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Pachon-M JC, Pachon-M EI, Pachon CTC, Santillana-P TG, Lobo TJ, Pachon-M JC, Higuti C, Zerpa-A JC, Pachon MZC, Ortencio FA, Osorio TG, Peixoto LA. Long-term outcomes of cardioneuroablation with and without extra-cardiac vagal stimulation confirmation in severe cardioinhibitory neurocardiogenic syncope. J Cardiovasc Electrophysiol 2024; 35:641-650. [PMID: 38240356 DOI: 10.1111/jce.16188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/27/2023] [Accepted: 01/06/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND Cardioneuroablation (CNA) is a novel therapeutic approach for functional bradyarrhythmias, specifically neurocardiogenic syncope or atrial fibrillation, achieved through endocardial radiofrequency catheter ablation of vagal innervation, obviating the need for pacemaker implantation. Originating in the nineties, the first series of CNA procedures was published in 2005. Extra-cardiac vagal stimulation (ECVS) is employed as a direct method for stepwise denervation control during CNA. OBJECTIVE This study aimed to compare the long-term follow-up outcomes of patients with severe cardioinhibitory syncope undergoing CNA with and without denervation confirmation via ECVS. METHOD A cohort of 48 patients, predominantly female (56.3%), suffering from recurrent syncope (5.1 ± 2.5 episodes annually) that remained unresponsive to clinical and pharmacological interventions, underwent CNA, divided into two groups: ECVS and NoECVS, consisting of 34 and 14 cases, respectively. ECVS procedures were conducted with and without atrial pacing. RESULTS Demographic characteristics, left atrial size, and ejection fraction displayed no statistically significant differences between the groups. Follow-up duration was comparable, with 29.1 ± 15 months for the ECVS group and 31.9 ± 20 months for the NoECVS group (p = .24). Notably, syncope recurrence was significantly lower in the ECVS group (two cases vs. four cases, Log Rank p = .04). Moreover, the Hazard ratio revealed a fivefold higher risk of syncope recurrence in the NoECVS group. CONCLUSION This study demonstrates that concluding CNA with denervation confirmation via ECVS yields a higher success rate and a substantially reduced risk of syncope recurrence compared to procedures without ECVS confirmation.
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Affiliation(s)
- Jose Carlos Pachon-M
- Sao Paulo University, Sao Paulo, Brazil
- Sao Paulo Heart Hospital, Sao Paulo, Brazil
| | - Enrique I Pachon-M
- Sao Paulo University, Sao Paulo, Brazil
- Sao Paulo Heart Hospital, Sao Paulo, Brazil
| | | | | | | | - Juan C Pachon-M
- Sao Paulo University, Sao Paulo, Brazil
- Sao Paulo Heart Hospital, Sao Paulo, Brazil
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Yarkoni M, Rehman WU, Bajwa A, Yarkoni A, Rehman AU. Ganglionated Plexus Ablation Procedures to Treat Vasovagal Syncope. Int J Mol Sci 2023; 24:13264. [PMID: 37686062 PMCID: PMC10487499 DOI: 10.3390/ijms241713264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
Vasovagal syncope (VVS) refers to a heterogeneous group of conditions whereby the cardiovascular reflexes normally controlling the circulation are interrupted irregularly in response to a trigger, resulting in vasodilation, bradycardia, or both. VVS affects one-third of the population at least once in their lifetime or by the age of 60, reduces the quality of life, and may cause disability affecting certain routines. It poses a considerable economic burden on society, and, despite its prevalence, there is currently no proven pharmacological treatment for preventing VVS. The novel procedure of ganglionated plexus (GP) ablation has emerged rapidly in the past two decades, and has been proven successful in treating syncope. Several parameters influence the success rate of GP ablation, including specific ablation sites, localization and surgical techniques, method of access, and the integration of other interventions. This review aims to provide an overview of the existing literature on the physiological aspects and clinical effectiveness of GP ablation in the treatment of VVS. Specifically, we explore the association between GPs and VVS and examine the impact of GP ablation procedures as reported in human clinical trials. Our objective is to shed light on the therapeutic significance of GP ablation in eliminating VVS and restoring normal sinus rhythm, particularly among young adults affected by this condition.
