Left Atrial Reverse Remodeling in Dilated Cardiomyopathy

Background: Left atrial (LA) dilation is associated with a worse prognosis in several cardiovascular settings but therapies can promote LA reverse remodeling. We aimed to characterize and define the prognostic implications of LA volume (LAVI) reduction in dilated cardiomyopathy (DCM). Methods: Consecutive DCM patients from two tertiary care centers, with available echocardiography at baseline and at 1-year follow-up, were retrospectively analyzed. LA dilation was defined as LAVI >34 ml/m2, change in LAVI (ΔLAVI) was defined as the 1-year relative LAVI reduction. The outcome was a composite of death/heart transplantation/heart failure hospitalization (D/HTx/HFH). Results: Five hundred sixty patients were included (age 54±13 years; left ventricular ejection fraction (LVEF) 31±10%, LAVI 45±18 ml/m2). Baseline LAVI had a non-linear association with the risk of D/HTx/HFH, independently from age, LVEF, MR and medical therapy (p<0.01). At 1-year follow-up, LAVI decreased in 374 patients (67%, median ΔLAVI -24%, interquartile range -37% - -11%). Factors independently associated with ΔLAVI were higher baseline LAVI and lower baseline LVEF. After multivariable adjustment, ΔLAVI showed a linear association with the risk of D/HTx/HFH (HR 0.96, 95% 0.93-0.99 per 5% decrease, p=0.042). At 1-year follow-up, patients with a reduction in LAVI greater than 10% and LAVI normalization (i.e. follow-up LAVI ≤34ml/m2) (31% of the overall cohort) were at lower risk of D/HTx/HFH (HR 0.37, 95% C.I. 0.35-0.97, p=0.028). Conclusions: In a large cohort of DCM, 1-year reduction in LAVI is observed in a number of patients. The association between reduction in LAVI and D/HTx/HFH suggests that LA structural reverse remodeling might be considered an additional parameter useful in the individualized risk stratification of patients with DCM.