Functional improvement after cardiac rehabilitation is not related to improvement in left ventricular ejection fraction

Introduction: Cardiac rehabilitation (CR) improves the functional capacity and the prognosis of patients with coronary artery disease (CAD). Similar results have also been found in patients with dilated cardiomyopathy (DCM). Aim: To assess the relationship between functional improvement (evaluated with 6-minute walking test–6MWT) and the improvement in left ventricular ejection fraction (LVEF) after CR. Methods: we collected data from 260 patients that performed CR after an Acute Coronary Syndrome (ACS). The functional improvement after CR was expressed as the Δ between distance covered at the final versus the initial 6MWT normalized for the initial 6MWT, while LVEF was calculated with transthoracic echocardiogram at the beginning and at the end of the CR. Results: in the whole population functional improvement was 44.07% (baseline 6MWT 421.22 m vs follow-up 6MWT 597.28 m, p ≤ 0.05) while EF improvement was 2.48% (baseline EF 53.37% vs follow-up EF 55.91%, p ≤ 0.05). No significant correlation between the normalized Δmeter and ΔEF was founded. When patients were divided accordingly to their pre-rehab LVEF (≥ 55, 40–55 and < 50%) we found a lower baseline 6MWT distance in the second and the third group with a higher improvement only in the second group (40 vs 50 vs 43% respectively, p = 0.001). This latter group is also the one that presents the higher improvement in EF in comparison with the EF < 40% group (5 vs 3%, p = 0.04). No significant correlation between the normalized Δmeter and ΔEF was founded also when analysis was repeated in the different group depending on the EF values. Conclusions: Our data confirm the CR related functional improvement that is not related to the relative increase in LVEF.