Liang Xiong1,2,3, Yu Liu1,2,3, Mingmin Zhou1,2,3, Guangji Wang1,2,3, Dajun Quan1,2,3, Caijie Shen1,2,3, Wei Shuai1,2,3, Bin Kong1,2,3, Congxin Huang1,2,3, He Huang1,2,3. 1. Department of Cardiology, Renmin Hospital of Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China. 2. Cardiovascular Research Institute, Wuhan University, No.238 Jiefang Road, Wuchang, Wuhan, China. 3. Hubei Key Laboratory of Cardiology, No.238 Jiefang Road, Wuchang, Wuhan, China.
Abstract
Aims: The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI). Methods and results: Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Five weeks after surgery, the cardiac function, heart rate variability (HRV), ventricular electrophysiological parameters, LSG function and neural activity, serum norepinephrine (NE), nerve growth factor (NGF), and brain natriuretic peptide (BNP) levels were measured. Cardiac sympathetic innervation was determined with immunofluorescence staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Compared with MI group, TACSN significantly improved HRV, attenuated LSG function and activity, prolonged corrected QT interval, decreased Tpeak-Tend interval, prolonged ventricular effective refractory period (ERP), and action potential duration (APD), decreased the slopes of APD restitution curves, suppressed the APD alternans, increased ventricular fibrillation threshold, and reduced serum NE, NGF, and BNP levels. Moreover, the densities of GAP43 and TH-positive nerve fibres in the infarcted border zone in the MI-TACSN group were lower than those in the MI group. Conclusion: Targeted ablation of cardiac sympathetic neuron attenuates sympathetic remodelling and improves ventricular electrical remodelling in the chronic phase of MI. These data suggest that TACSN may be a novel approach to treating ventricular arrhythmias.
Aims: The purpose of this study was to evaluate the cardiac electrophysiologic effects of targeted ablation of cardiac sympathetic neurons (TACSN) in a canine model of chronic myocardial infarction (MI). Methods and results: Thirty-eight anaesthetized dogs were randomly assigned into the sham-operated, MI, and MI-TACSN groups, respectively. Myocardial infarction-targeted ablation of cardiac sympathetic neuron was induced by injecting cholera toxin B subunit-saporin compound in the left stellate ganglion (LSG). Five weeks after surgery, the cardiac function, heart rate variability (HRV), ventricular electrophysiological parameters, LSG function and neural activity, serum norepinephrine (NE), nerve growth factor (NGF), and brain natriuretic peptide (BNP) levels were measured. Cardiac sympathetic innervation was determined with immunofluorescence staining of growth associated protein-43 (GAP43) and tyrosine hydroxylase (TH). Compared with MI group, TACSN significantly improved HRV, attenuated LSG function and activity, prolonged corrected QT interval, decreased Tpeak-Tend interval, prolonged ventricular effective refractory period (ERP), and action potential duration (APD), decreased the slopes of APD restitution curves, suppressed the APD alternans, increased ventricular fibrillation threshold, and reduced serum NE, NGF, and BNP levels. Moreover, the densities of GAP43 and TH-positive nerve fibres in the infarcted border zone in the MI-TACSN group were lower than those in the MI group. Conclusion: Targeted ablation of cardiac sympathetic neuron attenuates sympathetic remodelling and improves ventricular electrical remodelling in the chronic phase of MI. These data suggest that TACSN may be a novel approach to treating ventricular arrhythmias.