Effect of Epicardial Fat Pad Ablation on Acute Atrial Electrical Remodeling and Inducibility of Atrial Fibrillation

Abstract

Background: Atrial electrical remodeling (AER) is the underlying mechanism of atrial fibrillation (AF). The present study investigated the impact of epicardial fat pad (FP) ablation on acute AER (AAER) and inducibility of AF. Methods and Results: AAER was performed in 28 mongrel dogs through 4-h rapid atrial pacing (RAP). Before RAP, 14 dogs (ablation group) underwent FP ablation, and the other 14 (control group) underwent a sham procedure. The atrial effective refractory period (ERP) and vulnerability window (VW) of AF were measured with and without bilateral cervical vagosympathetic nerve stimulation (VNS) at the high right atrium, ostium of the coronary sinus (CS) and distal CS before and after every hour of RAP. In the control group, ERP was markedly shortened in the first 2 h of RAP and then stabilized. AF was only slightly induced. After RAP, the time course of ERP with and without VNS was similar. VNS significantly shortened ERP and increased VW before and after RAP. In the ablation group, ERP was significantly prolonged after FP ablation. Moreover, neither VNS nor RAP shortened the ERP or increased the VW. AF could not be induced (VW=0).Conclusions: RAP resulted in AAER, which may be mediated and aggravated by autonomic activity. Epicardial FP ablation generated denervation, which not only abolishes AF inducibility but also prevents RAP-mediated AAER. (Circ J 2010; 74: 885 - 894)

Denervation as a Common Mechanism Underlying Different Pulmonary Vein Isolation Strategies for Paroxysmal Atrial Fibrillation: Evidenced by Heart Rate Variability after Ablation

“…Experimental and clinical studies have demonstrated that both sympathetic and parasympathetic components are involved in the pathogenesis of AF [16]. Increased vagal tone is associated with a shortened atrial effective refractory period and increased dispersion [3, 17], whereas sympathetic stimulation may lead to afterdepolarization and triggered firing [18], which facilitate the initiation and maintenance of AF.…”

Remodeling Induced by Atrial Fibrillation

“…7 Cardiac autonomic tonus is elevated by a brief period of AF in an accentuated sympathovagal antagonistic manner. In a canine AF model, autonomic neural remodeling is evident in the posterior LA and PV, contributing to the positive feedback mechanism that explains "AF begets AF".…”

Differential Effects of Central and Peripheral Fat Tissues on the Delayed Rectifier K⁺ Outward Currents in Cardiac Myocytes

“…Recently, obesity has also been reported to be an important risk factor for new-onset atrial fibrillation (AF) [3]. Many studies have demonstrated that the amount of pericardial fat is associated with the occurrence of AF and that catheter ablation at the pericardial fat pad can decrease the occurrence of AF [4,5,6]. An animal study also demonstrated that a high-fat diet could increase the risk of ventricular arrhythmias [7].…”