What is the central question of this study? Endurance athletes demonstrate altered regional right ventricular (RV) wall mechanics in comparison to non-athletic controls at rest, characterised by lower basal deformation. We tested the hypothesis that regional adaptations at the RV base reflects an enhanced functional reserve capacity in response to haemodynamic volume loading. What is the main finding and its importance? Free wall RV longitudinal strain is elevated in response to acute volume loading in both endurance athletes and controls. However, the RV basal segment, longitudinal strain response to acute volume infusion is greater in endurance athletes. Our findings suggest that training-induced cardiac remodelling may involve region-specific adaptation in the RV functional response to volume manipulation. Eccentric remodelling of the right ventricle (RV) in response to increased blood volume and repetitive haemodynamic load during endurance exercise is well established. Structural remodelling is accompanied by decreased deformation at the base of the RV free wall, that may reflect an enhanced functional reserve capacity in response to haemodynamic perturbation. Therefore, this study examined the impact of acute blood volume expansion on RV wall mechanics in 16 young endurance-trained males (aged 24±3 years) and 13 non-athletic male controls (aged 27±5 years). Conventional echocardiographic parameters, as well as longitudinal strain and strain rate were quantified at the basal and apical level of the RV free wall. Measurements were obtained at rest and following 7ml·kg-1 intravenous Gelofusine infusion with and without a passive leg raise. Following infusion, blood volume increased by 12±4% and 14±5% in endurance-trained individuals vs. controls, respectively (P = 0.264). Both endurance-trained individuals (8±10%) and controls (7±9%) experienced an increase in free wall strain from baseline, which was also similar following leg raise (7±10% and 6±10%, respectively; P = 0.464). However, infusion evoked a greater increase in basal longitudinal strain in endurance-trained vs. controls (16±14% vs. 6±11%; P = 0.048), which persisted following leg raise (16±18% vs. 3±11%; P = 0.032). Apical longitudinal strain and RV free wall strain rates were not different between groups and remained unchanged following infusion across all segments. Endurance training results in a greater contribution of longitudinal myocardial deformation at the base of the RV in response to a haemodynamic volume challenge, which may reflect a greater region-specific functional reserve capacity.
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