Abstract
OBJECTIVE: To assess the effect of chronic deconditioning on cardiac dimensions and function in subjects with high-level spinal cord injury (SCI), who represent a human in-vivo model of extreme inactivity. DESIGN: Cross-sectional study. SETTING: University medical center. PARTICIPANTS: Seven men with tetraplegia and 7 able-bodied controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Echocardiographic measurements of resting cardiac dimensions, systolic function, and global and long-axis diastolic function. RESULTS: Left ventricular mass index was significantly lower in the subjects with SCI than in the controls (90.8+/-26 g/m(2) vs 122+/-28.9 g/m(2); P=.05). In addition, dimensions of left ventricle, left atrium, and vena cava inferior were all significantly reduced in the subjects with SCI compared with controls (P<.05). There were no differences between the groups for any of the parameters reflecting systolic and global and long-axis diastolic function. CONCLUSIONS: Tetraplegia is associated with a reduction in cardiac mass and dimensions. Resting diastolic and systolic function is not altered with continued exposure to inactivity, however, which suggests a remodeling of the heart as a physiologic adaptive process.
