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Comparing six QT correction methods in an athlete population

Abstract:

Sinus bradycardia and prolonged QT interval corrected (QTc) are frequently noted on resting ECG in athletes. Possible explanation for longer QT includes inaccuracies in the correction formula. This study aimed to compare six formulas commonly used to correct QT interval duration by heart rate (HR): Bazett, Hodges, Fridericia, Framingham, linear and exponential regression. Population studied was of 1179 Caucasian people. QTc were calculated using the six formulas specified, as well as the correlation coefficients between QTc and HR. Additionally, QTc was determined for several thresholds of bradycardia (63bpm-43bpm). As expected, QTc is longer in women and in athletes (p<10 -4) for all correction formulas. QTc in bradycardia population were different from each formula: with Bazett formula, it is longer in non-bradycardia than in bradycardia group (404.10±24.6 ms vs. 384.70±24.37 ms, p<10-4), with Fridericia formula, there was no difference between groups (394.12±24.60 ms vs. 394.71±23.89 ms, p N.S.), and with Hodges formula, it is longer in bradycardia group (393.35±22.78 ms vs. 400.35± 27.21 ms, p<10-5). Finally, from our results, the best-adapted formula to overall thresholds of non-bradycardia is Fridericia one. Most of the correction formulas explored give an acceptable QTc approximation for a first screening in athletes. Further works should be addressed to the study of athlete's ventricular repolarization in a multifactorial way. © 2012 CCAL.