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Affiliation(s)
- Merav Yarkoni
- Heart and Vascular Institute, United Health Services, Johnson City, NY 13790, USA; (W.u.R.); (A.B.); (A.Y.); (A.u.R.)
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3
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Pachon-M EI, Pachon-Mateos JC, Higuti C, Santillana-P TG, Lobo T, Pachon C, Pachon-Mateos J, Zerpa J, Ortencio F, Amarante RC, Silva RF, Osório TG. Relation of Fractionated Atrial Potentials With the Vagal Innervation Evaluated by Extracardiac Vagal Stimulation During Cardioneuroablation. Circ Arrhythm Electrophysiol 2020; 13:e007900. [PMID: 32188285 DOI: 10.1161/circep.119.007900] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Vagal hyperactivity is directly related to several clinical conditions as reflex/functional bradyarrhythmias and vagal atrial fibrillation (AF). Cardioneuroablation provides therapeutic vagal denervation through endocardial radiofrequency ablation for these cases. The main challenges are neuromyocardium interface identification and the denervation control and validation. The finding that the AF-Nest (AFN) ablation eliminates the atropine response and decreases RR variability suggests that they are related to the vagal innervation. METHOD Prospective, controlled, longitudinal, nonrandomized study enrolling 62 patients in 2 groups: AFN group (AFN group 32 patients) with functional or reflex bradyarrhythmias or vagal AF treated with AFN ablation and a control group (30 patients) with anomalous bundles, ventricular premature beats, atrial flutter, atrioventricular nodal reentry, and atrial tachycardia, treated with conventional ablation (non-AFN ablation). In AFN group, ablation delivered at AFN detected by fragmentation/fractionation of the endocardial electrograms and by 3-dimensional anatomic location of the ganglionated plexus. Vagal response was evaluated before, during, and postablation by 5 s noncontact vagal stimulation at the jugular foramen, through the internal jugular veins (extracardiac vagal stimulation [ECVS]), analyzing 15 s mean heart rate, longest RR, pauses, and atrioventricular block. All patients had current guidelines arrhythmia ablation indication. RESULTS Preablation ECVS induced sinus pauses, asystole, and transient atrioventricular block in both groups showing a strong vagal response (P=0.96). Postablation ECVS in the AFN group showed complete abolishment of the cardiac vagal response in all cases (pre/postablation ECVS=P<0.0001), demonstrating robust vagal denervation. However, in the control group, vagal response remained practically unchanged postablation (P=0.35), showing that non-AFN ablation promotes no significant denervation. CONCLUSIONS AFN ablation causes significant vagal denervation. Non-AFN ablation causes no significant vagal denervation. These results suggest that AFNs are intrinsically related to vagal innervation. ECVS was fundamental to stepwise vagal denervation validation during cardioneuroablation. Visual Overview A visual overview is available for this article.
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Affiliation(s)
- Enrique I Pachon-M
- Sao Paulo University, Brazil (E.I.P.-M., J.C.P.-M., J.P.-M., R.C.A.).,Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.).,Dante Pazzanese Cardiology Institute, Sao Paulo, Brazil (J.C.P.-M., C.H., J.P.-M., R.C.A., R.F.S.). Brussels Universiteit, Belgium (T.G.O)
| | - Jose Carlos Pachon-Mateos
- Sao Paulo University, Brazil (E.I.P.-M., J.C.P.-M., J.P.-M., R.C.A.).,Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Christian Higuti
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.).,Dante Pazzanese Cardiology Institute, Sao Paulo, Brazil (J.C.P.-M., C.H., J.P.-M., R.C.A., R.F.S.). Brussels Universiteit, Belgium (T.G.O)
| | - Tomas G Santillana-P
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Tasso Lobo
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Carlos Pachon
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Juan Pachon-Mateos
- Sao Paulo University, Brazil (E.I.P.-M., J.C.P.-M., J.P.-M., R.C.A.).,Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.).,Dante Pazzanese Cardiology Institute, Sao Paulo, Brazil (J.C.P.-M., C.H., J.P.-M., R.C.A., R.F.S.). Brussels Universiteit, Belgium (T.G.O)
| | - Juan Zerpa
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Felipe Ortencio
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.)
