Abstract 10549: Clinical Significances of Left Atrial Volume vs Function in Nonischemic Cardiomyopathy

Abstract

Introduction: Left atrium (LA) structure/function is reported to provide incremental prognostic information in patients with heart failure. However, its clinical impact is not fully elucidated in nonischemic cardiomyopathy (NICM). Therefore, we explored the clinical significance in patients with NICM, especially by clarifying the different roles between LA volume and emptying fraction. Methods: Consecutive patients with NICM who underwent cardiac magnetic resonance were analyzed and followed. Cox regression models were used to estimate hazard ratios (HRs) for major cardiovascular events (MACE) related to LA volume and emptying fraction. Results: Among the 625 patients with NICM including left ventricle non-compaction, dilated cardiomyopathy, hypertrophic cardiomyopathy, cardiac sarcoidosis, and cardiac amyloidosis (mean age; 64.4 ± 14.2 years, and female; 39.7%), 133 had a history of AF at baseline. Baseline AF was associated with both higher LA volume and lower emptying fraction independently; however, it was not associated with increased MACE (P = 0.245). New-onset AF developed in 5.9% of the patients during a median follow-up of 20.3 months, with maximum LA volume as its strong and independent predictor (P < 0.001, the area under the ROC curve AUC of 0.795). It was superior to LA emptying fraction (Figure A). In Kaplan-Meier analysis, patients with new-onset AF showed increased MACE compared with those of sinus rhythm or baseline AF (P = 0.002). New-onset AF and LA emptying fraction were independent predictors of MACE (HR: 2.28, 95% CI: 1.20-3.97, and HR: 0.98, 95% CI: 0.96-0.99, respectively) after adjusting for age, gender, body mass index, and diagnosis. Maximum LA volume alone was not associated with MACE (Figure B). Conclusions: Both LA volume and function were independently associated with baseline AF in patients with NICM. Maximum LA volume predicted the incidence of new-onset AF best, and only LA emptying fraction was associated with a worse prognosis.