Abstract 12808: Genetic Heart Disease and Gender-Affirming Hormone Therapy in Transgender Individuals: Potential Pro-Arrhythmic Considerations

Background: Sex hormones influence the arrhythmogenic risk for various genetic heart diseases (GHDs) including long QT syndrome (LQTS), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and idiopathic ventricular fibrillation (IVF). Although exogenous hormones are used frequently in transgender medicine for gender-affirming hormone therapy (GAHT), the effect of such treatments on sudden cardiac death (SCD) risk in transgender patients with a GHD is unknown. Objective: To describe the prevalence and spectrum of transgender patients with GHD and to evaluate the impact of GAHT on the treatment and outcomes of their underlying GHD. Methods: We performed a retrospective review of all patients seen and evaluated in Mayo Clinic’s Windland Smith Rice Genetic Heart Rhythm Clinic from January 1999-2022 to identify transgender patients. Clinical notes were reviewed for sex, gender identity, GAHT, and details of their GHD, therapy, and outcomes. Results: Among 1990 patients with a GHD, we found 7 patients (0.35%) who self-identify as a gender different from their chromosomal sex (transgender). Specifically, there were 4 patients who identified as transgender women (XY males at birth) and 3 as transgender men (XX females at birth). Five of seven patients (71%) have used forms of GAHT, with 2 patients on estradiol and 3 patients on testosterone. GHDs identified include LQT1 (2 transgender women), LQT3 (1 transgender man), LQT3/BrS overlap syndrome (1 transgender woman), genotype negative LQTS (1 transgender man), CPVT (1 transgender woman), and IVF (1 transgender man). Guideline-directed GHD therapy was optimized, not altered nor escalated, for all patients and no patients were advised against initiating GAHT due to perceived interactions. One of seven patients (transgender man with IVF) experienced a breakthrough cardiac event (BCE) while on GAHT, while the other 6 patients have had no BCEs. Conclusion: Although less than 0.5% of patients seen over 20+ years self-identified as transgender, their holistic care must include a careful discussion of the possible cardiac risks associated with GAHT. Additional studies are needed to determine the potential pro-arrhythmic risk of GAHT.