| | - Ricardo Carneiro Amarante
- Sao Paulo University, Brazil (E.I.P.-M., J.C.P.-M., J.P.-M., R.C.A.).,Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.).,Dante Pazzanese Cardiology Institute, Sao Paulo, Brazil (J.C.P.-M., C.H., J.P.-M., R.C.A., R.F.S.). Brussels Universiteit, Belgium (T.G.O)
| | - Ricardo Ferreira Silva
- Heart Hospital, Sao Paulo, Brazil (E.I.P.-M., J.C.P.-M., C.H., T.G.S-P., T.L., C.P., J.P.-M., J.Z.,F.O., R.F.S, R.C.A.).,Dante Pazzanese Cardiology Institute, Sao Paulo, Brazil (J.C.P.-M., C.H., J.P.-M., R.C.A., R.F.S.). Brussels Universiteit, Belgium (T.G.O)
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Carlos Pachon Mateos J, I Pachón Mateos E, Higuti C, Guilhermo Santillana Peña T, Julio Lobo T, Thiene Cunha Pachón C, Carlos Pachón Mateos J, Carlos Zerpa Acosta J, Ortencio F, Amarante R. Cardioneuroablation: Catheter Vagal Denervation as a New Therapy for Cardioinhibitory Syncope. JOURNAL OF CARDIAC ARRHYTHMIAS 2020. [DOI: 10.24207/jca.v32n3.067_in] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The vasovagal syncope is the most frequent cause of transient loss of consciousness, especially in young people without significant heart disease. The malignant cardioinhibitory form is caused by abrupt and intense vagal reflex with or without defined triggers. Refractory cases to preventive measures and pharmacological handling has been treated with definitive pacemaker implantation. Besides showing questionable results, pacemaker implantation is highly rejected by young patients. In the late 1990s, we proposed specific vagal denervation by catheter ablation and spectral mapping, for paroxysmal AF, functional bradyarrhythmias and severe cases of malignant cardioinhibitory syncope giving rise to cardioneuroablation. Recently, many authors worldwide have been reproducing the cardioneuroablation results where elimination or significant reduction of the vagal response were observed, which abolished symptoms in more than 75% of patients followed up to 14 years, without complications. Therefore, cardioneuroablation has shown to be a real therapeutic option in malignant syncope cardioinhibitory and in any exclusive vagal mediated bradyarrhythmia without the need for pacemaker implantation.
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Affiliation(s)
| | | | | | | | - Tasso Julio Lobo
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
| | | | | | - Juán Carlos Zerpa Acosta
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
| | - Felipe Ortencio
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
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Carlos Pachon Mateos J, I Pachón Mateos E, Higuti C, Guilhermo Santillana Peña T, Julio Lobo T, Thiene Cunha Pachón C, Carlos Pachón Mateos J, Carlos Zerpa Acosta J, Ortencio F, Amarante R. Cardioneuroablação: A Denervação Vagal por Cateter Como Nova Terapia para Síncope Cardioinibitória. JOURNAL OF CARDIAC ARRHYTHMIAS 2020. [DOI: 10.24207/jca.v32n3.067_pt] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A síncope vasovagal é a causa mais frequente de perda transitória de consciência, especialmente em jovens sem doença cardíaca significativa. A forma cardioinibitória maligna é causada por reflexo vagal abrupto e intenso com ou sem gatilhos definidos. Casos refratários a medidas preventivas e manuseio farmacológico foram tratados com implante definitivo de marcapasso. Além de apresentar resultados questionáveis, o implante de marcapasso é altamente rejeitado por pacientes jovens. No final dos anos 1990, propusemos uma denervação vagal específica por ablação do cateter e mapeamento espectral para FA paroxística, bradiarritmias funcionais e casos graves de síncope cardioinibitória maligna dando origem à cardioneuroablação. Recentemente, muitos autores em todo o mundo vêm reproduzindo os resultados da cardioneuroablação, onde se observou eliminação ou redução significativa da resposta vagal, o que aboliu sintomas em mais de 75% dos pacientes acompanhados por até 14 anos, sem complicações. Portanto a cardioneuroablação tem se mostrado uma verdadeira opção terapêutica na síncope cardioinibitória maligna e em qualquer bradiarritmia vagal exclusiva mediada sem a necessidade de implante de marcapasso.
