Disproportionate Exercise Load and Remodeling of the Athlete's Right Ventricle

Purpose: There is evolving evidence that intense exercise may place a disproportionate load on the right ventricle (RV) when compared with the left ventricle (LV) of the heart. Using a novel method of estimating end-systolic wall stress (ES-s), we compared the RV and LV during exercise and assessed whether this influenced chronic ventricular remodeling in athletes. Methods: For this study, 39 endurance athletes (EA) and 14 nonathletes (NA) underwent resting cardiac magnetic resonance (CMR), maximal oxygen uptake (V?O2), and exercise echocardiography studies. LV and RV end-systolic wall stress (ES-s) were calculated using the Laplace relation (ES-s = Pr/(2h)). Ventricular size and wall thickness were determined by CMR; invasive and Doppler echo estimates were used to measure systemic and pulmonary ventricular pressures, respectively; and stroke volume was quantified by Doppler echocardiography and used to calculate changes in ventricular geometry during exercise. Results: In EA, compared with NA, resting CMR measures showed greater RV than LV remodeling. The ratios RV ESV/LV ESV (1.40 ± 0.23 vs 1.26 ± 0.12, P = 0.007) and RV mass/LV mass (0.29 ± 0.04 vs 0.25 ± 0.03, P = 0.012) were greater in EA than in NA. RVES-s was lower at rest than LVES-s (143 ± 44 vs 252 ± 49 kdyn·cm-2, P < 0.001) but increased more with strenuous exercise (125% vs 14%, P < 0.001), resulting in similar peak exercise ES-s (321 ± 106 vs 286 ± 77 kdyn·cm-2, P = 0.058). Peak exercise RVES-s was greater in EA than in NA (340 ± 107 vs 266 ± 82 kdyn·cm-2, P = 0.028), whereas RVES-s at matched absolute workloads did not differ (P = 0.79). Conclusions: Exercise induces a relative increase in RVES-s which exceeds LVES-s. In athletes, greater RV enlargement and greater wall thickening may be a product of this disproportionate load excess.