Abstract
PURPOSE: We sought to evaluate the effect of intensive physical training on left ventricular (LV) hemodynamic forces (HDF) in athletes. METHODS: Forty professional endurance athletes were evaluated at the beginning of their training cycle (off-season) and after a period of aerobic isotonic dynamic exercise (peak training period) using cine cardiac magnetic resonance (CMR). Images were analyzed off-line using dedicated software. LV HDF for the whole cardiac cycle and the different cardiac phases were measured. Standard statistics were used to compare off-season and peak training period values. RESULTS: The average sport experience was 11 ± 7 yr. There were no differences in LV volumes, stroke volume, LV ejection fraction, and LV mass between off-season and peak training CMR. Similarly, there were no changes induced by physical training in the strain parameters. Physical training induced a significant increase of the longitudinal HDF (18.7 vs 21.2, P = 0.023) and an increase of the transverse HDF (3.4 vs 4.0, P = 0.048) throughout the entire heartbeat. After physical training, the peak values and the hemodynamic work (expressed as area under the curve) of the first part of the systole were significantly higher compared with off-season values (63.9 vs 53.9 ( P = 0.034); 4.67 vs 3.79 ( P = 0.015), respectively). The difference in the elastic rebound between off-season and peak training (-0.22 vs -0.37) did not reach statistical significance ( P = 0.056). CONCLUSIONS: Intense physical training induces an increase in LV HDF throughout the entire heartbeat, independent from geometric cardiac remodeling. The first part of the systole is the phase of the cardiac cycle that is mostly improved by intense physical training.