Atrial Structural Remodeling in Patients With Atrial Fibrillation Is a Diffuse Fibrotic Process: Evidence From High‐Density Voltage Mapping and Atrial Biopsy

Abstract

Background Low‐voltage areas (LVAs) in the atria of patients with atrial fibrillation are considered local fibrosis. We hypothesized that voltage reduction in the atria is a diffuse process associated with fibrosis and that the presence of LVAs reflects a global voltage reduction. Methods and Results We examined 140 patients with atrial fibrillation and 13 patients with a left accessory pathway (controls). High‐density bipolar voltage mapping was performed using a grid‐mapping catheter during high right atrial pacing. Global left atrial (LA) voltage (V GLA ) in the whole LA and regional LA voltage (V RLA ) in 6 anatomic regions were evaluated with the mean of the highest voltage at a sampling density of 1 cm 2 . Patients with atrial fibrillation were categorized into quartiles by V GLA . LVAs were evaluated at voltage cutoffs of 0.1, 0.5, 1.0, and 1.5 mV. Twenty‐eight patients with atrial fibrillation also underwent right atrial septum biopsy, and the fibrosis extent was quantified. Voltage at the biopsy site (V biopsy ) was recorded. V GLA results by category were Q1 (<4.2 mV), Q2 (4.2–5.6 mV), Q3 (5.7–7.0 mV), and Q4 (≥7.1 mV). V RLA at any region was reduced as V GLA decreased. V GLA and V RLA did not differ between Q4 and controls. The presence of LVAs increased as V GLA decreased at any voltage cutoff. Biopsies revealed 11±6% fibrosis, which was inversely correlated with both V biopsy and V GLA ( r =–0.71 and –0.72, respectively). V biopsy was correlated with V GLA ( r =0.82). Conclusions Voltage reduction in the LA is a diffuse process associated with fibrosis. Presence of LVAs reflects diffuse voltage reduction of the LA.

High liver fibrosis scores in metabolic dysfunction-associated fatty liver disease patients are associated with adverse atrial remodeling and atrial fibrillation recurrence following catheter ablation

“…fibrosis” and “MAFLD w/o fibrosis”) did not display any significant difference regarding low-voltage area compared to “noMAFLD” patients. Since low-voltage zones have been associated with local fibrosis ( 30 ), which may impact LA hemodynamics, we explored the LA reservoir and contractile function assessed by four-chamber LA 2D-speckle tracking in patients presenting sinus rhythm prior to AF ablation.…”

Isolated Atrial Fibrillation, Inflammation and Efficacy of Radiofrequency Ablation: Preliminary Insights Based on a Single-Center Endomyocardial Biopsy Study

“…At the end of the article, the authors concluded that factors other than fibrosis could affect voltage, e.g., myocyte cell size, myocyte disarray, intercellular-spacing, myofibrillar loss, infiltration with adipocytes. However, the impacts of these factors on voltage have not been analyzed, and future studies are warranted [ 15 ]. In our study, we conducted endocardial biopsies from IAS with the transesophageal ECHO control.…”

Low left atrial voltage predicts lack of improvement in left ventricular systolic function post atrial fibrillation ablation in patients with systolic heart failure.

“…In our study population, LVEF significantly improved by 17+-11.8% after CA of AF, which was consistent with 8% to 18% improvement in LVEF after CA in patients with HFrEF observed in randomized controlled trials 1,4 . Low LA endocardial bipolar voltage measured during CA for AF, is a commonly used surrogate marker for the presence of LA fibrosis, a common pathological feature of AF 5 . Several studies have demonstrated benefits of voltage guided ablation in improving arrhythmia free survival following CA 6,7 .…”