Disuse atrophy of the left ventricle in chronically bedridden elderly people

Abstract

In the elderly cardiac size and function are determined by their level of physical activity. In this study, we assessed by echocardiography, the anatomic and physiologic changes of the heart in 28 elderly patients who had no cardiac disease and who were chronically bedridden. The data obtained were compared to those obtained from a control group of 38 age and sex matched elderly people whose activities had not been restricted. Chronically bedridden patients had markedly smaller left ventricular dimensions in both end-diastole and end-systole and smaller left atrial dimensions than did control subjects (3.7±0.7 vs 4.7±0.6 cm, p<0.001, 2.4±0.8 vs 2.9±0.7 cm, p<0.02 and 3.2±0.5 vs 3.8±0.9 cm, p<0.01, respectively). Though the wall thickness of the interventricular septum did not differ between the study groups, the left ventricular posterior walls of the bedridden group were significantly thinner than in the control group (0.8±0.2 vs 1.0±0.2 cm, p<0.01). The bedridden group had a significantly lower stroke index (26.9±6.2 vs 47.0±11.1 ml/m2, p<0.001) and cardiac index (1.84±0.52 vs 3.15±0.631/min/m2, p<0.001) than did the control group. Left ventricular mass index and left ventricular systolic stress were significantly lower in bedridden patients than in control subjects (88.0±18.1 vs 143.5±30.9 g/m2, p<0.001, and 135.9±4.9 vs 186.6±35.7 103 dynes/cm2, p<0.001, respectively). The shortening fraction, however, did not differ between the two groups. The peak trans-aortic flow velocity of bedridden patients was not different from control subjects. The peak trans-mitral flow velocity in early diastole (R) of bedridden patients was significantly lower than in control subjects(0.44±0.15 vs 0.57±0.20 cm/s, p<0.01), while the decrease in peak trans-mitral flow velocity during atrial systole (A) was not significant. The ratio of A to R was significantly larger in the bedridden group than in the control group (1.8±0.7 vs 1.5±0.5, p<0.05). We conclude that long term bed rest causes disuse atrophy of the heart in the elderly by decreasing venous return, left ventricular work and wall stress. © 1992, The Japanese Circulation Society. All rights reserved.