Exercise training early after acute myocardial infarction reduces stress-induced hypoperfusion and improves left ventricular function

Purpose: Exercise training might exert its beneficial effects on myocardial perfusion by inducing coronary vascular adaptations or enhancing collateralization. We evaluated whether long-term exercise-based cardiac rehabilitation started early after ST-elevation acute myocardial infarction (STEMI) improves myocardial perfusion and left ventricular (LV) function. Methods: Forty-six patients with recent STEMI and residual inducible hypoperfusion were randomized into two groups: 25 enrolled in a 6-month outpatient exercise-based cardiac rehabilitation programme (group T) and 21 discharged with generic instructions for maintaining physical activity and correct lifestyle (group C). All patients underwent cardiopulmonary exercise test and dipyridamole rest gated myocardial perfusion single photon emission computed tomography within 1 week after STEMI and at 6-month follow-up. Results: At follow-up, group T showed an improvement in peak oxygen consumption, oxygen pulse and in the slope of increase in ventilation over carbon dioxide output (all p <0.01) associated with a reduction of stress-induced hypoperfusion (p <0.01) and an improvement in resting and post-stress wall motion score indexes (both p <0.01), resting and post-stress wall thickening score indexes (both p <0.05) and resting and post-stress LV ejection fraction (both p <0.05). On the contrary, no changes in cardiopulmonary indexes, myocardial perfusion and LV function parameters were observed in group C at follow-up. Conclusion: Exercise training started early after STEMI reduces stress-induced hypoperfusion and improves LV function and contractility. Exercise-induced changes in myocardial perfusion and function were associated with the absence of unfavourable LV remodelling and with an improvement of cardiovascular functional capacity.