Effect of cardiac rehabilitation on myocardial perfusion reserve in postinfarction patients.

Cardiac rehabilitation is believed to increase myocardial perfusion reserve (MPR), but this has not been adequately studied because of poor delineation of infarcted myocardium in previous studies. The purpose of this study was to determine the effect of cardiac rehabilitation on MPR in the remote and infarcted myocardium with contrast-enhanced magnetic resonance imaging; 39 postinfarction patients were recruited for this study and randomly assigned to a training group (n = 20) or a nontraining group (n = 19). Those in the training group participated in a 3-month rehabilitation training program at an exercise intensity of 55% to 70% of peak oxygen uptake (VO2); those in the nontraining group continued their usual lifestyle. Nineteen age-, weight-, and height-matched subjects without cardiovascular risk factors were selected as healthy controls. After myocardial infarction, a reduction in perfusion reserve was seen not only in the infarcted myocardium, but also in the remote myocardium. In the training group, exercise capacity increased by 15% (p <0.01), to the same level as in healthy controls. The post-training MPR increased in both remote (30%, p <0.01) and infarcted myocardium (25%, p <0.05) and reached the same level as in healthy controls. The change in exercise capacity correlated with the change in MPR in the remote myocardium (r = 0.55, p <0.001 for peak VO2). In the nontraining group, exercise capacity and MPR were unchanged. In conclusion, cardiac rehabilitation improves perfusion reserve in both infarcted and remote myocardium, with a parallel increase in exercise capacity.