{"paper_id":"041171ad-d90f-4f0b-85ae-674c1eddb8b9","body_text":"Effects of different intensity of atrial pacing on atrial electrophysiology and nerve remodeling | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effects of different intensity of atrial pacing on atrial electrophysiology and nerve remodeling Zhi Yang, Jianing Fan, Wenjing Xue, Fuhua Lei, Feng Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2765190/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background and Objective Atrial fibrillation (AF) could be induced by different intensity of atrial pacing, however the detail information during these processes have not been fully explored. The aim of this study was to evaluate the effects of different intensity of atrial pacing on atrial electrophysiology. Methods Twenty-four dogs were randomly subjected to 16 hours atrial pacing at 500 beats/min (bpm) or 1000 bpm as follows: no stimulation (control, n = 8), 500 bpm stimulation (500 bpm, n = 8) and 1000 bpm stimulation (1000 bpm, n = 8). Programmed and burst atrial pacing were performed at baseline and at the end of every 2 hour to determine AF inducibility, sustained time of AF and atrial effective refractory period (ERP). Moreover, the electrical activities of vagus nerve including discharge frequency, signal area were also recorded. In addition, serum acetylcholine (Ach) was determined by ELISA to explore the relationship with AF and vagus nerve features. Results Increased AF inducibility, sustained time of AF and ERP were found in dogs from 1000 bpm group compared to 500 bpm group. Moreover, increased discharge frequency and signal area of vagus nerve were also found in dogs from 1000 bpm group compared to 500 bpm group. Correlation was found between the serum Ach and AF. Conclusions Our results demonstrated that different intensity of atrial pacing exerted different effects on atrial electrophysiology and nerve remodeling, while high-frequency electrical stimulation are more prone to autonomic nervous activity induction. Atrial fibrillation autonomic nervous system vagus nerve nerve electrical signaling acetylcholine Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction Atrial fibrillation (AF) is a highly prevalent disease associated with pronounced morbidity and mortality [ 1 ]. Despite the availability of numerous therapeutic agents, the available treatments have significant limitations[ 2 , 3 ] and AF continues to be a clinical challenge. Accumulating evidence has demonstrated that cardiac autonomic nerve remodeling (ANR), characterized by nerve regeneration, as well as by uneven distribution of the sympathetic and vagus nerves, is involved in the pathogenesis of both acute and chronic AF [ 4 , 5 ], and emerging evidence on autonomic modulation underscores its use as a novel treatment modality for AF[ 6 , 7 ]. Moreover, rapid atrial pacing (RAP) could decrease the atrial effective refractory period, slow atrial conduction, and increase electrophysiologic heterogeneity [ 8 – 10 ], thereby resulting in AF. However, no study compared the extract electrophysiological data and nerve eletrical signaling data in AF in the setting of different intensity of RAP. In present study, we employed a pair of unipolar electrodes to insert into the vagal trunk and recorded the nerve electrical signaling to elucidate the relationship between atrial pacing induced AF and features of nerve electrical signaling. Moreover, we also detected the electrophysiology data and serum acetylcholine level to evaluate the effects of vagus nerve. The data obtained here will provide nerve electrical basic information about the AF and autonomic nerve system. Materials And Methods Ethical approval of the study protocol The study protocol was approved by the Institutional Animal Care and Use Committee of the First Affiliated Hospital of Xinjiang Medical University, Uyghur city, Xinjiang Uyghur Autonomous Region, China. The study was conducted following international guidelines for animal experimentation. Animal and grouping Twenty-four male adult beagle dogs weighing 10–15 kg provided by animal science center of Xinjiang Medical University were used in this study. Animals were randomly divided into control group (no stimulation, n = 8), 500 bpm rapid atrial pacing (RAP) stimulation group (500 bpm group, n = 8) and 1000 bpm rapid atrial pacing stimulation group (1000 bpm, n = 8). Animal preparation All the animals were fasting for food for 12 h and for drinking for 6 h. General anesthesia was induced with Ketamine 20 mg/kg and maintained with 3% sodium pentobarbital. Standard electrocardiography and pulse oximeter oxygen saturation were continuously monitored. Right femoral arteries and veins were cannulated and used for catheter insertion and blood pressure recording. The standard electrocardiographic lead II and blood pressure were continuously monitored using a pressure transducer. The right external jugular vein was cannulated and used for catheter insertion into the right atrium (RA) to record right atrial potentials and to perform RAP.A left-sided thoracotomy was performed at the fourth intercostal space. Multielectrode catheters were sutured to the left atrial appendage (LAA), left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV)[ 11 ]. Nerve signaling recording and analysis The right cervical vagal trunk was exposed by dissection, and a pair of unipolar electrodes (Streamline temporary myocardial pacing lead, Me-dtronic, Fridley, MN, USA) was inserted into the vagal trunk for RAP stimulation group. After signaling noise ratio(SNR) > 2.5 and stable, electrogram was recorded using LabChart 7 (AD Instruments, Colorado Springs, CO, USA) with filter setting of 50 to 200 Hz. Discharge frequency, amplitude and peak area score were recorded every 2 h after RAP stimulation, and analysis was performed using any 300 s nerve signaling figures during each time point. RAP and electrophysiology Unilateral electrical stimulation of the RAP at 500 beats/min (bpm) and 1000 bpm for 16 h were used to establish a canine model of AF. Before pacing and stimulation, the baseline electrophysiological data of AF inducibility, AF duration, effective refractory period (ERP) and dispersion of ERP (dERP) were measured. AF was defined as an irregular atrial rate > 450–600 beats/min and a duration > 5 s associated with irregular atrioventricular conduction [ 12 ]. AF inducibility rate was defined as successful AF times/total induction times. After pacing every 2 h, RAP stimulation was temporarily discontinued to obtain the electrophysiological data. Continuous RAP (500 or 1000 bpm, 0.5 ms, twice-threshold current) was administered to different groups of dogs at the RA for 16 h. Programmed stimulation at atrial sites or pulmonary vein sleeves was performed using a programmable cardiac stimulator (Lead-2000 EP Control, Sichuan Jinjiang, China). ERP was defined as the longest S1–S2 interval that failed to produce a response. ERP was measured at an atrial pacing cycle length of 300 ms, and the S1–S2 intervals were decreased from 200 ms by increments of 5 ms until no response was observed (S1:S2 = 8:1, twice-threshold current, 0.5 ms in duration). dERP was defined as the coefficient of variation (SD/mean) of the ERP at all four sites (LSPV, LIPV, LAA and RA). Immunohistochemical analysis After the electrophysiological study, ventricular fibrillation was induced by 9 V DC current to sacrifice the animals. Tissues were obtained from both atrial free walls. Immunohistochemical staining was performed for tyrosine hydroxylase (anti-TH antibody, Accurate Chemical & Scientific Corporation, Westbury, NY, USA) and Choline Acetyltransferase (anti-CHAT antibody, Chemicon International Inc., Billerica, MA, USA) using the protocols described elsewhere [ 13 ]. Five high power fields from each slide, were randomly chosen and nerve density (anti-TH) or nerve sprouting (anti-CHAT) was automatically determined by the computerized detection of the stained brown color (Image-Pro 