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Affiliation(s)
| | | | | | | | - Tasso Julio Lobo
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
| | | | | | - Juán Carlos Zerpa Acosta
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
| | - Felipe Ortencio
- Hospital do Coração - Serviço de Eletrofisiologia, Marcapasso e Arritmias - São Paulo (SP) – Brazil
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6
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Affiliation(s)
- Jose Carlos Pachon-M
- São Paulo University, São Paulo Heart Hospital, and São Paulo Dante Pazzanese Cardiology Institute, São Paulo, Brazil.
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Giannopoulos G, Kossyvakis C, Angelidis C, Panagopoulou V, Tsiachris D, Vrachatis DA, Doudoumis K, Letsas K, Pagoni S, Stefanadis C, Vassilikos VP, Lekakis J, Deftereos S. Coincidental ganglionated plexus modification during radiofrequency pulmonary vein isolation and post-ablation arrhythmia recurrence. Europace 2018; 19:1967-1972. [PMID: 29194518 DOI: 10.1093/europace/euw309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 09/03/2016] [Indexed: 11/14/2022] Open
Abstract
Aims Vagal responses (VR) during left atrial ablation for atrial fibrillation (AF) treatment have been reported to be associated with less recurrences, presumably because they are a sign of ganglionated plexi modification. Our objective was to evaluate whether coincidentally elicited VR during left atrial ablation are associated with lower AF recurrence rates. Methods and results This is a post hoc analysis of a prospective study of 291 patients with paroxysmal AF undergoing radiofrequency pulmonary vein isolation (PVI). Vagal responses were defined as episodes of heart rate <40 bpm or asystole lasting >5 s elicited during energy application. Sixty-eight patients (23.4%) had a VR during ablation. In Kaplan-Meier analysis, mean recurrence-free survival was 449 days (95% confidence interval 411-488) in patients with VR when compared with 435 days (95% confidence interval 415-455) in those without (P = 0.310). The 12-month recurrence rate estimates were 25 and 27%, respectively. In an unadjusted Cox model, VR was associated with an odds ratio for recurrence of 0.77 (95% confidence interval 0.46-1.28). Conclusion Coincidentally elicited VR during radiofrequency PVI in patients with paroxysmal AF do not appear to be related to lower risk of arrhythmia recurrence. This may mean that, even if a VR is truly a sign of coincidental ablation of a ganglionated plexus, this does not necessarily mean that a therapeutic modification has been effected, at least to a degree associated with clinical benefit.
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Affiliation(s)
- Georgios Giannopoulos
- 2nd Department of Cardiology, National and Kapodistrean University of Athens Medical School, Attikon University Hospital, Athens, Greece.,Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, CT, USA.,Athens Heart Center, Athens Medical Center, Athens, Greece
| | - Charalampos Kossyvakis
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, CT, USA.,Cardiology Department, Athens General Hospital 'G. Gennimatas', Athens, Greece
| | - Christos Angelidis
- 2nd Department of Cardiology, National and Kapodistrean University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Vasiliki Panagopoulou
- 2nd Department of Cardiology, National and Kapodistrean University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | | | | | | | | | - Stamatina Pagoni
- Cardiology Department, Athens General Hospital 'G. Gennimatas', Athens, Greece
| | | | - Vassilios P Vassilikos
- 3rd Department of Cardiology, Ippokrateio General Hospital, Aristotle University of Thessaloniki, Greece
| | - John Lekakis
- 2nd Department of Cardiology, National and Kapodistrean University of Athens Medical School, Attikon University Hospital, Athens, Greece
| | - Spyridon Deftereos
- 2nd Department of Cardiology, National and Kapodistrean University of Athens Medical School, Attikon University Hospital, Athens, Greece.,Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, CT, USA
