QTc Prolongation in Transgender Female Adolescents Receiving Gonadotropin-releasing Hormone Agonist: Preliminary Data
2Pediatric Cardiology Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv.
Background:
The QT interval corrected for heart rate (QTc) is used as a marker of ventricular arrhythmia risk. Testosterone has a shortening effect on QTc length, and the QTc interval in cisgender males is shorter than in females. Transfemale adolescents are treated with GnRH agonists (GnRHa) that suppress testosterone secretion and might prolong the QT interval and increase the risk for arrhythmia.
Aim:
To analyze QTc interval in transfemale adolescents before and after receiving GnRHa and after estrogen treatment.
Methods:
In this prospective study QTc was analyzed in transfemales who started treatment at Tanner stage 4/5, before and after GnRHa treatment and after adding estrogen. QTc was measured using the Hodges formula to correct for heart rate. Prolonged QTc was considered >450 ms.
Results:
Twenty transfemales were include .QTc in the 10 participants that initiated GNRHa alone was significantly prolonged compared to baseline (381.9±17.71 vs 404.48±22.19 ms,respectively,p=0.015), but did not increase>450 ms. Of these 10 participants, 7 continued to estrogen treatment. QTc was observed to increase after GnRHa treatment and decrease back after adding estrogen treatment (386.4±19.8 vs 413.7±19.9 vs 402.0±23.5 ms,respectively, p=0.05). QTc did not increase significantly in 17 participants treated with both GNRHa and estrogen compared to baseline.
Conclusion:
QTc interval may prolong after GnRHa treatment in Tanner 4-5 transfemales adolescents, while estrogen and GnRHa combined treatment may not affect QTc. This may be of concern, as incidence of mental health conditions requiring psychopharmacotherapy is high in transgender youth, with many psychiatric medications known to prolong the QT.
