Analysis of athlete QT intervals by age: Fridericia and Hodges heart rate corrections outperform Bazett for athlete ECG screening.

BACKGROUND: Cardiac screening of elite athletes including a 12­lead electrocardiogram (ECG) is recommended by numerous international bodies. Current athlete ECG interpretation guidelines recommend the Bazett method to correct the QT interval (QTc). OBJECTIVE: This study sought to investigate normative QTc changes by age using athlete screening ECGs and different QT correction methods in a population of elite cricketers. METHODS: Initial cardiac screening ECGs from an existing database of elite Australian cricketers aged 14-35 years were examined. Average QT interval, QTcB (corrected QT-Bazett), QTcF (Fridericia), QTcH (Hodges), and heart rate (HR) were analyzed by age and sex. RESULTS: A total of 1310 athletes (66% male, 34% female) were included with mean age 19.1 years and mean heart rate 66.9 bpm (range 38-121 bpm). With increasing age, HR decreased and absolute QT increased. The pattern of QTc change with age differed depending on the method of correction: Bazett correction (QTcB) demonstrated a "dish-shaped" or broad U-shaped appearance; while Fridericia and Hodges corrections showed a linear increase in QTc from young to older age. The Bazett method had a stronger correlation of HR with QTc (R2 = 0.32) than either Fridericia (R2 = 0.0007) or Hodges (R2 = 0.009) methods. CONCLUSIONS: The Bazett method is not the most accurate QT correction in athletes, especially during adolescence. In elite cricketers, QTcB revealed a drop in QTc from adolescence to early adulthood due to mis-correction of the QT interval. The Fridericia method has the smoothest correction of HR and least QT variation by age and may be preferred for athlete screening.