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Pachón-M JC, Pachón-M EI, Santillana P TG, Lobo TJ, Pachón CTC, Pachón-M JC, Albornoz V RN, Zerpa A JC, Ortencio F, Arruda M. Ablation of "Background Tachycardia" in Long Standing Atrial Fibrillation: Improving the Outcomes by Unmasking a Residual Atrial Fibrillation Perpetuator. J Atr Fibrillation 2017; 10:1583. [PMID: 29250230 DOI: 10.4022/jafib.1583] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/19/2017] [Accepted: 08/14/2017] [Indexed: 11/10/2022]
Abstract
Background Catheter ablation of long-standing persistent AF (LSAF) remains challenging. Since AF-Nest (AFN) description, we have observed that a stable, protected, fast source firing, namely "Background Tachycardia"(BT), could be hidden beneath the chaotic AF. Following pulmonary vein isolation (PVI)+AFN ablation one or more BT may arise or be induced in 30-40% of patients, which could be the culprit forAF maintenance and ablation recurrences. Methods and Results We studied 114 patients, from 322 sequential LSAF regular ablations, having spontaneous or induced residual BT after EGM-guided PVI+AFN ablation of LSAF; 55.6±11y/o, 97males (85.1%), EF=65.5±8%, LA=42.8±6.7mm. Macroreentrant tachycardias were excluded. Pre-ablationAF 12-leads ECG Digital processing(DP) and spectral analysis(SA) was performed searching for BT before AF ablation and its correlation with BT during ablation.After PVI, 38.1±9 AFN sites/patient and 135 sustained BTs (1-3, 1.2±0.5/patient) were ablated. BT cycle length(CL) was 246.3±37.3ms. In 79 patients presenting suitable DP for SA, the BT-CL was 241.6±34.3ms with intra procedure BT-CL correlation r=0.83/p<0.01. Following BT ablation, AF could not be induced. During FU of 13→60 months(22.8±12m), AF freedom for BT RF(+) vs. BT RF(-) groups were 77.9% vs. 56.4% (p=0.009), respectively. There was no significant complication. Conclusion BT ablation following PVI and AFN ablation improved long-term outcomes ofLSAF ablation. BT is likely due to sustained microreentry, protected during AF by entry block. BT can be suspected by spectral analysis of the pre-ablation ECG and is likely one important AF perpetuator by causing electrical resonance of the AFN. This ablation strategy warrants randomized, multicenter investigation.
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Affiliation(s)
- José Carlos Pachón-M
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Enrique I Pachón-M
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Tomas G Santillana P
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Tasso Julio Lobo
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Carlos Thiene C Pachón
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Juán Carlos Pachón-M
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Remy Nelson Albornoz V
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Juán Carlos Zerpa A
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Felipe Ortencio
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
| | - Mauricio Arruda
- Institutional review board statement: The study was reviewed and approved by theinstitutional review boards of Sao Paulo Cardiology Institute (IDPC) and Sao Paulo University (USP)
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Pachón-Mateos JC, Pachón-Mateos EI. Letter by Pachón-Mateos and Pachón-Mateos Regarding Article, "Targets and End Points in Cardiac Autonomic Denervation Procedures" and Editorial, "Selective Modulation of the Cardiac Autonomic Nervous System: A New Strategy for Treatment of Cardioinhibitory Syncope". Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005256. [PMID: 28705877 DOI: 10.1161/circep.117.005256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Feldman A, Moreira DAR, Gun C, Wang HTL, Hirata MH, de Freitas Germano J, Leite GGS, Farsky P. Analysis of Circulating miR-1, miR-23a, and miR-26a in Atrial Fibrillation Patients Undergoing Coronary Bypass Artery Grafting Surgery. Ann Hum Genet 2017; 81:99-105. [PMID: 28422282 DOI: 10.1111/ahg.12188] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 01/04/2023]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery. From a pathophysiological point of view, a myriad of factors such as trauma, atrial dilation, ischemia, mechanical myopericarditis, autonomic imbalance, loss of connexins, AF nest remodeling, inflammation, sutures, and dysfunction