The effects of different initiation time of exercise training on left ventricular remodeling and cardiopulmonary rehabilitation in patients with left ventricular dysfunction after myocardial infarction

Purpose: The purpose of this study was to determine whether different initiation of exercise training (ET) produces different effect sizes for left ventricular (LV) remodeling and cardiopulmonary rehabilitation in patients with LV dysfunction after myocardial infarction (MI). Method: Trials evaluating ET outcomes identified by searches in OVID MEDLINE, EMBASE, PubMed and WEB OF SCIENCE were used. Meta-analysis was conducted with the use of the software STATA 11.0. The results were expressed as the standardized mean difference (SMD), with corresponding 95% CI and p value. Results: The largest changes in LV remodeling and cardiopulmonary capacity rehabilitation were obtained when programs began the acute phase after MI. With the healing of MI, the beneficial effects of ET on LV ejection fraction (LVEF), LV end-systolic diameter (LVDs) and peak VO2 were gradually weakened even worse. The incidence of major adverse cardiac events was not significantly increased in acute phase post-MI. Sensitivity analyses show that ET still had significant effect in reducing LVDs and increasing peak VO2, while ET no longer had statistical effect in increasing LVEF but showed favorable trends when the same research institution's works were excluded. Conclusions: ET has favorable effects on LV remodeling and cardiopulmonary rehabilitation in LV dysfunction post-MI patients. The greatest benefits are obtained when ET starts at the acute phase following MI.Implications for RehabilitationEarly exercise training is safe and feasible in acute and healing phase after myocardial infarction.Early exercise training could attenuate LV remodeling and improve cardiopulmonary capacity in patients with myocardial infarction after hospital discharge (around one week post-MI).Exercise training has favorable effects on LV remodeling and cardiopulmonary capacity rehabilitation. Exercise training should be treated to have the same roles with drugs in secondary prevention of myocardial infarction.