Electrocardiographic changes in transgender patients on gender-affirming hormone replacement therapy

Differences in electrocardiogram (EKG) measurements exist between cisgender men and cisgender women, with men typically exhibiting shorter QTc intervals, longer QRS durations, and longer PR intervals. Limited data describe the effects of gender-affirming hormone replacement therapy (HRT) on EKG parameters in transgender individuals.

To evaluate electrocardiographic changes associated with HRT in transgender patients.

This retrospective, single-institution cohort study included transgender women and transgender men receiving estrogen or testosterone HRT with available pre- and post-HRT EKGs. Demographics and EKG measurements were collected and compared using paired t-tests and Wilcoxon signed-rank tests.

Thirty patients met inclusion criteria (17 transgender women, 13 transgender men). Among transgender women, QRS duration decreased from a median of 96.0 (92.0-106.0) ms pre-HRT to 94.0 (86.0-100.0) ms post-HRT (p = 0.022). P-wave amplitude decreased in leads V₃-V₄ (p = 0.024, p = 0.037), and R-wave amplitude decreased in leads V₄-V₆ (p = 0.008, p = 0.025, p = 0.011, respectively) post-HRT. T-wave amplitude was lower in transgender women in lead V₂ (p = 0.016) and higher in transgender men in leads V₂-V₃ post-HRT (p = 0.015, p = 0.024). Stratification by race showed an increase in heart rate in Black transgender women from 71.6 ± 12.8 to 84.9 ± 19.2 beats per minute post-HRT (p = 0.015). Similar differences in P-, R-, and T-wave amplitude were observed in Black transgender patients in select precordial leads.

HRT used for gender-affirming care is associated with electrocardiographic changes that trend toward patterns of the affirmed gender. Findings suggest baseline and follow-up EKGs should be standardized when initiating HRT. Larger studies are needed to clarify structural and arrhythmogenic implications.