Author(s): OESTREICHER, S., AARON, B., VUILLE, C., GUFFI, T., OESTREICHER, M., NEYROUD, D., DAUCOURT, C., BAGGISH, A. , Institution: CHUV, Country: SWITZERLAND, Abstract-ID: 1376

INTRODUCTION:
The sport specificity of exercise-induced cardiac remodelling (EICR) and its implications for human performance and clinical assessment have been comprehensively documented in adult athletes. To date, spares data examining EICR in competitive pediatric athletes are available.
METHODS:
Competitive pediatric athletes participating in the endurance sport of Nordic ski racing were prospectively studied with transthoracic echocardiography at preseason (August 2023) and again the conclusion of their competitive season (March 2024). A control cohort of pediatric athletes participating in the strength sport discipline of alpine ski racing was similarly assessed cross-sectionally at single post-season time point (March 2024). EICR among endurance athletes (i.e. pre vs. post-season cardiac dimensions) was assessed using paired t-tests. The sport specificity of cardiac dimensions (i.e. post sesaon comparisons between nordic and alpine skiers) was examined using unpaired t-tests.
RESULTS:
A total of 34 nordic skiers were enrolled at baseline (age=12±1 years, female=59%, height=158±9 cm, body mass=45±10 kg). After 8 months of nordic skiing training and competition, a training effect was reflected by a decline in resting heart rate (84±15 vs. 79±19 beats/min., p<0.001). In this context, significant EICR was observed as manifest by increases in left ventricular (LV) posterior wall thickness (6.9±0.8 vs. 7.6± 0.8 cm, p<0.0001), LV chamber dimensions (43.7±4.0 vs. 45.2±3.9, p=0.02), and accentuation of LV diastolic function (lateral mitral annular E’ = 18±2 vs. 21±4 cm/s) while LV outflow track dimensions were unchanged (17.4±1.8 vs. 17.8±1.9, p =0.22). Compared to a similar cohort of 30 alpine skiers (age=12.0±1.0 years, female=50% height=153±9 cm, body mass=43±9 kg), pediatric nordic skiers demonstrated great LV mass (111±29 vs. 84±18 g) due to both thicker LV walls (7.6±0.8 vs. 7.0±0.8 cm, p=0.004) and larger LV chamber dimensions (45.2±3.9 vs. 41.5±4.0 cm, p<0.001). Eccentric LV geometry was observed in both groups (relative wall thickness = 0.33±0.03 vs. 0.33±0.04, p=0.83). At post-season, no athletes in either group demonstrated cardiac dimensions that reached the clinical gray-zone for EICR vs. pathologic cardiomyopathy as defined by a Z-score of > 2.0.
CONCLUSION:
After 8 months of training and competition, pediatric Nordic skiers demonstrated significant ECIR of the LV and a greater magnitude of LV hypertrophy than pediatric alpine skiers. However, no athletes participating in either skiing discipline demonstrated cardiac dimensions that fell into a diagnostic gray zone for pathologic hypertrophy. In aggregate, these data suggest that pediatric athletes undergo sport-specific EICR but that the magnitude of EICR is inadequate to reach levels of diagsnostic uncertainty. Larger and longer studies are warrented to resolve the full spectrum and clinical implications of EICR during the transition from youth to adulthood.