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

<i>Purpose</i>: 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). <i>Method</i>: 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 <i>p</i> value. <i>Results</i>: 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. <i>Conclusions</i>: 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.

研究目的：本研究旨在明确运动训练（exercise training, ET）的不同启动时机，对心肌梗死（myocardial infarction, MI）后左心室（left ventricular, LV）功能不全患者的左心室重构与心肺康复的效应量是否存在差异。研究方法：本研究纳入通过OVID MEDLINE、EMBASE、PubMed及Web of Science检索得到的评估运动训练（ET）疗效的临床试验，采用STATA 11.0软件进行荟萃分析，结果以标准化均数差（standardized mean difference, SMD）及对应的95%置信区间（95% CI）和p值进行表述。研究结果：在心肌梗死后急性期启动运动训练方案时，患者的左心室重构与心肺容量康复改善最为显著。随着心肌梗死病程进展至愈合阶段，运动训练对左心室射血分数（left ventricular ejection fraction, LVEF）、左心室收缩末期直径（left ventricular end-systolic diameter, LVDs）及峰值摄氧量（peak VO₂）的获益效应逐渐减弱，甚至产生不良影响。心肌梗死后急性期启动运动训练并未显著增加主要不良心血管事件的发生率。敏感性分析结果显示，排除同一研究机构的文献后，运动训练仍可显著降低LVDs并提升峰值摄氧量，但对提升LVEF不再具有统计学意义，不过仍呈现出有利的变化趋势。研究结论：运动训练（ET）对心肌梗死（MI）后左心室功能不全患者的左心室重构与心肺康复具有积极作用，在心肌梗死后急性期启动运动训练可获得最大获益。康复启示：心肌梗死后急性期及愈合阶段早期启动运动训练安全且可行。在患者出院后（约心肌梗死后1周），早期运动训练可延缓左心室重构并改善心肺容量。运动训练对左心室重构与心肺容量康复具有积极作用，应将运动训练与药物一同视为心肌梗死二级预防的同等重要手段。