The effects of supraphysiological oestrogen levels on ventricular repolarisation parameters

Area of Science:

• Cardiology
• Reproductive Endocrinology
• Clinical Electrophysiology

Background:

• Female sex is linked to higher rates of sudden arrhythmic death and torsades de pointes.
• Sex hormones significantly influence the cardiac conduction system.
• Existing research explores hormonal effects on cardiac electrophysiology.

Purpose of the Study:

• To investigate the impact of hormonal fluctuations, particularly supraphysiological estradiol, during in vitro fertilization (IVF) on ventricular repolarization.
• To assess changes in electrocardiographic parameters related to cardiac repolarization.

Main Methods:

• Study included women aged 23-39 undergoing controlled ovarian hyperstimulation (COH).
• Electrocardiograms (ECGs) and blood samples were collected pre- and post-COH.
• Analysis focused on ventricular repolarization parameters, including QTc interval and dispersion.

Main Results:

• Mean QTc interval significantly increased from 411.9 ms to 420.7 ms during peak estradiol levels (p=0.007).
• No significant changes were observed in corrected QT dispersion, Tp-e, J-T peak, or PR dispersion.
• The observed QTc prolongation did not reach pathological levels.

Conclusions:

• Supraphysiological estradiol during COH causes QTc interval prolongation.
• This effect may elevate ventricular arrhythmia risk in patients with congenital long QT syndrome or those on QT-prolonging medications.
• The QTc prolongation is generally not considered pathological in healthy individuals.