Vagus nerve stimulation reverses ventricular electrophysiological changes induced by hyper-sympathetic nerve activity
Jie Huang, MD, Jin Qian, MD, Wei Yao, MD, Neng Wang, MD,* Zhenjian Zhang, MD, Chuanbin Cao, MD, Bo Song, MD, Zhuo Zhang, MD
Department of Cardiology, Suizhou Hospital, Hubei University of Medicine, Suizhou city, Hubei Province, P.R. China
Running title: Vagus nerve stimulation and ventricular electrophysiology Key
words:
autonomic
nervous
system,
vagus
nerve
stimulation,
ventricular
electrophysiology, hyper-sympathetic nerve activity Total number of words: 5, 269 Total number of references: 39 Subject area: Cardiovascular Control
* Corresponding Author: Neng Wang, MD. Department of Cardiology, Suizhou Hospital, Hubei University of Medicine, No. 60 Longmen Street, Suizhou City, Hubei Province 441300, P.R. China
E-mail: [email protected]
This is an Accepted Article that has been peer-reviewed and approved for publication in the Experimental Physiology, but has yet to undergo copy-editing and proof correction. Please cite this article as an Accepted Article; doi: 10.1113/expphysiol.2014.082842. This article is protected by copyright. All rights reserved.
1
New Findings
1. What is the central question of this study? Previous studies have shown that hyper-sympathetic nerve activity results in ventricular electrophysiological changes and facilitates the occurrence of ventricular arrhythmias. Vagus nerve stimulation has shown therapeutic potential for myocardial infarction-induced ventricular
arrhythmias.
However,
the
actions
of
vagus
nerve
stimulation
on
hyper-sympathetic nerve activity-induced ventricular electrophysiological changes are still unknown.
2. What is the main finding and its importance? We show that vagus nerve stimulation is able to reverse hyper-sympathetic nerve activity-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation. These findings further suggest that vagus nerve stimulation may be an effective treatment option for ventricular arrhythmias, especially in patients with myocardial infarction or heart failure.
This article is protected by copyright. All rights reserved.
2
Abstract Vagus nerve stimulation (VNS) has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. This study aimed to investigate the effects of VNS on ventricular electrophysiological changes induced by hyper-sympathetic nerve activity. Seventeen open-chest dogs were subjected to left stellate ganglion stimulation (LSGS) for 4 h to simulate a hyper-sympathetic tone. All animals were randomly assigned to VNS group (n=9) and control group (n=8). In VNS group, VNS was performed at the voltage causing a 10% decrease of heart rate for hours 3-4 during 4-h of LSGS. During the first 2-h of LSGS, the ventricular effective refractory period (ERP) and action potential duration (APD) were both progressively and significantly decreased; the spatial dispersion of ERP, maximum slope of restitution curve, pacing cycle length of APD alternans were all increased. With LSGS+VNS during next 2 h, there was a significant return of all the changed electrophysiological parameters toward baseline levels. In 8 control dogs that received 4-h of LSGS without VNS, all the parameters were changed progressively but without any reversals. Ventricular fibrillation threshold was higher in VNS group than that in control group (17.3±3.4V vs. 11.3±3.8V, P
Jie Huang, MD, Jin Qian, MD, Wei Yao, MD, Neng Wang, MD,* Zhenjian Zhang, MD, Chuanbin Cao, MD, Bo Song, MD, Zhuo Zhang, MD
Department of Cardiology, Suizhou Hospital, Hubei University of Medicine, Suizhou city, Hubei Province, P.R. China
Running title: Vagus nerve stimulation and ventricular electrophysiology Key
words:
autonomic
nervous
system,
vagus
nerve
stimulation,
ventricular
electrophysiology, hyper-sympathetic nerve activity Total number of words: 5, 269 Total number of references: 39 Subject area: Cardiovascular Control
* Corresponding Author: Neng Wang, MD. Department of Cardiology, Suizhou Hospital, Hubei University of Medicine, No. 60 Longmen Street, Suizhou City, Hubei Province 441300, P.R. China
E-mail: [email protected]
This is an Accepted Article that has been peer-reviewed and approved for publication in the Experimental Physiology, but has yet to undergo copy-editing and proof correction. Please cite this article as an Accepted Article; doi: 10.1113/expphysiol.2014.082842. This article is protected by copyright. All rights reserved.
1
New Findings
1. What is the central question of this study? Previous studies have shown that hyper-sympathetic nerve activity results in ventricular electrophysiological changes and facilitates the occurrence of ventricular arrhythmias. Vagus nerve stimulation has shown therapeutic potential for myocardial infarction-induced ventricular
arrhythmias.
However,
the
actions
of
vagus
nerve
stimulation
on
hyper-sympathetic nerve activity-induced ventricular electrophysiological changes are still unknown.
2. What is the main finding and its importance? We show that vagus nerve stimulation is able to reverse hyper-sympathetic nerve activity-induced ventricular electrophysiological changes and suppress the occurrence of ventricular fibrillation. These findings further suggest that vagus nerve stimulation may be an effective treatment option for ventricular arrhythmias, especially in patients with myocardial infarction or heart failure.
This article is protected by copyright. All rights reserved.
2
Abstract Vagus nerve stimulation (VNS) has shown therapeutic potential for myocardial infarction-induced ventricular arrhythmias. This study aimed to investigate the effects of VNS on ventricular electrophysiological changes induced by hyper-sympathetic nerve activity. Seventeen open-chest dogs were subjected to left stellate ganglion stimulation (LSGS) for 4 h to simulate a hyper-sympathetic tone. All animals were randomly assigned to VNS group (n=9) and control group (n=8). In VNS group, VNS was performed at the voltage causing a 10% decrease of heart rate for hours 3-4 during 4-h of LSGS. During the first 2-h of LSGS, the ventricular effective refractory period (ERP) and action potential duration (APD) were both progressively and significantly decreased; the spatial dispersion of ERP, maximum slope of restitution curve, pacing cycle length of APD alternans were all increased. With LSGS+VNS during next 2 h, there was a significant return of all the changed electrophysiological parameters toward baseline levels. In 8 control dogs that received 4-h of LSGS without VNS, all the parameters were changed progressively but without any reversals. Ventricular fibrillation threshold was higher in VNS group than that in control group (17.3±3.4V vs. 11.3±3.8V, P