caused by postextracorporeal circulation can contribute to postoperative atrial fibrillation (POAF) resulting in a longer hospital stay and consequently higher cost. Recent studies showed that short fragments of RNA, called microRNA (miRNA), can contribute to the development of several cardiovascular diseases, including AF. The aim of this study was to evaluate the levels of circulating miRNAs (miR-1, -23a, and -26a) that can be involved in POAF. Patients submitted to coronary artery bypass graft surgery were grouped in POAF (24 patients) and without POAF (24 patients). Results showed older age, longer clamp-time, and more days in the intensive care unit as well as a longer total hospital stay in the POAF group. Preoperative levels of circulating miRNAs were similar. Analysis of miRNAs revealed significantly lower circulating levels of miRNA-23a (P = 0.02) and -26a (P = 0.01) in the POAF group during the postoperative period. Receiver operating characteristic (ROC) analysis showed the area under the ROC curve of miR-23a and miR-26a for predicting FA was 0.63 (95% confidence interval [CI]: 0.51-0.74; P = 0.02) and 0.66 (95% CI: 0.55-0.77; P = 0.01), respectively. Our data suggests that circulating miRNA-23a and -26a may be involved in the underlying biology of postoperative AF development.
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Affiliation(s)
- Andre Feldman
- Instituto Dante Pazzanese de Cardiologia Sao Paulo, São Paulo, BR
| | | | - Carlos Gun
- Instituto Dante Pazzanese de Cardiologia Sao Paulo, São Paulo, BR
| | - Hui-Tzu Lin Wang
- Instituto Dante Pazzanese de Cardiologia Sao Paulo, São Paulo, BR
| | | | | | | | - Pedro Farsky
- Instituto Dante Pazzanese de Cardiologia Sao Paulo, São Paulo, BR
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Wake E, Brack K. Characterization of the intrinsic cardiac nervous system. Auton Neurosci 2016; 199:3-16. [DOI: 10.1016/j.autneu.2016.08.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/29/2016] [Accepted: 08/03/2016] [Indexed: 11/29/2022]
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Lo LW, Chang HY, Scherlag BJ, Lin YJ, Chou YH, Lin WL, Chen SA, Po SS. Temporary Suppression of Cardiac Ganglionated Plexi Leads to Long-Term Suppression of Atrial Fibrillation: Evidence of Early Autonomic Intervention to Break the Vicious Cycle of "AF Begets AF". J Am Heart Assoc 2016; 5:JAHA.116.003309. [PMID: 27381759 PMCID: PMC5015371 DOI: 10.1161/jaha.116.003309] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Botulinum toxin (BTX), temporarily suppressing cholinergic transmission (<3 weeks), has been reported to suppress atrial fibrillation (AF) for ≥1 year. We aimed to investigate the mechanism underlying long-term suppression of AF caused by injecting BTX into major atrial ganglionated plexi (GPs). METHODS AND RESULTS Bilateral thoracotomies in anesthetized dogs allowed programmed stimulation at 4 pulmonary veins, biatrial appendages, and the superior vena cava to determine the effective refractory period (ERP) in the first operation. Group 1 (n=10) received BTX injection into all GPs; group 2 (n=7) received no injection. Groups 1 and 2 received rapid atrial pacing (800 bpm) 6 days a week. Group 3 (n=7) did not undergo thoracotomy or rapid atrial pacing to serve as controls for histological studies. A second operation and the same measurements were made 3 months later. During the first operation in group 1, ERPs of 4 pulmonary veins, but not biatrial appendages or superior vena cava, increased immediately after BTX injection. AF burdens increased significantly from the fifth week after the first operation in group 2 but not in group 1. In the second operation, ERPs remained unchanged compared with ERPs before BTX injection in group 1, whereas ERPs shortened significantly at all sites except the superior vena cava in group 2. There was no difference of autonomic nerve density between group 1 and group 3. The GP choline acetyltransferase (+) and atrial tyrosine hydroxylase (+) nerve densities were higher in group 2 than in group 1 and group 3. CONCLUSIONS Temporary suppression of major atrial GPs by BTX prevents autonomic remodeling and provides long-term suppression of AF, indicating the critical role of GPs in AF progression.