4.0). Serum acetylcholine (Ach) determination Venous blood was collected into anticoagulant tubes before and every 2 h after pacing and stimulation. Serum were isolated by 3000 rpm centrifugation for 15 min and stored in -80°C before further experimentation. Serum Ach level were determined by an ELISA kit according to manufacturer’s instructions. Statistical analysis All the statistical analyses were performed using SPSS software version 19.0 (SPSS Inc., Chicago, IL, USA). Measurement data are expressed as mean ± SD. Qualitative data are expressed as ratios. Values between the two groups were compared using paired t tests, and comparisons among multiple groups were made using ANOVA. ANOVA for repeated measures was used to compare the changes at different times during pacing and stimulation. The χ 2 test was used to compare qualitative data; P < 0.05 was considered to be statistically significant. Results Effects of burst atrial pacing on the blood pressure and heart rates Atrial electrical stimulation could result 10–20% increasing of blood pressure and 10–20% increasing of heart rates compared to the baseline condition, which is persisting until the end of experiment (Fig. 1 ). Effects of different frequency atrial pacing on AF sustained time, AF inducibility rate, ERP and dERP In order to evaluate the effects of different frequency atrial pacing on atrial electrophysiology, we firstly measured AF sustained time, AF inducibility rate, ERP and dERP under different frequency of electrical stimulation. As shown in Fig. 2 , no significant difference was found at pre-stimulation on AF sustained time, AF inducibility rate, ERP and dERP between 1000 bpm and 500 bpm groups. Decreased ERP was found in 1000 bmp group compared to 500 bpm group and statistically significances were found at 2, 4, 6 and 8 hrs time points (all p < 0.05). Significant increased AF sustained time were found at all time points in dogs from 1000 bpm group compared to 500 bpm group (all p < 0.05). Furthermore, increased AF inducibility rates were found in 1000 bmp group compared to 500 bpm group and significantly increased percentages of 20.0%, 17.2%, 25.7%, 14.3%, 11.4% and 11.4% were respectively found at 2, 4, 6, 8, 10 and 12 h time points (all p < 0.05). In addition, significantly increased dERPs were found at 2 and 4 h time points in 1000 bmp group compared to 500 bpm group (all p < 0.05). Effects of different frequency atrial pacing on nerual remodeling After 12 hours RAP, the nerve density of the atrium represented as the area positive for ChAT staining was significantly increased in 1000 bpm group compared to that in 500 bpm group (Fig.3). Effects of different frequency atrial pacing on discharge frequency and signal area of vagus nerve Then we determined the effects of different frequency atrial pacing on discharge frequency and signal area of vagus nerve, the results were shown in Fig. 4. The discharge frequency in 500 bpm group and 1000 bpm group at 0, 2, 4, 6, 8, 10, 12, 14 and 16 h were respectively 59, 81, 92, 129, 115, 106, 110, 100, 90 times and 58, 81, 133, 109, 106, 109, 95, 90, 92 times, and significant differences were found at 2, 4 and 6 h time points (all P < 0.05). Moreover, signaling area in 500 bpm group and 1000 bpm group at 0, 2, 4, 6, 8, 10, 12, 14 and 16 h were respectively 4.35µv.s, 69.61µv.s, 53.35µv.s, 35.18µv.s, 18.96µv.s, 16.90µv.s, 11.30µv.s, 14.13µv.s, 16.81µv.s and 6.70µv.s, 77.66µv.s, 94.65µv.s, 10.43µv.s, 17.07µv.s, 12.56µv.s, 33.87µv.s, 28.30µv.s, 12.30µv.s, and significant differences were found at 2, 4, 6 and 8 h time points (all P < 0.05). In addition, we also recorded the typical nerve activity feature curves under different atrial pacing stimulation, which were shown in Fig. 5 . Effects of different frequency atrial pacing on serum Ach Furthermore, we also determined the effects of different frequency atrial pacing on serum Ach and the results were shown in Fig. 6 and Table.1. Significant differences were found at 2, 4 and 8 h time points in 1000 bpm group compared to 500 bpm group (all P < 0.05). Table 1 Serum acetylcholine at different time points between 500 bpm and 1000 bpm groups Time post stimulation Groups 500 bpm group 1000 bpm group 0 h 57.921 ± 7.945 57.425 ± 4.225 2 h 52.535 ± 7.329 67.737 ± 5.823 4 h 43.839 ± 7.784 78.170 ± 6.316 6 h 53.995 ± 6.955 62.805 ± 4.681 8 h 64.850 ± 5.391 52.945 ± 5.014 10 h 58.743 ± 5.225 60.405 ± 4.703 12 h 57.383 ± 9.676 62.473 ± 3.671 14 h 56.783 ± 8.831 63.531 ± 4.832 16 h 54.431 ± 6.921 57.984 ± 4.921 Discussion RAP stimulation could result in tension change of autonomic nerve system and increased atrial pacing, atrial nerve and electrical remodeling, and autonomic imbalance contributes to the initiation and maintenance of AF [ 14 ]. In present study, we found that significantly increased AF inducibility rate and sustained time in 1000 bpm group compared to 500 bpm group, however, no difference was found on the heart rates between these 2 groups. According to the electrophysiology features of cardiomyocytes, stimulation at resting could induce cardiac electrical excitation, whereas high frequency stimulation during ERP could only activate autonomic nerve but not myocardial electrical activity[ 15 , 16 ]. Therefore, synchronous recording of vagus nerve stimulation could be achieved during high frequency stimulation, which could be helpful for exploration of the relationship between vagus nerve and AF. The Intrinsic Cardiac Nervous System (ICNS) and the Extrinsic Cardiac Nervous System (ECNS) constitute jointly the human cardiac nervous system. The ICNS in turn consists of interconnected groups of ganglia with axons and ganglionated plexi (GP) concentrated within the epicardial fat pad, which plays a functionally complex regulatory role.[ 17 , 18 ]. These GPs may serve to incorporate autonomic signals and regulate the complicated relationship between ICNS and ECNS. Many authors have obtained heart rate variability (HRV) by calculating changes in the RR interval of the ECG signal in order to assess cardiac autonomic activity in a non-invasive manner. These variations are computed in the time- and frequency-domain; in the last case they are expressed as sinusoidal power values (power spectrum). Usually a decrease in sympathetic tone an increase in vagal tone can cause high HRV [ 19 ]. Great controversy exists in the absolute and relative variations of the power spectrum components related to sympathetic and parasympathetic modulation provoked by aerobic training [ 20 , 21 ]. Zhou et al[ 19 ] demonstrated that the combination of unilateral electrical stimulation of the stellate ganglion (SG) with RAP enables the construction of a successful canine model of acute AF mediated by excess sympathetic activity. SG stimulation promoted the induction of atrial fibrillation and exacerbated electrical remodeling in the atrium and pulmonary vein sites. Unilateral stellate ganglionectomy inhibits sympathetic activation and reduces the occurrence of atrial fibrillation. This effect was achieved by suppressing the induction of AF and electrical remodeling at the atrial and pulmonary vein sites produced by SG activation. Jung et al[ 20 ] used Data Sciences International (DSI) transmitters to make continuous 24-h signal recordings of neural activity of SG in normally ambulatory dogs for an average of 41.5 ± 16.6 days. The results showed a circadian variation of sympathetic outflow. Both basic and clinical evidence suggests that, with regard to effects of ICANS, stimulation of GP promotes the development and maintenance of AF, with a significant decrease in the recurrence of AF in the correlated structures after transcatheter or surgical ablation of GP [ 21 ]. However, all these evidences only suggested possible association between CANS and AF, but not provide the quantitative data of nerve electrical signaling. Here, the right cervical vagal trunk was exposed by dissection, and a pair of unipolar electrodes was inserted into the vagal trunk