Introduction: Development of left ventricular systolic dysfunction (LVSD) in acute coronary syndrome (ACS) patients significantly worsens their prognosis. In addition, LVSD is associated with diminished functional capacity (FC). Even though CRP is an essential tool for secondary prevention, some argue against an early cardiac rehabilitation program (CRP) referral of patients with LVSD.
Purpose: The aim of this study was to evaluate baseline clinical characteristics and compare the response to CRP of patients according to left ventricle ejection fraction (LVEF).
Methods: We performed a retrospective analysis of prospectively collected data on a cohort of patients referred to CRP after an ACS. Patients were divided into three groups: Preserved LVEF (pLVEF): LVEF≥50%, mid-range LVEF (mrLVEF): LVEF 40–49% and reduced LVEF (rLVEF): LVEF<40%. FC was assessed using metabolic equivalents (METs) achieved at a standard exercise test using Bruce protocol before and after CRP. We used ANOVA analysis and a mixed between-within analysis of variance.
Results: Of a total 586 patients, 370 (63.1%) had pLVEF, 115 (19.6%) had mrLVEF and 101 (17.3%) had rLVEF. Mean age was no different between groups (pLVEF: 53.9±10.0, mrLVEF: 53.8±9.6, rLVEF: 54.9±10.5, p=0.601) and most patients were males in all groups. Prevalence of diabetes, hypertension, active smoking, and dyslipidaemia were no different between groups. The main diagnosis in pLVEF patients was acute myocardial infarction (AMI) without ST elevation (51.4%) while in mrLVEF and rLVEF patients was AMI with ST elevation (73.0% and 76.2%, respectively). Coronarography showed obstructive disease of one coronary artery in majority of patients in all groups and percutaneous coronary intervention was the treatment of choice in pLVEF, mrLVEF and rLVEF groups. Baseline FC was better in pLVEF patients (9.2±2.3 METs), followed by mrLVEF (8.6±2.3 METs) and rLVEF patients (8.5±2.3 METs). After CRP, all groups significantly improved their FC (pLVEF: 10.8±2.1 METs, mrLVEF: 10.7±2.0 METs, rLVEF: 10.5±2.1 METs, within-groups partial Eta square 0.28, p<0.001). Comparing between-groups, improvement of FC was associated with LVEF, being mrLVEF patients the group that showed the best response to CRP (p=0.041).
Conclusion: FC ameliorated after CRP in all groups of patients despite different LVEF. Patients with mrLVEF were those who presented a better responder to CRP. Other studies are needed to further confirm this data in order to reinforce the referral of patients to CRP in spite of LVEF.