EARLY ELECTROCARDIOGRAM CHANGES IN HIGHLY TRAINED PREADOLESCENT FOOTBALL PLAYERS

Objective. To assess the early electrocardiogram (ECG) changes induced by physical training in preadolescent professional football players.

Design and methods. Ninety-four highly trained male football players (mean age —12,85 ± 0,84 years) competing in the Serbian Football League (at least 7 training hours/week) and 47 age-matched healthy male controls were enrolled in the study. They were screened by ECG and echocardiography at a tertiary referral cardiocentre. The control group had sedentary life style (less than 2 training hours/week). Characteristic ECG intervals and ECG voltage were compared and reference range was given for preadolescent footballers.

Results. Highly significant differences between preadolescent athletes and sedentary controls were registered in all ECG parameters: P wave voltage (p < 0,001), S wave (V1 or V2 lead) voltage (p < 0,001), R wave (V5 and V6 lead) voltage (p < 0,001), ECD sum of the S1,2 + V5,6 (p < 0,001), T wave voltage (p < 0,001), QRS complex duration (p < 0,001), T wave duration (p < 0,001), QTc interval duration (p < 0,001) and R/T ratio (p < 0,001). No differences were registered in PQ interval duration between these two groups (p > 0,05). QTc interval duration in athletes was not very strongly, but indeed positively correlated with left atrium dilatation, left ventricular (LV) end-systolic and end-diastolic dimensions, LV myocardial index (LVMI), LVM/body surface area (BSA)1,5 and LVM/h2,7 indices. There was no correlation between QTc interval duration and LVM as well asLV wall thickness.

Conclusions.ECG changes are present in the early stage of athletes’ heart remodeling. QTc prolongation could be the early ECG marker of physiologicalLV remodeling in young preadolescent footballers.

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