for RAP stimulation group. We found that increased discharge frequency and signal area of vagus nerve were also found in dogs from 1000 bpm group compared to 500 bpm group. These results suggested that different degree of atrial and cardiac nerve remodeling could be generated by different atrial pacing, and high CANS activity could be achieved by high frequency stimulation. These results also consistent with the results that high frequency stimulation during ERP could only activate autonomic nerve but not myocardial electrical activity. Ach, the main vagal neurotransmitter, could shorten ERP and action potential and prolong the effects of dERP, which is critical for initiation and maintenance of AF[ 22 ]. According to the results obtained here, no significant changes were found on Ach level between 1000 bpm group and 500 bpm group, and both groups showed increased and time dependent manner of Ach level, which is consistent with nerve electrical features. The results of Ach obtained here suggested that initiation and maintenance of AF was closely related with nerve activation in 1000 bpm group, whereas atrial remodeling played a key role in 500 bpm group. In conclusion, we demonstrated here the association between nerve electrical activity of autonomic nervous system and atrial remodeling in AF, which might be a better target for employment of vagus nerve for the therapeutic purpose of AF. Further exploration the relationship between autonomic nervous system and AF could be helpful to understand the role of vagus nerve electrical activity on the initiation, maintain and refractory of the AF, which might be of clinical significance for decreasing the prevention and treatment of AF. Declarations Ethical Approval Consent to Participate: This study was in accordance with the Declaration of Helsinki and ARRIVE guidelines. The study protocol was approved by the Institutional Animal Care and Use Committee of the First Affiliated Hospital of Xinjiang Medical University, Uyghur city, Xinjiang Uyghur Autonomous Region, China. Conflict of interest: none declared. Consent for Publication: Not applicable. Authors’ Contributors: Zhi Yang and Jianing Fan wrote the main manuscript text and Wenjing Xue ,Fuhua Lei, Feng Zhang prepared figures. All authors reviewed the manuscript. Funding: This research was supported by Fudan University Youth Research Fund(Grant No: JYQN-JC-202010). The funder has designed this study and decided to publish this manuscript. Acknowledgment: We thank Institutional Animal Experiment Center of the First Affiliated Hospital of Xinjiang Medical University for providing laboratories to ensure successful conduct of experiments. Availability of data and materials : The data that support the findings of this study are available on request from the corresponding author, [Feng Zhang]，upon reasonable request. Competing Interests: The authors have declared that no competing interests exist. References Zhang, Y., et al., MicroRNA profiling of atrial fibrillation in canines: miR-206 modulates intrinsic cardiac autonomic nerve remodeling by regulating SOD1. PLoS One, 2015. 10 (3): p. e0122674. Gillinov, A.M., et al., Rate control versus rhythm control for atrial fibrillation after cardiac surgery. New England Journal of Medicine, 2016. 374 (20): p. 1911-1921. Nattel, S. and D. Dobrev, Controversies about atrial fibrillation mechanisms: aiming for order in chaos and whether it matters. Circulation research, 2017. 120 (9): p. 1396-1398. Chang, C.M., et al., Nerve sprouting and sympathetic hyperinnervation in a canine model of atrial fibrillation produced by prolonged right atrial pacing. Circulation, 2001. 103 (1): p. 22-5. Yu, F.S., et al., [Nerve remodeling in a canine model of atrial fibrillation induced by 48 hours right atrial pacing]. Zhonghua Xin Xue Guan Bing Za Zhi, 2010. 38 (7): p. 644-7. Oh, S., et al., Vagal denervation and atrial fibrillation inducibility: epicardial fat pad ablation does not have long-term effects. Heart Rhythm, 2006. 3 (6): p. 701-8. Shen, M.J., et al., Continuous low-level vagus nerve stimulation reduces stellate ganglion nerve activity and paroxysmal atrial tachyarrhythmias in ambulatory canines. Circulation, 2011. 123 (20): p. 2204-12. Saengklub, N., et al., Dronedarone attenuates the duration of atrial fibrillation in a dog model of sustained atrial fibrillation. Exp Anim, 2017. 66 (3): p. 251-258. Kijtawornrat, A., B.M. Roche, and R.L. Hamlin, A canine model of sustained atrial fibrillation induced by rapid atrial pacing and phenylephrine. Comp Med, 2008. 58 (5): p. 490-3. Ashikaga, K., et al., Effects of amiodarone on electrical and structural remodeling induced in a canine rapid pacing-induced persistent atrial fibrillation model. Eur J Pharmacol, 2006. 536 (1-2): p. 148-53. Liu, F., et al., Low-Level Stimulation and Ethanol Ablation of the Vein of Marshall Prevent the Vagal-Mediated AF. Front Cardiovasc Med, 2021. 8 : p. 675485. Lu, Z., et al., Atrial fibrillation begets atrial fibrillation: autonomic mechanism for atrial electrical remodeling induced by short-term rapid atrial pacing. Circ Arrhythm Electrophysiol, 2008. 1 (3): p. 184-92. Cao, J.M., et al., Relationship between regional cardiac hyperinnervation and ventricular arrhythmia. Circulation, 2000. 101 (16): p. 1960-9. Chen, P.S., et al., Role of the autonomic nervous system in atrial fibrillation: pathophysiology and therapy. Circ Res, 2014. 114 (9): p. 1500-15. Brack, K.E., J. Winter, and G.A. Ng, Mechanisms underlying the autonomic modulation of ventricular fibrillation initiation--tentative prophylactic properties of vagus nerve stimulation on malignant arrhythmias in heart failure. Heart Fail Rev, 2013. 18 (4): p. 389-408. Kobayashi, M., et al., Cardiac autonomic nerve stimulation in the treatment of heart failure. Ann Thorac Surg, 2013. 96 (1): p. 339-45. Pauza, D.H., V. Skripka, and N. Pauziene, Morphology of the intrinsic cardiac nervous system in the dog: a whole-mount study employing histochemical staining with acetylcholinesterase. Cells Tissues Organs, 2002. 172 (4): p. 297-320. Armour, J.A., et al., Gross and microscopic anatomy of the human intrinsic cardiac nervous system. Anat Rec, 1997. 247 (2): p. 289-98. Zhou, Q., et al., Effect of the stellate ganglion on atrial fibrillation and atrial electrophysiological properties and its left-right asymmetry in a canine model. Exp Clin Cardiol, 2013. 18 (1): p. 38-42. Jung, B.C., et al., Circadian variations of stellate ganglion nerve activity in ambulatory dogs. Heart Rhythm, 2006. 3 (1): p. 78-85. Scherlag, B.J., et al., The Autonomic Nervous System and Atrial Fibrillation:The Roles of Pulmonary Vein Isolation and Ganglionated Plexi Ablation. J Atr Fibrillation, 2009. 2 (2): p. 177. Das, U.N., Vagus nerve stimulation as a strategy to prevent and manage metabolic syndrome. Med Hypotheses, 2011. 76 (3): p. 429-33. