Right ventricular structural and functional adaptation to regular, intense exercise in the young: a 3D echocardiographic study in adolescent athletes

Abstract Background Data are scarce concerning the exercise-induced structural and functional adaptations in adolescent athletes, especially concerning the right ventricle (RV). We aimed to characterize the RV contraction pattern and its associations with exercise capacity in a large cohort of adolescent athletes using 3D (three dimensional) echocardiography. Results We enrolled 215 adolescent athletes (16±1 years, 169 males, 12±6 hours of training/week) and compared them to 38 age- and sex-matched healthy, sedentary children. 3D echocardiographic datasets were acquired. We measured the biventricular end-diastolic volume indices (EDVi) and ejection fractions (EF) along with left ventricular (LV) mass index (LVMi) using dedicated software. We also determined the relative contributions of longitudinal EF (LEF/RVEF) and radial EF (REF/RVEF) to the RVEF. Same-day cardiopulmonary exercise testing was performed to calculate VO2/kg. LV and RV volumes and LV mass were higher in athletes compared to controls (athletes vs. controls; LV EDVi: 80±13 vs 64±10, RV EDVi: 81±14 vs 68±10 ml/m2, LVMi: 84±14 vs 68±13 g/m2, p<0.01). Notably, both LV and RVEFs were significantly lower (LVEF: 57±4 vs 61±3, RVEF: 55±5 vs 60±5%, p<0.001). Interestingly, while the relative contribution of radial shortening to the global RV EF was also reduced (REF/RVEF: 0.40±0.10 vs 0.49±0.06, p<0.001), the contribution of the longitudinal contraction was significantly higher in athletes (LEF/RVEF: 0.45±0.08 vs 0.40±0.07, p<0.01). The supernormal longitudinal shortening correlated with a higher VO2/kg (r= 0.138, P = 0.044). Conclusions Similarly to the adult athlete’s heart, the cardiac adaptation of adolescent athletes comprises higher biventricular volumes and lower resting functional measures with supernormal RV longitudinal shortening. Our study suggests that characteristic exercise-induced structural and functional cardiac changes are already present in childhood.