Epicardial ganglionated plexi ablation increases the inducibility of ventricular tachyarrhythmias in a canine postmyocardial infarction model. Wu Bing,Xu Shanghua,Dai Ruozhu,Hong Meiman,Wu Haiyun,Lin Rong Journal of cardiovascular electrophysiology INTRODUCTION:Previous studies have shown that epicardial ganglionated plexi ablation (EGPA) could increase the risk of ventricular arrhythmias induced by acute myocardial ischemia. However, the long-term effect of EGPA in a canine postmyocardial infarction (MI) model is not well established. MATERIALS AND METHODS:Twenty mongrel dogs were randomly divided into two groups: an MI group (n = 10) and an EGPA group (EGPA plus MI, n = 10). EGPA was achieved by ablation of four major ganglion plexi and the ligament of Marshall. The electrocardiograph (ECG) parameters, ventricular effective refractory period (ERP), inducibility of tachyarrhythmias, and ventricular fibrillation threshold (VFT) were measured at baseline and after 8 weeks. Tyrosine hydroxylase (TH) and nerve growth factor (NGF) expression levels in the peri-infarcted zone were also determined by immunohistochemistry in both groups at the end of the study. RESULTS:No significant differences were found in electrophysiological parameters at the baseline between the two groups. At the end of the 8-week follow-up, however, the EGPA group was associated with a longer QT interval, corrected QT (QTc) interval and ventricular ERP, larger dispersion of QT, QTc, and ERP, and higher inducibility of tachyarrhythmia and VFT when compared to the MI group. In addition, the density of TH and NGF in the peri-infarcted zone was also significantly increased in the EGPA group in comparison to the MI group. CONCLUSIONS:After the 8-week follow-up, EGPA increased the ventricular arrhythmia inducibility in the canine post-MI model, likely by increasing ventricular electrophysiological instability and promoting ventricular sympathetic remodeling. 10.1111/jce.13912

Ablation of epicardial ganglionated plexi increases atrial vulnerability to arrhythmias in dogs. Mao Jun,Yin Xiandong,Zhang Ying,Yan Qian,Dong Jianzeng,Ma Changsheng,Liu Xingpeng Circulation. Arrhythmia and electrophysiology BACKGROUND:Previous studies have suggested that systematic ablation of ganglionated plexi (GP) could increase the short-term success rate of radiofrequency ablation for atrial fibrillation, but the long-term efficacy of this approach is not fully established. METHODS AND RESULTS:Twenty-four mongrel dogs were divided into 3 groups: epicardial GP ablation group 1 (n=8), epicardial GP ablation group 2 (n=8), and a sham operation group (n=8). In the 2 epicardial GP ablation groups, the 4 major GP and the ligament of Marshall were systematically ablated. The effective refractory period and inducibility of tachyarrhythmias were measured before and immediately after GP ablation in epicardial GP ablation group 1 and 8 weeks later in the other 2 groups. Tyrosine hydroxylase and choline acetyltransferase expressions were also determined immunohistochemically 8 weeks later in the latter groups. Compared with epicardial GP ablation group 1 and the sham operation group, epicardial GP ablation group 2 had the shortest atrial and ventricular effective refractory period and the highest inducibility of atrial tachyarrhythmias. The inducibility of ventricular tachyarrhythmias among the 3 groups was comparable. The density of tyrosine hydroxylase- and choline acetyltransferase-positive nerves in the atrium was the highest in epicardial GP group 2, whereas there were no significant intergroup differences in the densities of these 2 types of nerves in the ventricle. CONCLUSIONS:After 8 weeks of healing, epicardial GP ablation without additional atrial ablation was potentially proarrhythmic, which may be attributable to decreased atrial effective refractory period and hyper-reinnervation involving both sympathetic and parasympathetic nerves. 10.1161/CIRCEP.113.000799

Study of the Distribution of Epicardial Vagal Ganglion and the Relationship Between Delayed Enhancement Magnetic Resonance Imaging and Radiofrequency Ablation in Patients with Atrial Fibrillation. Zhou Wei,Chen Jiulin,Chen Jingjing,Wang Long,Li Yongkang,Deng Na,Tang Qian,Wu Lirong,Zhou Bo,Li Wei World neurosurgery This article presents a retrospective study of patients undergoing radiofrequency ablation of atrial fibrillation (AF); analyzes the characteristics of heart rate variability (HRV) in patients; and explores the role of delayed enhancement magnetic resonance imaging and autonomic nervous system function, changes in autonomic nervous system function, and recurrence of AF after radiofrequency ablation to understand the effect of denervation of the autonomic nervous system on the efficacy of radiofrequency ablation of AF. The study found that there were no significant differences in clinical baseline characteristics, mean heart rate, and HRV indicators between patients without relapse and patients with relapse (P > 0.05). The overall HRV index was significantly reduced after surgery as well as before surgery. In the relapse-free group, the high-frequency power that responded to vagal tone was more significant, the low-frequency/high-frequency power ratio increased, and other HRV indicators were significantly reduced; in the relapse group, mean heart rate increased, sympathetic response to the low-frequency power of nerve tension was significantly reduced, and the low-frequency/high-frequency power ratio was decreased. The difference was statistically significant (P < 0.05). Therefore, sympathetic and parasympathetic nerve function were significantly reduced after radiofrequency ablation of the pulmonary veins in patients with AF. Reducing vagus nerve tension may inhibit early recurrence of paroxysmal AF in patients after left atrial ring pulmonary vein ablation. 10.1016/j.wneu.2020.01.007

Electroporation of epicardial autonomic ganglia: Safety and efficacy in medium-term canine models. Padmanabhan Deepak,Naksuk Niyada,Killu Ammar K,Kapa Suraj,Witt Chance,Sugrue Alan,DeSimone Christopher V,Madhavan Malini,de Groot J R,O'Brien Barry,Rabbette Tadhg,Coffey Kenneth,Asirvatham Samuel J Journal of cardiovascular electrophysiology BACKGROUND:Endocardial radiofrequency ablation of epicardial ganglionic plexus (GP) for atrial fibrillation (AF) is complicated by myocardial damage. OBJECTIVES:We hypothesized that an epicardial approach with a novel nitinol catheter system capable of causing irreversible electroporation (IRE) with direct current (DC) could selectively and permanently destroy GP without collateral myocardial injury. METHODS:Acute studies and medium-term terminal studies (mean survival, 1137 days) were performed with seven dogs. In the acute studies, DC was used to target epicardial GP within the transverse sinus, oblique sinus, vein of Marshall, and right periaortic space. Successful electroporation was defined as the presence of ablative lesions in the GP without collateral myocardial damage. A four-point integer system was used to classify histologic changes in tissue harvested from the ablation sites. Atrial effective refractory period (AERP) was measured during the acute and medium-term studies. RESULTS:For six dogs in the medium-term studies, the postablation period was uneventful without complications. Lesions were successfully created at 20 of 21 sites (95.2%) with more than minimal myocardial damage in one dog. An increase in AERP occurred in both atria during the acute studies but was maintained only in the right atrium at medium-term follow-up (5032 milliseconds). No dog had damage to the esophagus, adjacent great arteries, or pulmonary veins. CONCLUSIONS:This proof-of-concept study suggests that safe, effective, and selective epicardial ablation of GP can be performed with DC by IRE with minimal collateral myocardial damage. 10.1111/jce.13860