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-2765190\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":190806265,\"identity\":\"d1e46cb7-aa91-4e6f-b9e2-11da807b3e78\",\"order_by\":0,\"name\":\"Zhi Yang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Department of Cardiovascular Diseases, Branch of The First Affiliated Hospital of Xinjiang Medical University, Changji\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Zhi\",\"middleName\":\"\",\"lastName\":\"Yang\",\"suffix\":\"\"},{\"id\":190806267,\"identity\":\"202c4b6b-e269-42c5-8b1e-915f05cb2373\",\"order_by\":1,\"name\":\"Jianing Fan\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China National Clinical Research Center for Interventional Medicine\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Jianing\",\"middleName\":\"\",\"lastName\":\"Fan\",\"suffix\":\"\"},{\"id\":190806270,\"identity\":\"99d95dd1-dcfb-4530-8841-41bcfb7d3850\",\"order_by\":2,\"name\":\"Wenjing Xue\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Department of Cardiovascular Diseases, Jingshan Hospital Fudan University, Shanghai\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Wenjing\",\"middleName\":\"\",\"lastName\":\"Xue\",\"suffix\":\"\"},{\"id\":190806272,\"identity\":\"06afd459-9a20-4b5e-8463-bba9ad56d8b7\",\"order_by\":3,\"name\":\"Fuhua Lei\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Department of Cardiovascular Diseases, Jingshan Hospital Fudan University, Shanghai\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Fuhua\",\"middleName\":\"\",\"lastName\":\"Lei\",\"suffix\":\"\"},{\"id\":190806274,\"identity\":\"acf05e22-734d-4dd0-a4f7-3ab8275a0efb\",\"order_by\":4,\"name\":\"Feng Zhang\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYDAC5gMMDBIGNnL87A0MB4jTwpYA1FKRZizZc4AULQxnDiduuJFApLvk23jMJCzbDic23Hz+8HBBDYM8vxgByxjb2NIkJNvSjRtn5xgcnnGMwXDmbALWMcs3H7sh2WYt2yydw3CYh40hweA2AS1sbIxtQC3MjG2Sxx8c5vlHhBYeNuZjNyTOOCv2SDAYHOZtI0KLBBtb+g9QIEvwAP3C2ydB2C/AEDM2BkWl/fHjjz/zfLOR55cmoAUEmCWQbCWsHAQYPxCnbhSMglEwCkYqAABVXUAUS+k3zQAAAABJRU5ErkJggg==\",\"orcid\":\"\",\"institution\":\"Department of Cardiovascular Diseases, Jingshan Hospital Fudan University, Shanghai\",\"correspondingAuthor\":true,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Feng\",\"middleName\":\"\",\"lastName\":\"Zhang\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2023-04-01 13:44:41\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-2765190/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-2765190/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":35736539,\"identity\":\"84140d3f-a553-464e-b0c0-2fbde145f2c3\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:51:44\",\"extension\":\"jpg\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":519386,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eEffects of different frequency (1000 bpm and 500 bpm) on heart rate and representative electrocardiography. 1-3: body surface ECG in 500 bpm atrial pacing group; 4-6: : body surface ECG in 1000 bpm atrial pacing group.LAA: left atrial appendage, LSPV: left superior pulmonary vein.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"1.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/6050aecf800e6917827a818d.jpg\"},{\"id\":35736538,\"identity\":\"942576c1-a4f5-4920-9e2a-2a39a36a9308\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:51:44\",\"extension\":\"jpg\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":345764,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eEffects of different frequency (1000 bpm and 500 bpm) atrial pacing on atrial fibrillation (AF) sustained time, AF inducibility rate, effective refractory period (ERP) and dispersion of ERP (dERP). Decreased ERP, increased AF sustained time, AF inducibility rate and dERP were found in dogs from 1000 bpm group compared to 500 bpm group. St-Time: stimulation time, *p\\u0026lt;0.05 for between groups comparison.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"2.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/e75ec7d91af367c04e080315.jpg\"},{\"id\":35735424,\"identity\":\"4ec30d90-dce9-4cff-8e77-4b9fa5db9186\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:43:44\",\"extension\":\"jpg\",\"order_by\":3,\"title\":\"Figure 3\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":453737,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eNeural remodeling after 12 hours RAP. Representative figures of anti-ChAT staining in the 500 bpm and 1000 bpm group. Significantly increased sympathetic innervation density indicated by ChAT staining was found in 1000 bpm group compared to 500 bpm group.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"3.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/a4a8ab69052fcee8232cdce8.jpg\"},{\"id\":35735420,\"identity\":\"e5298b2c-0ff9-4d4d-bef1-1d5d529a820a\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:43:44\",\"extension\":\"jpg\",\"order_by\":4,\"title\":\"Figure 4\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":175007,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eEffects of different frequency (1000 bpm and 500 bpm) atrial pacing on discharge frequency and signal area of vagus nerve. Significantly difference was found on discharge frequency at 2, 4 and 6 hrs time points between 1000 bpm group compared to 500 bpm group. Increased signaling area score was found in dogs from 1000 bpm group compared to 500 bpm group. St-Time: stimulation time, *p\\u0026lt;0.05 for between groups comparison.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"4.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/3b016ec30ce5647913bdb433.jpg\"},{\"id\":35735423,\"identity\":\"614276d0-05c7-4e6b-9acc-c6988644093c\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:43:44\",\"extension\":\"jpg\",\"order_by\":5,\"title\":\"Figure 5\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":468730,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eEffects of different frequency (1000 bpm and 500 bpm) atrial pacing on vagus nerve activity feature curve.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"5.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/2c186dd4b960143299097a54.jpg\"},{\"id\":35735422,\"identity\":\"d7b75bbc-00ee-401c-8a68-6bb7c908cdda\",\"added_by\":\"auto\",\"created_at\":\"2023-04-13 22:43:44\",\"extension\":\"jpg\",\"order_by\":6,\"title\":\"Figure 6\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":145699,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eEffects of different frequency (1000 bpm and 500 bpm) atrial pacing on serum acetylcholine (Ach). Significantly increased serum Ach level was found at 2, 4 and 8 hrs time points in 1000 bpm group compared to 500 bpm group. St-Time: stimulation time, *p\\u0026lt;0.05 for between groups comparison.\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"6.jpg\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/93a8c37ebcf66f58e3b5aeb5.jpg\"},{\"id\":40520066,\"identity\":\"83f9284e-feef-4495-9ad6-13d5f86940e5\",\"added_by\":\"auto\",\"created_at\":\"2023-07-25 08:37:36\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":930089,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-2765190/v1/a7a89460-f192-4db1-964f-caf826c95a57.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"Effects of different intensity of atrial pacing on atrial electrophysiology and nerve remodeling\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003eAtrial fibrillation (AF) is a highly prevalent disease associated with pronounced morbidity and mortality [\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]. Despite the availability of numerous therapeutic agents, the available treatments have significant limitations[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e] and AF continues to be a clinical challenge.\\u003c/p\\u003e \\u003cp\\u003eAccumulating evidence has demonstrated that cardiac autonomic nerve remodeling (ANR), characterized by nerve regeneration, as well as by uneven distribution of the sympathetic and vagus nerves, is involved in the pathogenesis of both acute and chronic AF [\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e], and emerging evidence on autonomic modulation underscores its use as a novel treatment modality for AF[\\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e]. Moreover, rapid atrial pacing (RAP) could decrease the atrial effective refractory period, slow atrial conduction, and increase electrophysiologic heterogeneity [\\u003cspan additionalcitationids=\\\"CR9\\\" citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e\\u0026ndash;\\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e], thereby resulting in AF. However, no study compared the extract electrophysiological data and nerve eletrical signaling data in AF in the setting of different intensity of RAP.\\u003c/p\\u003e \\u003cp\\u003eIn present study, we employed a pair of unipolar electrodes to insert into the vagal trunk and recorded the nerve electrical signaling to elucidate the relationship between atrial pacing induced AF and features of nerve electrical signaling. Moreover, we also detected the electrophysiology data and serum acetylcholine level to evaluate the effects of vagus nerve. The data obtained here will provide nerve electrical basic information about the AF and autonomic nerve system.