Favourable effects of exercise-based Cardiac Rehabilitation after acute myocardial infarction on left atrial remodeling

Background: Left atrial enlargement is an important predictor of cardiovascular outcomes in patients after acute myocardial infarction. Whilethe favourable effect of exercise exercise-based Cardiac Rehabilitation (CR) on postinfarction LV remodeling has been well documented, those on LA remodeling have yet to be defined. This study investigated the effects of CR on LA remodeling in postinfarction patients with moderate left ventricular (LV) dysfunction. Methods: Sixty postinfarction patients were randomised randomized into two groups, each composed of 30 patients: group T (LVejection fraction (EF) 43.7±4.2%, mean±SD) entered a 6-month CR program, whereas group C (EF 44.7±4.4%, P=ns) did not. Doppler echocardiography and cardiopulmonary exercise test were performed upon enrolment and at 6-month. Results: At 6-month, trained patients showed a significant (Pb0.001) improvement in peak oxygen consumption (ΔVO2peak=+5.2±2.1ml/kg/min) and a reduction in LA (ΔLAVMAX=−1.9±3.7 ml/m2) and in LV volumes (ΔLVEDV=−3.6±4.4 ml/m2). At 6-month, untrained patients showed LAVMAX (+3.6±4.4 ml/m2, Pb0.001) and LV dilation (+4.2±5.1 ml/m2, Pb0.001; group T vs. C, Pb0.001); whereas no significant changes in VO2peak were observed. Multiple linear regression analysis showed that age (β=0.442, Pb0.001), inclusion in the training group (β=−0.599, Pb0.001), E/A ratio (β=−0.210, P=0.038), LVEDV (β=0.376, Pb0.001), and LVEF (β=−0.279, P=0.007) are significant predictors of LA remodeling. Conclusions: Six-month exercise-based CR in postinfarction patients with mild to moderate LV dysfunction induced a favourable LA remodeling.