270 QT duration in athletes, which limits?

Abstract

Absolute QT interval duration is classically corrected with heart rate according to the Bazett's formula (QTc). In general population, recommended upper limits of QTc values are 440 ms in males (M) and 450 ms in females (F). Upper limits of QTc duration in highly trained athletes make debate between European (440 ms in M and 460 ms in F) (1) and North-American recommendations (470 ms in M and 480 ms in F) (2). Lastly, a QTc > 500 ms seems highly suggestive of long QT syndrome in athletes (3). Thus, it is required to specify the upper limit cut-off value of QTc duration in a large population of athletes. In this multicentric and prospective study, a resting 12-lead ECG has been recorded in 1232 (357 F) French athletes. RR and QT intervals duration has been measured in DII with a tracer table on three successive cardiac cycles. QT and QTc duration values were respectively 394.8 (32.5) ms and 393.9 (24.8) ms. A long QT was observed in 24 athletes (1.9%, 11 F) according to European values and only in 2 athletes (0.2%, 1 F) according to North-American values. These last prevalences were near from those reported in athletes (3), but were higher than in general population (4). We observed no gender difference for QT and QTc [QT 391.0 (31.9) ms and QTc 389.1 (23.9) ms for M; QT 401.8 (33.2) ms and QTc 405.8 (23.1) ms for F]. The slope of RR -1 -QT relation was higher in F than in M (p<0.05, Fig. 1). Thus, for a similar resting RR, QT duration was longer in F. Limits of 470 ms in M and 480 ms in F for QTc duration seem more adapted in athletes. Further studies are needed concerning the individual risk evaluation for sports participation. (1) Pelliccia et al, Eur Heart J (2005) 45 : 1312-1375 ; (2) Maron et al, JACC (2005) 26 : 1422-1445 ; (3) Basavarajaiah et al, Eur Heart J (2007) 28: 2944-2949 ; (4) Goldenberg et al, JACC (2008) 51 : 2291-2300.