Increased Short-Term Variability of the QT Interval in Professional Soccer Players: Possible Implications for Arrhythmia Prediction

152 males of European descent, comprising 76 professional soccer players from the Hungarian Premier League (ages 16 to 39, mean 22.0±0.61 years) and 76 age-matched healthy sedentary controls (age 15 to 39, mean 22.0±0.54 years). Exclusions included excessive ectopic beats, non-sinus rhythm, repolarization abnormalities, permanent pacemaker, or symptomatic cardiac/pulmonary disease.

Professional soccer playing / intense physical conditioning (evaluated before and 20 minutes after a competitive game).

Age-matched healthy sedentary volunteers who do not participate in competitive sports.

Short-term beat-to-beat variability of repolarization (STV(QT)) and conventional ECG parameters (heart rate, QT interval, QTc).surrogate