Different outcomes of a cardiac rehabilitation programme in functional parameters among myocardial infarction survivors according to ejection fraction

INTRODUCTION: Exercise-based cardiac rehabilitation (EBCR) is part of the management of patients who have suffered an acute myocardial infarction (AMI). Patients with a reduced ejection fraction (EF) comprise a higher-risk subgroup and are referred less often for these programmes. This study aimed at assessing the impact of the baseline EF on the functional benefits, as assessed by peak oxygen uptake (pVO(2)) and exercise duration, of an EBCR programme in AMI survivors. METHODS: Observational, retrospective cohort study including all patients admitted to a tertiary centre due to an AMI who completed a phase II EBCR programme after discharge, between November 2012 and April 2017. Functional parameters were assessed by a symptom-limited cardiopulmonary exercise test. RESULTS: A total of 379 patients were included [40.9% with reduced EF (<50%) at discharge]. After the programme, pVO(2) and exercise duration increased significantly (p < 0.001). Patients with a reduced EF had a lower pVO(2) and completed a shorter duration of exercise at the beginning and end of the programme. This group presented a higher increase in pVO(2) (p = 0.001) and exercise duration (p = 0.007). This was maintained after adjusting for age, gender, history of coronary artery disease, number of sessions, Killip classification, arterial hypertension, dyslipidaemia, diabetes mellitus, smoking status and baseline pVO(2). CONCLUSION: A phase II EBCR programme was associated with significant improvements in pVO(2) and exercise duration among AMI survivors, irrespective of baseline EF classification. Those with a reduced baseline EF derived an even greater improvement, highlighting the importance of EBCR in this subgroup of patients.