AUTHOR=Kuo Jen-Yuan , Jin Xuanyi , Sun Jing-Yi , Chang Sheng-Hsiung , Chi Po-Ching , Sung Kuo-Tzu , Mok Greta S. P. , Yun Chun-Ho , Chang Shun-Chuan , Chung Fa-Po , Yu Ching-Hsiang , Wu Tung-Hsin , Hung Chung-Lieh , Yeh Hung-I , Lam Carolyn S. P. 

TITLE=Insights on Distinct Left Atrial Remodeling Between Atrial Fibrillation and Heart Failure With Preserved Ejection Fraction

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.857360

DOI=10.3389/fcvm.2022.857360

ISSN=2297-055X

ABSTRACT=Background: Heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) commonly coexist with overlapping pathophysiology like left atrial (LA) remodeling, which might differ given different underlying mechanisms. 
Objectives: We sought to investigate the different patterns of LA wall remodeling in AF versus HFpEF.  
Methods: We compared LA wall characteristics including wall volume (LAWV), wall thickness (LAWT), and wall thickness heterogeneity (LAWT[SD]) and LA structure, function among the controls (without AF or HFpEF, n=115), HFpEF alone (n=59), AF alone (n=37), and HFpEF+AF (n=38) groups using multi-detector computed tomography and echocardiography. 
Results: LA wall remodeling was most predominant and peak atrial longitudinal strain (PALS) was worst in HFpEF+AF patients as compared to the rest. Despite lower E/e’(9.8±3.8 versus 13.4±6.4) yet comparable LA volume, LAWT and PALS in AF alone versus HFpEF alone, LAWV (12.6 [11.6–15.3] versus 12.0 [10.2–13.7]; p=0.01) and LAWT(SD) (0.68 [0.61–0.71] versus 0.60 [0.56–0.65]; p<0.001) were significantly greater in AF alone versus HFpEF alone even after multi-variate adjustment and propensity matching. After excluding the HFpEF+AF group, both LAWV and LAWT[SD] provided incremental values when added to PALS or LAVi (all p for net reclassification improvement <0.05) in discriminating AF alone, with LAWT[SD] yielding the largest C-statistic (0.78, 95% CI: 0.70–0.86) among all LA wall indices.
Conclusions: Despite a similar extent of LA enlargement and dysfunction in HFpEF versus AF alone, larger LAWV and LAWT[SD] can distinguish AF from HFpEF alone, suggesting the distinct underlying pathophysiological mechanism of LA remodeling in AF versus HFpEF.