The degree of left atrial structural remodeling impacts left ventricular ejection fraction in patients with atrial fibrillation

Abstract

The extent of left atrial (LA) wall structural remodeling (fibrosis) detected by late gadolinium enhancementmagnetic resonance imaging (LGE-MRI) is correlated with advanced atrial fibrillation (AF). The concomitant occurrence of AF and left ventricular (LV) dysfunction is not uncommon. We studied the effect of LA fibrosis, a confounder of both AF and LV dysfunction, on LV ejection fraction (EF). For the analysis, we identified and included 384 patients from our retrospective AF database who underwent LGE-MRI and transthoracic echocardiography prior to AF ablation. Based on the degree of LA fibrosis, patients were categorized into four stages as: Utah 1 (35% fibrosis). The average pre-ablation LVEF was 60.5%+-8.5% (n=24) in Utah stage 1 patients, 55.7%+-10.3% (n=240) in Utah stage 2 patients, 51.7+-11.5% (n=90) in Utah stage 3 patients, and 48.9%+-11.6% (n=30) in Utah stage 4 patients (p<0.001, one-way ANOVA). The percentage of LA fibrosis was significantly negatively correlated to LVEF pre-ablation in a univariate analysis (p<0.001). In a multivariate model accounting for age, gender, AF type, and comorbidities such as diabetes and hypertension, Utah stage remained a significant predictor of pre-ablation EF (p<0.001). Patients with extensive LA fibrosis appear to have depressed LV function pre-ablation, suggesting that structural remodeling in the LA may also be triggering and promoting remodeling within the ventricular myocardium.

Keywords

• atrial fibrillation/drug therapy
• catheter ablation
• heart atria; imaging
• three dimensional; magnetic resonance imaging myocardium.