LAUSR

AIMS Little is known about the adaptation of the right ventricle (RV) to endurance exercise in children. The aim of this study was to assess the effects of 5months of intensive training on RV morphology and function in preadolescent endurance athletes. METHODS Ninety-four children were evaluated in this study. Fifty-seven male competitive swimmers (aged 10.8±0.2years) were evaluated before (baseline) and after 5months of the training (peak-training), and compared to 37 age- and sex-matched non-athlete children evaluated at baseline and after 5months of natural growth. All subjects were asymptomatic, with negative family history for cardiomyopathies. RESULTS At baseline no differences were found between athletes and controls for indexed RV outflow tract (RVOT) (18.5±2.7 vs. 16.8±5.0mm/m2, p=0.18) and RV basal end-diastolic diameter (EDD) (24.9±4.1 vs. 23.6±3.0mm/m2, p=0.15). After 5months, indexed RVOT and RV basal EDD significantly increased in athletes (20.2±2.9mm/m2 and 25.4±3.3mm/m2, p<0.0001 vs. baseline) while no differences were observed in controls (p=0.84 and p=0.25). Despite the increase in RV size, RV function remained normal in athletes, with no changes in RV fractional area change (p=0.97), s' value (p=0.22), and RV longitudinal strain (p=0.28). CONCLUSIONS Endurance training influences the growing heart of male preadolescent athletes with an addictive increase in RV dimensions, with a preserved RV function. Therefore, in children engaged in endurance sports the increase in RV size associated with normal RV function represents a physiological expression of the athlete's heart and should not be misinterpreted as an expression of incipient RV cardiomyopathy.