QT Interval Prolongation in Athletes With Negative Genetic Testing and Complete Normalization After Detraining.

BACKGROUND

QT interval prolongation is traditionally associated with congenital or acquired long QT syndrome; however, its interpretation in athletes remains challenging because of possible exercise-induced electrophysiological adaptations.

CASE SUMMARY: We report a case series of 4 competitive athletes referred to our Sports Cardiology clinic after incidental detection of marked QT interval prolongation during preparticipation screening for sports eligibility. All individuals were asymptomatic, took no QT interval-prolonging drugs, had normal electrolyte levels, and had negative family screening and genetic testing. Following a detraining period of 3-6 months, repeat electrocardiograms showed consistent normalization of both QT interval and corrected QT intervals in all cases. The magnitude of the corrected QT interval reduction was substantial and observed intraindividually, independently of significant changes in heart rate.

CONCLUSIONS

These findings support the concept that, in some athletes, QT interval prolongation may represent a dynamic and reversible phenotype related to training load, termed "exercise-induced" long QT interval. Recognition of this pattern may help avoid misdiagnosis of congenital long QT syndrome and inappropriate restriction from competitive sports, although its long-term arrhythmic risk remains unclear.