ESPE Abstracts

Background and Aim: Gonadotropin-releasing hormone analogs (GnRHa’s) are the standard medical treatment for precocious puberty. Studies on their side effects in adults have shown that these drugs can cause changes in electrocardiography (ECG) along with some cardiovascular effects; however, the number of studies on children is limited. This study aims to investigate the effect of these drugs on ECG parameters in children diagnosed with central precocious puberty (CPP).

Materials and Methods: This prospective study included 44 girls who presented to Adana City Hospital Pediatric Endocrinology Clinic between April 2020 and December 2021 and were initiated on GnRHa treatment (Leuprolide acetat) with a diagnosis of CPP. ECG was performed before the treatment for patients whose diagnosis was confirmed after hormonal and biochemical evaluations. ECG was repeated at 6 months of treatment in those who regularly used the drug. While puberty examination and laboratory values were evaluated by a pediatric endocrinologist, ECG parameters were estimated by the same pediatric cardiologist who was unaware of the clinical status of the patients. Estimated parameters included heart rate, PR, QRS, QT and, QTc interval, QT and, QTc dispersion.

Results: The mean age of the children who participated in the study was 9.13±1.55 years. The mean dose of GnRHa was 112.87±33.01 μg/kg. The comparison of the pre-treatment and 6-month ECG parameters of the patients revealed a prolonged QT interval after the treatment, with a statistically significant difference (P<0.001). There was no significant difference in pre- and post-treatment values of PR, QRS and, QTc interval, QT, and QTc dispersion (P>0.05). Multivariate linear regression analysis was performed to determine the correlations between ECG parameters and GnRHa dose (μg/kg). For the adjusted regression model, a significant negative correlation was observed between GnRHa dose and PR, QRS, and QT interval (P=0.039, P=0.004, P=0.026, respectively), while no significant correlation was found between GnRHa dose and QTc interval (P=0.386).

Conclusion: Despite a significant increase in QT interval on ECG with GnRHa compared to pre-treatment ECGs in children, this increase was attributed to variability in heart rate. There was no significant change in other parameters studied, including, QT and, QTc interval, QT and, QTc dispersion after the use of GnRH agonists. Therefore, regular ECG monitoring should be considered after the initiation of GnRHa treatment though GnRHa are believed to be safe in childhood as there is not enough evidence yet.