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Affiliation(s)
- Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Hung-Yu Chang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Benjamin J Scherlag
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Hui Chou
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wei-Lun Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei, Taiwan
| | - Sunny S Po
- Department of Medicine and Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK
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Zaman JAB, Harling L, Ashrafian H, Darzi A, Gooderham N, Athanasiou T, Peters NS. Post-operative atrial fibrillation is associated with a pre-existing structural and electrical substrate in human right atrial myocardium. Int J Cardiol 2016; 220:580-8. [PMID: 27390994 PMCID: PMC4994770 DOI: 10.1016/j.ijcard.2016.06.249] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 06/01/2016] [Accepted: 06/26/2016] [Indexed: 12/19/2022]
Abstract
Background Post-operative atrial fibrillation (POAF) is a major health economic burden. However, the precise mechanisms in POAF remain unclear. In other forms of AF, sites of high dominant frequency (DF) in sinus rhythm (SR) may harbour ‘AF nests’. We studied AF inducibility in relation to substrate changes using epicardial electrograms and cardiomyocyte calcium handling in the atria of AF naïve patients. Method Bipolar electrograms were recorded from the lateral right atrial (RA) wall in 34 patients undergoing coronary surgery using a high-density array in sinus rhythm (NSR). RA burst pacing at 200/500/1000 ms cycle lengths (CL) was performed, recording episodes of AF > 30 s. Co-localised RA tissue was snap frozen for RNA and protein extraction. Results Electrograms prolonged during AF (76.64 ± 29.35 ms) vs. NSR/pacing (p < 0.001). Compared to NSR, electrogram amplitude was reduced during AF and during pacing at 200 ms CL (p < 0.001). Electrogram DF was significantly lower in AF (75.87 ± 23.63 Hz) vs. NSR (89.33 ± 25.99 Hz) (p < 0.05), and NSR DF higher in AF inducible patients at the site of AF initiation (p < 0.05). Structurally, POAF atrial myocardium demonstrated reduced sarcolipin gene (p = 0.0080) and protein (p = 0.0242) expression vs. NSR. Phospholamban gene and protein expression was unchanged. SERCA2a protein expression remained unchanged, but MYH6 (p = 0.0297) and SERCA2A (p = 0.0343) gene expression was reduced in POAF. Conclusions Human atrial electrograms prolong and reduce in amplitude in induced peri-operative AF vs. NSR or pacing. In those sustaining AF, high DF sites in NSR may indicate ‘AF nests’. This electrical remodelling is accompanied by structural remodelling with altered expression of cardiomyocyte calcium handling detectable before POAF. These novel upstream substrate changes offer a novel mechanism and manifestation of human POAF.
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Affiliation(s)
- Junaid A B Zaman
- Myocardial Function, National Heart & Lung Institute, Hammersmith Hospital, Imperial College London, UK; Cardiovascular Medicine, Stanford University, Palo Alto, USA
| | - Leanne Harling
- Myocardial Function, National Heart & Lung Institute, Hammersmith Hospital, Imperial College London, UK; Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, UK; Department of Biomolecular Medicine, South Kensington Campus, Imperial College London, UK
| | - Hutan Ashrafian
- Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, UK; Department of Biomolecular Medicine, South Kensington Campus, Imperial College London, UK
| | - Ara Darzi
- Myocardial Function, National Heart & Lung Institute, Hammersmith Hospital, Imperial College London, UK
| | - Nigel Gooderham
- Department of Biomolecular Medicine, South Kensington Campus, Imperial College London, UK
| | - Thanos Athanasiou
- Myocardial Function, National Heart & Lung Institute, Hammersmith Hospital, Imperial College London, UK; Department of Surgery and Cancer, St Mary's Hospital, Imperial College London, UK.
