Structural and functional remodeling for elite cyclists during exercise; pressure-volume loops and hemodynamic forces analysis

The study was designed to investigate the pattern of intraventricular hemodynamic forces (HDFs) and myocardial performance during exercise in elite cyclists (ECs). Transthoracic stress echocardiography was performed on 19 ECs and 13 age-matched sedentary controls (SCs) at three incremental exercise intensities based on heart rate reserve (HRR). Left ventricular (LV) HDFs were computed from echocardiography long-axis datasets using a novel technique based on endocardial boundary tracking, both in apex-base and latero-septal directions. Pressure volume (PV) loops were noninvasively investigated using the single-beat approach. Differences between groups were investigated using mixed model analysis. At PV loops, EC showed a steeper increase in stroke work compared with SC, without acute changes in ventricular capacity (EDVI20). Contractility, measured as ventricular elastance (Ees), increased during exercise with no difference between groups (P ¼ 0.625). At rest, EC had significantly lower heart rates and generated lower HDF than SC. However, during exercise, the pressure gradient developed by EC in systole, and therefore systolic HDF, was significantly higher than that developed by SC (P < 0.009), also showing a greater elastic rebound in late systole compared with SC (P < 0.032). Importantly, during early diastolic filling, EC showed lower HDF deceleration than SC (P < 0.043), indicating a facilitated relaxation of the left ventricle. Analysis of the HDF pattern during exercise shows the functional changes that occur in EC, characterized by increased HDF generation in systole, and facilitated relaxation in early diastole. This is the first time LV structural and functional remodeling is reported for elite cyclists during exercise.