Exercise training increases myocardial perfusion in residual viable myocardium within infarct zone

PURPOSE: To study the effect of exercise training on the myocardial perfusion in the postinfarct myocardium. MATERIALS AND METHODS: Twenty-nine patients with stable chronic myocardial infarction were randomly assigned to either a training group (N = 17) or a control group (N = 12). The training group received a 3-month exercise program. Cardiovascular MR was first performed before the training to establish a baseline, and subsequently performed once again upon conclusion of the program. Late gadolinium enhancement was used both to define the infarct and remote zones and to quantify the ratio of the residual viable myocardium (VMR) within the infarct zone. The myocardium was divided into subendocardial and subepicardial layers with equal thickness. The interval change of myocardial perfusion reserve (MPR) was computed for each zone and layer. The association between the exercise-induced perfusion change and VMR was analyzed for layers of the infarct zone. RESULTS: In the training group, the remote zone showed significantly increased MPR. The infarct zone showed no perfusion change in the subendocardial layer, but it demonstrated significantly increased MPR in the subepicardial layer. In the infarct zone, the change in MPR was associated with VMR. CONCLUSION: In chronic myocardial infarction, the exercise-induced perfusion change in the infarct zone is proportional to the amount of residual viable myocardium.