Associations of the fibrosis‐4 index with left atrial low‐voltage areas and arrhythmia recurrence after catheter ablation: cardio‐hepatic interaction in patients with atrial fibrillation

The relationship between liver fibrosis and left atrial (LA) remodeling in atrial fibrillation (AF) remains uncertain. We examined the associations between the fibrosis‐4 (FIB4) index, an indicator of liver fibrosis, and both LA low‐voltage areas (LVAs) on electroanatomic mapping and AF recurrence postablation. We recruited 343 patients who underwent radiofrequency catheter ablation (RFCA) or cryoballoon ablation (CBA) for AF. First, the association between the FIB4 index and LA LVAs (<0.5 mV) was evaluated in RFCA using electroanatomic mapping (n= 214). Next, the utility of a FIB4 index ≥1.3, recommended cut‐off value of liver fibrosis, was verified to assess the risk for AF recurrence in CBA without additional LVA ablation (n= 129). Patients with a FIB4 index ≥1.3 had a higher prevalence of LA LVAs (>5 cm2) compared to those without. Additionally, the quantitative size of LVAs showed a positive correlation with the FIB4 index (R= .642, p< .001). In multivariate logistic models, a FIB4 index ≥1.3 was related to the presence of LVAs after adjusting for LA diameter, right atrial end‐systolic area, and nonparoxysmal AF (odds ratio 2.508; p= 0.039). In CBA, AF recurrence rate was 13.1% during 3–12 months postablation. In multivariate Cox models, a FIB4 index ≥1.3 was an important predictor of AF recurrence (hazard ratio 3.796; p= .037), suggesting that LVAs might be associated with AF recurrence after CBA. The FIB4 index was a novel predictor of the existence of LA LVAs on electroanatomic mapping and AF recurrence after CBA. We investigated the associations between the fibrosis‐4 (FIB4) index, an indicator of liver fibrosis, and both left atrial (LA) low‐voltage areas (LVAs) on electroanatomic mapping and atrial fibrillation (AF) recurrence postablation. Our study results suggest that the FIB4 index is a predictor of the presence of LVAs and AF recurrence.