\\u003c/p\\u003e\"},{\"header\":\"Materials And Methods\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eEthical approval\\u0026nbsp;\\u003c/strong\\u003e\\u003cstrong\\u003eof the study protocol\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study protocol was approved by the Institutional Animal Care and Use Committee of the First Affiliated Hospital of Xinjiang Medical University, Uyghur city, Xinjiang Uyghur Autonomous Region, China. The study was conducted following international guidelines for animal experimentation.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAnimal and grouping\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eTwenty-four male adult beagle dogs weighing 10\\u0026ndash;15 kg provided by animal science center of Xinjiang Medical University were used in this study. Animals were randomly divided into control group (no stimulation, n\\u0026thinsp;=\\u0026thinsp;8), 500 bpm rapid atrial pacing (RAP) stimulation group (500 bpm group, n\\u0026thinsp;=\\u0026thinsp;8) and 1000 bpm rapid atrial pacing stimulation group (1000 bpm, n\\u0026thinsp;=\\u0026thinsp;8).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAnimal preparation\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAll the animals were fasting for food for 12 h and for drinking for 6 h. General anesthesia was induced with Ketamine 20 mg/kg and maintained with 3% sodium pentobarbital. Standard electrocardiography and pulse oximeter oxygen saturation were continuously monitored. Right femoral arteries and veins were cannulated and used for catheter insertion and blood pressure recording. The standard electrocardiographic lead II and blood pressure were continuously monitored using a pressure transducer. The right external jugular vein was cannulated and used for catheter insertion into the right atrium (RA) to record right atrial potentials and to perform RAP.A left-sided thoracotomy was performed at the fourth intercostal space. Multielectrode catheters were sutured to the left atrial appendage (LAA), left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV)[\\u003cspan class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e].\\u003c/p\\u003e\\n\\u003cdiv id=\\\"Sec5\\\" class=\\\"Section2\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eNerve signaling recording and analysis\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe right cervical vagal trunk was exposed by dissection, and a pair of unipolar electrodes (Streamline temporary myocardial pacing lead, Me-dtronic, Fridley, MN, USA) was inserted into the vagal trunk for RAP stimulation group. After signaling noise ratio(SNR)\\u0026thinsp;\\u0026gt;\\u0026thinsp;2.5 and stable, electrogram was recorded using LabChart 7 (AD Instruments, Colorado Springs, CO, USA) with filter setting of 50 to 200 Hz. Discharge frequency, amplitude and peak area score were recorded every 2 h after RAP stimulation, and analysis was performed using any 300 s nerve signaling figures during each time point.\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eRAP and electrophysiology\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eUnilateral electrical stimulation of the RAP at 500 beats/min (bpm) and 1000 bpm for 16 h were used to establish a canine model of AF. Before pacing and stimulation, the baseline electrophysiological data of AF inducibility, AF duration, effective refractory period (ERP) and dispersion of ERP (dERP) were measured. AF was defined as an irregular atrial rate\\u0026thinsp;\\u0026gt;\\u0026thinsp;450\\u0026ndash;600 beats/min and a duration\\u0026thinsp;\\u0026gt;\\u0026thinsp;5 s associated with irregular atrioventricular conduction [\\u003cspan class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]. AF inducibility rate was defined as successful AF times/total induction times. After pacing every 2 h, RAP stimulation was temporarily discontinued to obtain the electrophysiological data.\\u003c/p\\u003e\\n\\u003cp\\u003eContinuous RAP (500 or 1000 bpm, 0.5 ms, twice-threshold current) was administered to different groups of dogs at the RA for 16 h. Programmed stimulation at atrial sites or pulmonary vein sleeves was performed using a programmable cardiac stimulator (Lead-2000 EP Control, Sichuan Jinjiang, China). ERP was defined as the longest S1\\u0026ndash;S2 interval that failed to produce a response. ERP was measured at an atrial pacing cycle length of 300 ms, and the S1\\u0026ndash;S2 intervals were decreased from 200 ms by increments of 5 ms until no response was observed (S1:S2\\u0026thinsp;=\\u0026thinsp;8:1, twice-threshold current, 0.5 ms in duration). dERP was defined as the coefficient of variation (SD/mean) of the ERP at all four sites (LSPV, LIPV, LAA and RA).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eImmunohistochemical analysis\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAfter the electrophysiological study, ventricular fibrillation was induced by 9 V DC current to sacrifice the animals. Tissues were obtained from both atrial free walls. Immunohistochemical staining was performed for tyrosine hydroxylase (anti-TH antibody, Accurate Chemical \\u0026amp; Scientific Corporation, Westbury, NY, USA) and Choline Acetyltransferase (anti-CHAT antibody, Chemicon International Inc., Billerica, MA, USA) using the protocols described elsewhere [\\u003cspan class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]. Five high power fields from each slide, were randomly chosen and nerve density (anti-TH) or nerve sprouting (anti-CHAT) was automatically determined by the computerized detection of the stained brown color (Image-Pro 4.0).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eSerum acetylcholine (Ach) determination\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eVenous blood was collected into anticoagulant tubes before and every 2 h after pacing and stimulation. Serum were isolated by 3000 rpm centrifugation for 15 min and stored in -80\\u0026deg;C before further experimentation. Serum Ach level were determined by an ELISA kit according to manufacturer\\u0026rsquo;s instructions.\\u003c/p\\u003e\\n\\u003cdiv id=\\\"Sec9\\\" class=\\\"Section2\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eStatistical analysis\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAll the statistical analyses were performed using SPSS software version 19.0 (SPSS Inc., Chicago, IL, USA). Measurement data are expressed as mean\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;SD. Qualitative data are expressed as ratios. Values between the two groups were compared using paired \\u003cem\\u003et\\u003c/em\\u003e tests, and comparisons among multiple groups were made using ANOVA. ANOVA for repeated measures was used to compare the changes at different times during pacing and stimulation. The \\u0026chi;\\u003csup\\u003e2\\u003c/sup\\u003e test was used to compare qualitative data; P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05 was considered to be statistically significant.