The Spectrum of Change in the Elite Athlete's Heart.

Background: Extreme levels of both strength and aerobic training result in increased left ventricular (LV) and right ventricular (RV) volumes and LV mass, a key component of athletes' heart. The aim of this study was to document temporal changes in the hearts of elite professional athletes (Australian Football League players) over a 2- to 6-year period.

Methods: Thirty-six Australian Football League players with 3.5 ± 2.7 years of professional training at enrollment prospectively underwent echocardiography in the preseasons of 2009, 2013, and 2015. At each time point, LV dimension and contractility and RV dimension, area, and contractility were measured using two-dimensional echocardiography. LV volumes, ejection fraction, and mass were measured using three-dimensional echocardiography.

Results: The mean age at baseline was 21.8 ± 2.6 years (range, 18-29 years). Most players (n = 20) had increases in fitness between studies (mean maximal oxygen uptake, 62.3 ± 3.6 vs 64.3 ± 2.1 mL/kg/min). In these players, there were increases in both LV and RV size and in LV mass. Players who were >25 years of age at their baseline scans demonstrated a trend toward increases in RV size and a decline in RV global longitudinal strain. Fitness level and playing position also affected the degree of physiological athletic cardiac remodeling.

Conclusions: Australian football is a sport that involves both strength and aerobic training. This study, unique in its length and detail, demonstrates that remodeling in the athlete's heart is a continuous spectrum of change. This remodeling occurs over time in response to high levels of exercise, with proportional increase in LV mass and LV dimensions.