Severity of structural and functional right ventricular remodeling depends on training load in an experimental model of endurance exercise

Maria Sanz-de la Garza, Cira Rubies, Montserrat Batlle, Bart H. Bijnens, Lluis Mont, Marta Sitges, Eduard Guasch
2017 American Journal of Physiology. Heart and Circulatory Physiology  
Sanz-de la Garza M, Rubies C, Batlle M, Bijnens BH, Mont L, Sitges M, Guasch E. Severity of structural and functional right ventricular remodeling depends on training load in an experimental model of endurance exercise. Arrhythmogenic right ventricular (RV) remodeling has been reported in response to regular training, but it remains unclear how exercise intensity affects the presence and extent of such remodeling. We aimed to assess the relationship between RV remodeling and exercise load in a
more » ... exercise load in a long-term endurance training model. Wistar rats were conditioned to run at moderate (MOD; 45 min, 30 cm/s) or intense (INT; 60 min, 60 cm/s) workloads for 16 wk; sedentary rats served as controls. Cardiac remodeling was assessed with standard echocardiographic and tissue Doppler techniques, sensor-tip pressure catheters, and pressure-volume loop analyses. After MOD training, both ventricles similarly dilated (~16%); the RV apical segment deformation, but not the basal segment deformation, was increased [apical strain rate (SR): Ϫ2.9 Ϯ 0.5 vs. Ϫ3.3 Ϯ 0.6 s Ϫ1 , SED vs. MOD]. INT training prompted marked RV dilatation (~26%) but did not further dilate the left ventricle (LV). A reduction in both RV segments' deformation in INT rats (apical SR: Ϫ3.3 Ϯ 0.6 vs. Ϫ3.0 Ϯ 0.4 s Ϫ1 and basal SR: Ϫ3.3 Ϯ 0.7 vs. Ϫ2.7 Ϯ 0.6 s Ϫ1 , MOD vs. INT) led to decreased global contractile function (maximal rate of rise of LV pressure: 2.53 Ϯ 0.15 vs. 2.17 Ϯ 0.116 mmHg/ms, MOD vs. INT). Echocardiography and hemodynamics consistently pointed to impaired RV diastolic function in INT rats. LV systolic and diastolic functions remained unchanged in all groups. In conclusion, we showed a biphasic, unbalanced RV remodeling response with increasing doses of exercise: physiological adaptation after MOD training turns adverse with INT training, involving disproportionate RV dilatation, decreased contractility, and impaired diastolic function. Our findings support the existence of an exercise load threshold beyond which cardiac remodeling becomes maladaptive. NEW & NOTEWORTHY Exercise promotes left ventricular eccentric hypertrophy with no changes in systolic or diastolic function in healthy rats. Conversely, right ventricular adaptation to physical activity follows a biphasic, dose-dependent, and segmentary pattern. Moderate exercise promotes a mild systolic function enhancement at the right ventricular apex and more intense exercise impairs systolic and diastolic function. right ventricle; endurance exercise; fibrosis; training load; cardiac remodeling * M. Sanz-de la Garza and C. Rubies contributed equally to this work. Address for reprint requests and other correspondence: E. Guasch,
doi:10.1152/ajpheart.00763.2016 pmid:28550178 fatcat:zhfsis5scvcsjp5nur3xa6g7te