Ratio of early mitral inflow peak velocity to flow propagation velocity predicts training effects of cardiac rehabilitation in patients after acute myocardial infarction

Objective: To use the ratio of early mitral inflow peak velocity (E) to mitral flow propagation velocity (FPV) measured in the early phase of myocardial infarction (early phase E/FPV) to evaluate the training effects of 8 weeks' cardiopulmonary rehabilitation in patients post-myocardial infarction. Design: Single-blinded, randomized control trial. Participants: Eighty-seven patients with acute myocardial infarction who had undergone primary coronary intervention. Methods: Participants were enrolled randomly to either the cardiac rehabilitation or the control group. The rehabilitation group followed an 8-week supervised rehabilitation programme. All patients completed exercise testing and echocardiography at both the beginning and at 8-week follow-up. Results: The value of E/FPV was significantly reduced at 8-week follow-up in the rehabilitation group (p=0.005). After cardiac rehabilitation, the increase in peak V_O2 (p=0.002) and cardiac clinical outcome (composition of mortality, cardiac readmission rate, and revascularization rate) (p=0.001) were significantly greater in patients with an early phase E/FPV <1.5 than in patients with early phase E/FPV ≥1.5. There were no significant differences in the increase in peak V_O2 and cardiac clinical outcome in patients with early phase E/FPV ≥ 1.5. Conclusion: Early phase E/FPV <1.5 predicts more beneficial effects of cardiac rehabilitation in post-acute myocardial infarction patients who have undergone primary coronary intervention.