Prevalence and significance of an isolated long QT interval in elite athletes

Identification of a prolonged, corrected QT (QTc) interval in athletes may be a recommendation for disqualification from competitive sports. However, the prevalence and diagnostic significance of an isolated prolonged QTc in asymptomatic athletes without familial disease is unknown.

Between 1996 and 2006, 2000 elite athletes (mean age, 20.2 years) underwent 12-lead ECG and 2-D echocardiography. The QT interval was corrected for heart rate (QTc). Athletes with QTc > 460 ms underwent 48 h Holter monitor and an exercise stress test. All athletes with a prolonged QTc interval were offered genetic testing and first-degree relatives were invited for ECG. The QTc was prolonged in seven (0.4%) athletes ranging from 460 to 570 ms. Three athletes had a QTc value of >500 ms and all exhibited one of: paradoxical prolongation of QTc during exercise, a confirmatory genetic mutation, or prolonged QTc in a first-degree relative. In contrast, none of the athletes with a QTc value of <500 ms had any other features to indicate long QT syndrome (LQTS).

The prevalence of prolonged QTc in elite athletes is 0.4%. A QTc of >500 ms is highly suggestive of LQTS. A QTc of <500 ms in the absence of symptoms or familial disease is unlikely to represent LQTS in elite athletes.