Cardiac physiology in post myocardial infarction patients: the effect of cardiac rehabilitation programs—a systematic review and update meta-analysis

Cardiac rehabilitation program (CRP) is a recognized non-pharmacological modality to decrease mortality after acute myocardial infarction (AMI) events. We aimed to evaluate the effect of CRP on the cardiac physiology in patients post myocardial infarction (MI). Online database search of PubMed, MEDLINE, EMBASE, SCOPUS, COCHRANE, and GOOGLE SCHOLAR were performed (1988–Mar 2016); key bibliographies were reviewed. Studies comparing post MI patients who were enrolled in a CRP to those who were not, were included. Standardized mean difference (SMD) with the corresponding 95% confidence intervals (CI) by random and fixed effects models of pooled data were calculated. Study quality was assessed using CONSORT criteria. Outcomes of interest measured included resting and maximum heart rate (HR), peak VO₂, ejection fraction (EF%), wall motion score index (WMSI), left ventricular end diastolic volume (LVEDV) in cardiac rehabilitation patients versus control. Search strategy yielded 147 studies, 23 studies fulfilled the selection criteria, 19 of which were RCTs. These included a total of 1,683 patients; 827 were enrolled in a CRP while 855 did not receive the intervention. Median age was 58 years. There was no significant difference between the two groups in terms of age, comorbidities, severity of CAD, baseline EF or HR. Meta-analysis of data included demonstrated that CRP patients had lower post-intervention resting HR than non-CRP patients (SMD: −0.59; 95% CI: −0.73 to −0.46, fixed effect model P<0.05). EF% was significantly improved after CRP compared to control (SMD: 0.21; 95% CI: 0.02 to 0.40, P=0.03). Peak VO₂ was significantly improved by CRP (SMD: 1.00; 95% CI: 0.56 to 1.45; P<0.0001). LVEDV was significantly less in CRP patients (SMD: −0.31; 95% CI: −0.59 to −0.02, fixed effect model P<0.05). WMSI was significantly less in CRP patients (SMD: −0.41; 95% CI: −0.78 to −0.05, P=0.024). CRP improves cardiac function in post MI patients. This may explain the reported improvement of functionality and mortality among those patients. Further randomized trials may help evaluate the long-term benefits of CRP.