Left and right atrial echocardiographic parameters and outcome in patients with atrial fibrillation

Background: This study evaluates the association between left and right atrial (LA, RA) parameters and a composite endpoint (CEP) of all-cause death, thromboembolism, acute coronary syndrome, and heart failure hospitalization in atrial fibrillation patients. Methods: Patients were prospectively enrolled. At baseline, the following echocardiogram parameters were measured: LA and RA antero-posterior diameter indexed (iLAAPD, iRAAPD), LA and RA volume indexed (LAVi, RAVi), LA and RA sphericity index (LASI, RASI), LA and RA emptying fraction. Results: A total of 489 patients (61.3% males) with a median age of 75 (66-80) years and a median CHA2DS2VASc score of 3 (2-5) were enrolled (92.2% receiving anticoagulation). Permanent atrial fibrillation was present in 40.5% of the total cohort. After a median follow-up of 1114 (392-1384) days, 129 patients (26.3%) reached the CEP. The highest sensitivity for CEP was for LA emptying fraction <28% and iRAAPD >24 mm/m2 (72% and 73%, respectively) while the best negative predictive values were for iLAAPD and LAVi (both 81%). Right atrial parameters were not associated with CEP. Discrimination analysis using net reclassification improvement (NRI) showed that iLAAPD, and LAVi significantly improved patient reclassification compared to a null model without atrial parameters (iLAAPD NRI 0.30; P = 0.005; LAVi NRI 0.32; P = 0.002). Multivariable Cox regression analysis found that LA dimensions, volume, and function were associated with a higher risk of adverse outcomes and significantly improved risk prediction for the CEP. Conclusions: LAVi and iLAAPD enhance discrimination and risk prediction for adverse outcomes in AF patients.