background and Objectives: The effects of gender differences on cardiac
parameters have been well-established. In this study, we aimed to
evaluate the possible associations of plasma levels of different sex
hormones with premature atrial or ventricular contractions in
premenopausal women. Materials and Methods: We conducted a prospective
study which included women in late reproductive age who presented with
palpitations during an eight-month period. A 12-lead
electrocardiography, a transthoracic echocardiogram, blood samples, and
24-hour rhythm Holter were conducted on the third day of the menstrual
cycle. Results Overall, 93 healthy premenopausal women with a median age
of 42 years were enrolled. QTc interval was within normal limits in all
patients. The 24 h range of premature atrial contractions (PACs) and
premature ventricular contractions (PVCs) was 0-6450 and was 0-21,230,
respectively. The median number of PVCs was 540 and the median number of
PACs was 212, respectively. In total, 51 patients (54.8%) had a
frequency of PVCs > 500/24 h and 37 patients (39.8%) had a frequency of
PACs > 500/24 h, respectively. No statistically significant association
was shown between any hormone and the frequency of PACs. Regarding PVCs,
patients with a PVCs frequency > 500/24 h had higher estradiol levels
compared to patients with PVCs less than 500/24 h (median 60 pg/mL
versus 42 pg/mL, p = 0.02, OR: 1.01). No association was found between
PVCs and other hormones. Conclusions: In premenopausal healthy women,
higher estradiol levels are independently associated with increased
PVCs. This suggests that estradiol in late reproductive stages may exert
proarrhythmic effects