Preserved cardiac function after chronic spinal cord injury

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 +/- 26g/m(2) vs 122 +/- 28.9g/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.