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

Background: 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. Methods: 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). Results: Patients with a FIB4 index >= 1.3 had a higher prevalence of LA LVAs (>5 cm(2)) 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. Conclusion: The FIB4 index was a novel predictor of the existence of LA LVAs on electroanatomic mapping and AF recurrence after CBA.