\\u003c/p\\u003e\\n\\u003c/div\\u003e\"},{\"header\":\"Results\",\"content\":\"\\u003cdiv id=\\\"Sec11\\\" class=\\\"Section2\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEffects of burst atrial pacing on the blood pressure and heart rates\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAtrial electrical stimulation could result 10\\u0026ndash;20% increasing of blood pressure and 10\\u0026ndash;20% increasing of heart rates compared to the baseline condition, which is persisting until the end of experiment (Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEffects of different frequency atrial pacing on AF sustained time, AF inducibility rate, ERP and dERP\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eIn order to evaluate the effects of different frequency atrial pacing on atrial electrophysiology, we firstly measured AF sustained time, AF inducibility rate, ERP and dERP under different frequency of electrical stimulation. As shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e, no significant difference was found at pre-stimulation on AF sustained time, AF inducibility rate, ERP and dERP between 1000 bpm and 500 bpm groups. Decreased ERP was found in 1000 bmp group compared to 500 bpm group and statistically significances were found at 2, 4, 6 and 8 hrs time points (all p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05). Significant increased AF sustained time were found at all time points in dogs from 1000 bpm group compared to 500 bpm group (all p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05). Furthermore, increased AF inducibility rates were found in 1000 bmp group compared to 500 bpm group and significantly increased percentages of 20.0%, 17.2%, 25.7%, 14.3%, 11.4% and 11.4% were respectively found at 2, 4, 6, 8, 10 and 12 h time points (all p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05). In addition, significantly increased dERPs were found at 2 and 4 h time points in 1000 bmp group compared to 500 bpm group (all p\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05).\\u0026nbsp;\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEffects of different frequency atrial pacing on nerual remodeling\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAfter 12 hours RAP, the nerve density of the atrium represented as the area positive for ChAT staining was significantly increased in 1000 bpm group compared to that in 500 bpm group (Fig.3).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEffects of different frequency atrial pacing on discharge frequency and signal area of vagus nerve\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThen we determined the effects of different frequency atrial pacing on discharge frequency and signal area of vagus nerve, the results were shown in Fig.\\u0026nbsp;4. The discharge frequency in 500 bpm group and 1000 bpm group at 0, 2, 4, 6, 8, 10, 12, 14 and 16 h were respectively 59, 81, 92, 129, 115, 106, 110, 100, 90 times and 58, 81, 133, 109, 106, 109, 95, 90, 92 times, and significant differences were found at 2, 4 and 6 h time points (all P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05). Moreover, signaling area in 500 bpm group and 1000 bpm group at 0, 2, 4, 6, 8, 10, 12, 14 and 16 h were respectively 4.35\\u0026micro;v.s, 69.61\\u0026micro;v.s, 53.35\\u0026micro;v.s, 35.18\\u0026micro;v.s, 18.96\\u0026micro;v.s, 16.90\\u0026micro;v.s, 11.30\\u0026micro;v.s, 14.13\\u0026micro;v.s, 16.81\\u0026micro;v.s and 6.70\\u0026micro;v.s, 77.66\\u0026micro;v.s, 94.65\\u0026micro;v.s, 10.43\\u0026micro;v.s, 17.07\\u0026micro;v.s, 12.56\\u0026micro;v.s, 33.87\\u0026micro;v.s, 28.30\\u0026micro;v.s, 12.30\\u0026micro;v.s, and significant differences were found at 2, 4, 6 and 8 h time points (all P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05). In addition, we also recorded the typical nerve activity feature curves under different atrial pacing stimulation, which were shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e5\\u003c/span\\u003e.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEffects of different frequency atrial pacing on serum Ach\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eFurthermore, we also determined the effects of different frequency atrial pacing on serum Ach and the results were shown in Fig.\\u0026nbsp;\\u003cspan class=\\\"InternalRef\\\"\\u003e6\\u003c/span\\u003e and Table.1. Significant differences were found at 2, 4 and 8 h time points in 1000 bpm group compared to 500 bpm group (all P\\u0026thinsp;\\u0026lt;\\u0026thinsp;0.05).\\u003c/p\\u003e\\n\\u003cdiv class=\\\"gridtable\\\"\\u003e\\n\\u003ctable id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e\\u003ccaption\\u003e\\n\\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e\\n\\u003cdiv class=\\\"CaptionContent\\\"\\u003e\\n\\u003cp\\u003eSerum acetylcholine at different time points between 500 bpm and 1000 bpm groups\\u003c/p\\u003e\\n\\u003c/div\\u003e\\n\\u003c/caption\\u003e\\n\\u003cthead\\u003e\\n\\u003ctr\\u003e\\n\\u003cth rowspan=\\\"2\\\" align=\\\"left\\\"\\u003e\\n\\u003cp\\u003eTime post stimulation\\u003c/p\\u003e\\n\\u003c/th\\u003e\\n\\u003cth colspan=\\\"2\\\" align=\\\"left\\\"\\u003e\\n\\u003cp\\u003eGroups\\u003c/p\\u003e\\n\\u003c/th\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003cth align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e500 bpm group\\u003c/p\\u003e\\n\\u003c/th\\u003e\\n\\u003cth align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e1000 bpm group\\u003c/p\\u003e\\n\\u003c/th\\u003e\\n\\u003c/tr\\u003e\\n\\u003c/thead\\u003e\\n\\u003ctbody\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e0 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e57.921\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;7.945\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e57.425\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.225\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e2 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" 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align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e10 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e58.743\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;5.225\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e60.405\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.703\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e12 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e57.383\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;9.676\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e62.473\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;3.671\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e14 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e56.783\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;8.831\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e63.531\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.832\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd align=\\\"left\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e16 h\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e54.431\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;6.921\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd align=\\\"char\\\" char=\\\"\\u0026plusmn;\\\"\\u003e\\n\\u003cp\\u003e57.984\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;4.921\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003c/tbody\\u003e\\n\\u003c/table\\u003e\\n\\u003c/div\\u003e\"},{\"header\":\"Discussion\",\"content\":\"\\u003cp\\u003eRAP stimulation could result in tension change of autonomic nerve system and increased atrial pacing, atrial nerve and electrical remodeling, and autonomic imbalance contributes to the initiation and maintenance of AF [\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e]. In present study, we found that significantly increased AF inducibility rate and sustained time in 1000 bpm group compared to 500 bpm group, however, no difference was found on the heart rates between these 2 groups. According to the electrophysiology features of cardiomyocytes, stimulation at resting could induce cardiac electrical excitation, whereas high frequency stimulation during ERP could only activate autonomic nerve but not myocardial electrical activity[\\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e]. Therefore, synchronous recording of vagus nerve stimulation could be achieved during high frequency stimulation, which could be helpful for exploration of the relationship between vagus nerve and AF.\\u003c/p\\u003e \\u003cp\\u003eThe Intrinsic Cardiac Nervous System (ICNS) and the Extrinsic Cardiac Nervous System (ECNS) constitute jointly the human cardiac nervous system. The ICNS in turn consists of interconnected groups of ganglia with axons and ganglionated plexi (GP) concentrated within the epicardial fat pad, which plays a functionally complex regulatory role.