Alterations in left ventricular filling consecutive to altitude training in a rat model: impairment in preload conditions

Aim Specific cardiac adaptations leading to lack of improvement in left ventricular (LV) filling have been recently established consecutive to altitude training (AT). The aim of this study was to investigate the contribution of LV relaxation properties, preload and dimensions in the explanation of this hypoxia (with or without training)-induced absence of LV filling enhancement. Methods Male rats were randomly assigned to four groups: Normoxic groups (PIO2 = 159 mmHg) with (NT) or without (N) training, and hypoxic groups (PIO2 = 110 mmHg) with (CHT) or without training (CH). Cardiac adaptations were evaluated by Doppler-echocardiograhy, cardiac weighing, aortic pulsed-Doppler transducer and intraventricular pressure variations. Results Our major finding was that the lack of LV filling improvement consecutive to AT was not accounted for by deleterious effects of hypoxia exposure on LV relaxation properties but rather explained by altitude-induced cardiac morphological and preload alterations.