The effects of progestin-only hormone treatment on QT interval in the adolescent female

Background: Prolongation of the ECG derived QT interval predicts increased risk for sudden life-threatening arrhythmias. Many medicines are known to prolong the QT interval though current data demonstrate that progesterone given to premenopausal females <18 years shortens the QT interval by six msec. This effect may be used to treat individuals with abnormal prolongation of the QT interval. Hormone progestin is used to treat a number of conditions in post-menarche females >18 years old. The effects of this treatment on the corrected QT (QTc) in this population are unknown. Objective: To describe the effect of exogenous progestin on the QTc in adolescent females. Methods: In post-menarcheal females, <18 years old, using no medications with known ECG effects, we compared QTc in milliseconds (ms) on ECG evaluations in those taking exogenous progestin vs those who are not. Descriptive statistics were used to compare the groups. Results: There were 40 controls and 21 treated participants. The age range was 10 - 17 years. There were no differences between the groups with regard to race, height, weight, BMI, or blood pressure. In the controls, the mean QTc was 403 +/-19 milliseconds (ms) vs. 397 +/-15 ms in those treated (p=0.22). Those on progestin therapy had a shorter QTc by the same magnitude difference (six ms) as the hormonal naive group in the adult literature. Conclusions: We report no adverse effects of progestin associated with QTc prolongation and a trend suggesting a decreased QTc in a population of post menarcheal-adolescent females.