[\\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e]. These GPs may serve to incorporate autonomic signals and regulate the complicated relationship between ICNS and ECNS. Many authors have obtained heart rate variability (HRV) by calculating changes in the RR interval of the ECG signal in order to assess cardiac autonomic activity in a non-invasive manner. These variations are computed in the time- and frequency-domain; in the last case they are expressed as sinusoidal power values (power spectrum). Usually a decrease in sympathetic tone an increase in vagal tone can cause high HRV [\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e]. Great controversy exists in the absolute and relative variations of the power spectrum components related to sympathetic and parasympathetic modulation provoked by aerobic training [\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e].\\u003c/p\\u003e \\u003cp\\u003eZhou et al[\\u003cspan citationid=\\\"CR19\\\" class=\\\"CitationRef\\\"\\u003e19\\u003c/span\\u003e] demonstrated that the combination of unilateral electrical stimulation of the stellate ganglion (SG) with RAP enables the construction of a successful canine model of acute AF mediated by excess sympathetic activity. SG stimulation promoted the induction of atrial fibrillation and exacerbated electrical remodeling in the atrium and pulmonary vein sites. Unilateral stellate ganglionectomy inhibits sympathetic activation and reduces the occurrence of atrial fibrillation. This effect was achieved by suppressing the induction of AF and electrical remodeling at the atrial and pulmonary vein sites produced by SG activation. Jung et al[\\u003cspan citationid=\\\"CR20\\\" class=\\\"CitationRef\\\"\\u003e20\\u003c/span\\u003e] used Data Sciences International (DSI) transmitters to make continuous 24-h signal recordings of neural activity of SG in normally ambulatory dogs for an average of 41.5\\u0026thinsp;\\u0026plusmn;\\u0026thinsp;16.6 days. The results showed a circadian variation of sympathetic outflow. Both basic and clinical evidence suggests that, with regard to effects of ICANS, stimulation of GP promotes the development and maintenance of AF, with a significant decrease in the recurrence of AF in the correlated structures after transcatheter or surgical ablation of GP [\\u003cspan citationid=\\\"CR21\\\" class=\\\"CitationRef\\\"\\u003e21\\u003c/span\\u003e]. However, all these evidences only suggested possible association between CANS and AF, but not provide the quantitative data of nerve electrical signaling. Here, the right cervical vagal trunk was exposed by dissection, and a pair of unipolar electrodes was inserted into the vagal trunk for RAP stimulation group. We found that increased discharge frequency and signal area of vagus nerve were also found in dogs from 1000 bpm group compared to 500 bpm group. These results suggested that different degree of atrial and cardiac nerve remodeling could be generated by different atrial pacing, and high CANS activity could be achieved by high frequency stimulation. These results also consistent with the results that high frequency stimulation during ERP could only activate autonomic nerve but not myocardial electrical activity.\\u003c/p\\u003e \\u003cp\\u003eAch, the main vagal neurotransmitter, could shorten ERP and action potential and prolong the effects of dERP, which is critical for initiation and maintenance of AF[\\u003cspan citationid=\\\"CR22\\\" class=\\\"CitationRef\\\"\\u003e22\\u003c/span\\u003e]. According to the results obtained here, no significant changes were found on Ach level between 1000 bpm group and 500 bpm group, and both groups showed increased and time dependent manner of Ach level, which is consistent with nerve electrical features. The results of Ach obtained here suggested that initiation and maintenance of AF was closely related with nerve activation in 1000 bpm group, whereas atrial remodeling played a key role in 500 bpm group.\\u003c/p\\u003e \\u003cp\\u003eIn conclusion, we demonstrated here the association between nerve electrical activity of autonomic nervous system and atrial remodeling in AF, which might be a better target for employment of vagus nerve for the therapeutic purpose of AF. Further exploration the relationship between autonomic nervous system and AF could be helpful to understand the role of vagus nerve electrical activity on the initiation, maintain and refractory of the AF, which might be of clinical significance for decreasing the prevention and treatment of AF.\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eEthical Approval Consent to Participate:\\u0026nbsp;\\u003c/strong\\u003eThis study was in accordance with the Declaration of Helsinki and ARRIVE guidelines. The study protocol was approved by the Institutional Animal Care and Use Committee of the First Affiliated Hospital of Xinjiang Medical University, Uyghur city, Xinjiang Uyghur Autonomous Region, China.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConflict of interest:\\u003c/strong\\u003e none declared.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConsent for Publication:\\u0026nbsp;\\u003c/strong\\u003eNot applicable.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAuthors\\u0026rsquo; Contributors:\\u003c/strong\\u003e Zhi Yang and Jianing Fan wrote the main manuscript text and Wenjing Xue ,Fuhua Lei, Feng Zhang prepared figures. All authors reviewed the manuscript.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFunding:\\u0026nbsp;\\u003c/strong\\u003eThis research was supported by Fudan University Youth Research Fund(Grant No: JYQN-JC-202010). The funder has designed this study and decided to publish this manuscript.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAcknowledgment:\\u0026nbsp;\\u003c/strong\\u003eWe thank\\u003cstrong\\u003e\\u0026nbsp;\\u003c/strong\\u003eInstitutional Animal Experiment Center of the First Affiliated Hospital of Xinjiang Medical University for providing laboratories to ensure successful conduct of experiments.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAvailability of data and materials\\u0026nbsp;:\\u003c/strong\\u003eThe data that support the findings of this study are available on request from the corresponding author, [Feng Zhang]，upon reasonable request.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCompeting Interests:\\u003c/strong\\u003e The authors have declared that no competing interests exist.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n\\u003cli\\u003eZhang, Y., et al., \\u003cem\\u003eMicroRNA profiling of atrial fibrillation in canines: miR-206 modulates intrinsic cardiac autonomic nerve remodeling by regulating SOD1.\\u003c/em\\u003e PLoS One, 2015. \\u003cstrong\\u003e10\\u003c/strong\\u003e(3): p. e0122674.\\u003c/li\\u003e\\n\\u003cli\\u003eGillinov, A.M., et al., \\u003cem\\u003eRate control versus rhythm control for atrial fibrillation after cardiac surgery.\\u003c/em\\u003e New England Journal of Medicine, 2016. \\u003cstrong\\u003e374\\u003c/strong\\u003e(20): p. 1911-1921.\\u003c/li\\u003e\\n\\u003cli\\u003eNattel, S. and D. Dobrev, \\u003cem\\u003eControversies about atrial fibrillation mechanisms: aiming for order in chaos and whether it matters.\\u003c/em\\u003e Circulation research, 2017. \\u003cstrong\\u003e120\\u003c/strong\\u003e(9): p. 1396-1398.\\u003c/li\\u003e\\n\\u003cli\\u003eChang, C.M., et al., \\u003cem\\u003eNerve sprouting and sympathetic hyperinnervation in a canine model of atrial fibrillation produced by prolonged right atrial pacing.\\u003c/em\\u003e Circulation, 2001. \\u003cstrong\\u003e103\\u003c/strong\\u003e(1): p. 22-5.\\u003c/li\\u003e\\n\\u003cli\\u003eYu, F.S., et al., \\u003cem\\u003e[Nerve remodeling in a canine model of atrial fibrillation induced by 48 hours right atrial pacing].