Functional Improvement After Outpatient Cardiac Rehabilitation in Acute Coronary Syndrome Patients 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. Aim: Our study was aimed at assessing the relationship between functional improvement (evaluated with 6-min Walk Test—6MWT) and the improvement in left ventricular ejection fraction (LVEF) after CR. Methods: We collected data from 249 patients (age 66.79 ± 11.06 years; males 81.52%) with a recent history of Acute Coronary Syndrome that performed CR. The functional improvement after CR was expressed as the Δ between distance covered at the final versus the initial 6-min Walking Test (6-MWT), while LVEF was calculated with transthoracic echocardiogram at the beginning and at the end of the CR. Results: Patients were divided accordingly to their pre-rehab LVEF (≥ 55% vs < 55%). With superimposable age and baseline 6MWT distance covered (434.58 vs 405.12 m, p = 0.08), the latter group presented higher Δ meter values at 6MWT (167.93 vs 193.97 m, p = 0.018). However, no statistically significant positive correlation between Δ meters and Δ LVEF was found. Moreover, linear regression analyses found that nor baseline LVEF nor Δ LVEF were significant determinants of Δ meters when considering the whole group, with age, basal 6MWT and peak CK-MB as additional covariates in the model. Conclusion: Although it could be expected that an increase in LVEF is related to the functional improvement after CR, no significant correlation was found in our population.