Key result
Detraining normalizes marked QT prolongation in competitive athletes within ~3 to 6 months.
Why the study?
QT interval prolongation interpretation in athletes is challenging due to possible exercise-induced electrophysiological adaptations and lack of clarity on its reversibility.
Does a detraining period resolve isolated QT interval prolongation in asymptomatic competitive athletes with negative genetic testing?
Case Report (n=4)
Does a detraining period resolve isolated QT interval prolongation in asymptomatic competitive athletes with negative genetic testing?
Marked QT interval prolongation in athletes with negative genetic testing can be a reversible phenotype related to training load that normalizes after detraining.
Detraining may normalize QT intervals in athletes; leaves open its utility to distinguish training effects from long QT syndrome pending larger studies.
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.
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Ungaro et al. (2026) conducted a case report in QT interval prolongation (n=4). Detraining vs. Baseline (intraindividual comparison) was evaluated on Normalization of QT interval and corrected QT intervals. Detraining for 3-6 months resulted in complete normalization of the QT and corrected QT intervals in all 4 competitive athletes presenting with marked QT interval prolongation.
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