\\u003c/em\\u003e Zhonghua Xin Xue Guan Bing Za Zhi, 2010. \\u003cstrong\\u003e38\\u003c/strong\\u003e(7): p. 644-7.\\u003c/li\\u003e\\n\\u003cli\\u003eOh, S., et al., \\u003cem\\u003eVagal denervation and atrial fibrillation inducibility: epicardial fat pad ablation does not have long-term effects.\\u003c/em\\u003e Heart Rhythm, 2006. \\u003cstrong\\u003e3\\u003c/strong\\u003e(6): p. 701-8.\\u003c/li\\u003e\\n\\u003cli\\u003eShen, M.J., et al., \\u003cem\\u003eContinuous low-level vagus nerve stimulation reduces stellate ganglion nerve activity and paroxysmal atrial tachyarrhythmias in ambulatory canines.\\u003c/em\\u003e Circulation, 2011. \\u003cstrong\\u003e123\\u003c/strong\\u003e(20): p. 2204-12.\\u003c/li\\u003e\\n\\u003cli\\u003eSaengklub, N., et al., \\u003cem\\u003eDronedarone attenuates the duration of atrial fibrillation in a dog model of sustained atrial fibrillation.\\u003c/em\\u003e Exp Anim, 2017. \\u003cstrong\\u003e66\\u003c/strong\\u003e(3): p. 251-258.\\u003c/li\\u003e\\n\\u003cli\\u003eKijtawornrat, A., B.M. Roche, and R.L. Hamlin, \\u003cem\\u003eA canine model of sustained atrial fibrillation induced by rapid atrial pacing and phenylephrine.\\u003c/em\\u003e Comp Med, 2008. \\u003cstrong\\u003e58\\u003c/strong\\u003e(5): p. 490-3.\\u003c/li\\u003e\\n\\u003cli\\u003eAshikaga, K., et al., \\u003cem\\u003eEffects of amiodarone on electrical and structural remodeling induced in a canine rapid pacing-induced persistent atrial fibrillation model.\\u003c/em\\u003e Eur J Pharmacol, 2006. \\u003cstrong\\u003e536\\u003c/strong\\u003e(1-2): p. 148-53.\\u003c/li\\u003e\\n\\u003cli\\u003eLiu, F., et al., \\u003cem\\u003eLow-Level Stimulation and Ethanol Ablation of the Vein of Marshall Prevent the Vagal-Mediated AF.\\u003c/em\\u003e Front Cardiovasc Med, 2021. \\u003cstrong\\u003e8\\u003c/strong\\u003e: p. 675485.\\u003c/li\\u003e\\n\\u003cli\\u003eLu, Z., et al., \\u003cem\\u003eAtrial fibrillation begets atrial fibrillation: autonomic mechanism for atrial electrical remodeling induced by short-term rapid atrial pacing.\\u003c/em\\u003e Circ Arrhythm Electrophysiol, 2008. \\u003cstrong\\u003e1\\u003c/strong\\u003e(3): p. 184-92.\\u003c/li\\u003e\\n\\u003cli\\u003eCao, J.M., et al., \\u003cem\\u003eRelationship between regional cardiac hyperinnervation and ventricular arrhythmia.\\u003c/em\\u003e Circulation, 2000. \\u003cstrong\\u003e101\\u003c/strong\\u003e(16): p. 1960-9.\\u003c/li\\u003e\\n\\u003cli\\u003eChen, P.S., et al., \\u003cem\\u003eRole of the autonomic nervous system in atrial fibrillation: pathophysiology and therapy.\\u003c/em\\u003e Circ Res, 2014. \\u003cstrong\\u003e114\\u003c/strong\\u003e(9): p. 1500-15.\\u003c/li\\u003e\\n\\u003cli\\u003eBrack, K.E., J. Winter, and G.A. Ng, \\u003cem\\u003eMechanisms underlying the autonomic modulation of ventricular fibrillation initiation--tentative prophylactic properties of vagus nerve stimulation on malignant arrhythmias in heart failure.\\u003c/em\\u003e Heart Fail Rev, 2013. \\u003cstrong\\u003e18\\u003c/strong\\u003e(4): p. 389-408.\\u003c/li\\u003e\\n\\u003cli\\u003eKobayashi, M., et al., \\u003cem\\u003eCardiac autonomic nerve stimulation in the treatment of heart failure.\\u003c/em\\u003e Ann Thorac Surg, 2013. \\u003cstrong\\u003e96\\u003c/strong\\u003e(1): p. 339-45.\\u003c/li\\u003e\\n\\u003cli\\u003ePauza, D.H., V. Skripka, and N. Pauziene, \\u003cem\\u003eMorphology of the intrinsic cardiac nervous system in the dog: a whole-mount study employing histochemical staining with acetylcholinesterase.\\u003c/em\\u003e Cells Tissues Organs, 2002. \\u003cstrong\\u003e172\\u003c/strong\\u003e(4): p. 297-320.\\u003c/li\\u003e\\n\\u003cli\\u003eArmour, J.A., et al., \\u003cem\\u003eGross and microscopic anatomy of the human intrinsic cardiac nervous system.\\u003c/em\\u003e Anat Rec, 1997. \\u003cstrong\\u003e247\\u003c/strong\\u003e(2): p. 289-98.\\u003c/li\\u003e\\n\\u003cli\\u003eZhou, Q., et al., \\u003cem\\u003eEffect of the stellate ganglion on atrial fibrillation and atrial electrophysiological properties and its left-right asymmetry in a canine model.\\u003c/em\\u003e Exp Clin Cardiol, 2013. \\u003cstrong\\u003e18\\u003c/strong\\u003e(1): p. 38-42.\\u003c/li\\u003e\\n\\u003cli\\u003eJung, B.C., et al., \\u003cem\\u003eCircadian variations of stellate ganglion nerve activity in ambulatory dogs.\\u003c/em\\u003e Heart Rhythm, 2006. \\u003cstrong\\u003e3\\u003c/strong\\u003e(1): p. 78-85.\\u003c/li\\u003e\\n\\u003cli\\u003eScherlag, B.J., et al., \\u003cem\\u003eThe Autonomic Nervous System and Atrial Fibrillation:The Roles of Pulmonary Vein Isolation and Ganglionated Plexi Ablation.\\u003c/em\\u003e J Atr Fibrillation, 2009. \\u003cstrong\\u003e2\\u003c/strong\\u003e(2): p. 177.\\u003c/li\\u003e\\n\\u003cli\\u003eDas, U.N., \\u003cem\\u003eVagus nerve stimulation as a strategy to prevent and manage metabolic syndrome.\\u003c/em\\u003e Med Hypotheses, 2011. \\u003cstrong\\u003e76\\u003c/strong\\u003e(3): p. 429-33.\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Atrial fibrillation, autonomic nervous system, vagus nerve, nerve electrical signaling, acetylcholine\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-2765190/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-2765190/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003e\\u003cstrong\\u003eBackground and Objective\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAtrial fibrillation (AF) could be induced by different intensity of atrial pacing, however the detail information during these processes have not been fully explored. The aim of this study was to evaluate the effects of different intensity of atrial pacing on atrial electrophysiology.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eMethods\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eTwenty-four dogs were randomly subjected to 16 hours atrial pacing at 500 beats/min (bpm) or 1000 bpm as follows: no stimulation (control, n = 8), 500 bpm stimulation (500 bpm, n = 8) and 1000 bpm stimulation (1000 bpm, n = 8). Programmed and burst atrial pacing were performed at baseline and at the end of every 2 hour to determine AF inducibility, sustained time of AF and atrial effective refractory period (ERP). Moreover, the electrical activities of vagus nerve including discharge frequency, signal area were also recorded. In addition, serum acetylcholine (Ach) was determined by ELISA to explore the relationship with AF and vagus nerve features.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eResults\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eIncreased AF inducibility, sustained time of AF and ERP were found in dogs from 1000 bpm group compared to 500 bpm group. Moreover, increased discharge frequency and signal area of vagus nerve were also found in dogs from 1000 bpm group compared to 500 bpm group. Correlation was found between the serum Ach and AF.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConclusions\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eOur results demonstrated that different intensity of atrial pacing exerted different effects on atrial electrophysiology and nerve remodeling, while high-frequency electrical stimulation are more prone to autonomic nervous activity induction.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Effects of different intensity of atrial pacing on atrial electrophysiology and nerve remodeling\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2023-04-13 22:43:39\",\"doi\":\"10.21203/rs.3.rs-2765190/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"99a68517-e6d1-4e19-9414-bc6de367b08d\",\"owner\":[],\"postedDate\":\"April 13th, 2023\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2023-07-25T08:29:26+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2023-04-13 22:43:39\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-2765190\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-2765190\",\"identity\":\"rs-2765190\",\"version\":[\"v1\"]},\"buildId\":\"rHA-KDH7Qsr4HCuvH75dn\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}