| | - Nicholas S Peters
- Myocardial Function, National Heart & Lung Institute, Hammersmith Hospital, Imperial College London, UK
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Pachon M JC, Pachon M EI. Differential effects of ganglionic plexi ablation in a patient with neurally mediated syncope and intermittent atrioventricular block: a commentary. Europace 2016; 19:1-3. [DOI: 10.1093/europace/euw133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Singhal R, Lo LW, Lin YJL, Chang SL, Hu YF, Chao TF, Chung FP, Chiou CW, Tsao HM, Chen SA. Intrinsic Cardiac Autonomic Ganglionated Plexi within Epicardial Fats Modulate the Atrial Substrate Remodeling: Experiences with Atrial Fibrillation Patients Receiving Catheter Ablation. ACTA CARDIOLOGICA SINICA 2016; 32:174-84. [PMID: 27122948 PMCID: PMC4816916 DOI: 10.6515/acs20150427a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/27/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND A recent study reported the close relationship between high dominant frequent (DF) sites [atrial fibrillation (AF) nest] and the intrinsic cardiac autonomic nervous system. The aim of this study was to investigate the correlation between the regional distribution of epicardial fat and the properties of the biatrial substrates in AF patients. METHODS We studied 32 patients with paroxysmal (n = 23) and persistent (n = 9) AF. The epicardial fat volume around the left atrium (LA) was evaluated using 64-slice multidetector computed tomography and the topographic distribution of the fat volume was assessed. The biatrial DFs, voltages, and total activation times (TATs) were obtained during sinus rhythm. RESULTS Out of the 8 divided LA regions, a significant linear correlation existed between the LA fat and mean DF values in the right upper anterior LA, left upper anterior LA, right lower anterior LA, right upper posterior LA, left upper posterior LA, and left lower posterior LA. There was no significant correlation between the regional LA fat distribution and regional LA peak-to-peak bipolar voltage and TAT. During a mean follow-up of 17 ± 8 months, 22 of the 32 (69%) patients were free of AF. In the multivariate analysis, only the mean LA DF was found to be a significant predictor of recurrence. CONCLUSIONS There was a close association between the regional distribution of the LA epicardial fat and the atrial substrate manifesting high frequency during sinus rhythm (AF nest). Those nests were related to ablation outcome. Hence, epicardial fat may play a significant role in atrial substrate remodeling and thereby in the pathogenesis and maintenance of AF. KEY WORDS Atrial fibrillation • Dominant frequency • Epicardial fat • Nest • Recurrence.
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Affiliation(s)
- Rahul Singhal
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
| | - Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Yenn-Jiang Lin Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Shih-Lin Chang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Yu-Feng Hu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Tze-Fan Chao
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Fa-Po Chung
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Cheun-Wang Chiou
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
| | - Hsuan-Ming Tsao
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
- National Yang-Ming University Hospital, ILan, Taiwan
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, Taipei
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Lo LW, Chen SA. Hope or Hype – Does Cryoballoon Simplify Atrial Fibrillation Ablation Technique or Just Another Costly Toy? –. Circ J 2016; 80:1695-6. [DOI: 10.1253/circj.cj-16-0622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital
- Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University
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Simplified Method for Vagal Effect Evaluation in Cardiac Ablation and Electrophysiological Procedures. JACC Clin Electrophysiol 2015; 1:451-460. [DOI: 10.1016/j.jacep.2015.06.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/08/2015] [Accepted: 06/17/2015] [Indexed: 01/24/2023]
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18
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Zhang M, Wang X, Xie X, Wang Z, Liu X, Guan J, Wang W, Li Z, Wang J, Gao M, Hou Y. Long-Term Effects of Atrial Ganglionated Plexi Ablation on Function and Structure of Sinoatrial and Atrioventricular Node in Canine. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:1181-91. [PMID: 26172918 DOI: 10.1111/pace.12689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 06/19/2015] [Accepted: 06/28/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Long-term effects of ganglionated plexi (GP) ablation on sinoatrial node (SAN) and atrioventricular node (AVN) remain unclear. This study is to investigate the long-term effects of ablation of cardiac anterior right GP (ARGP) and inferior right GP (IRGP) on function and structure of SAN and AVN in canine. METHODS Thirty-two dogs were randomly divided into an operated group (n = 24) and sham-operated group (n = 8). ARGP and IRGP were ablated in operated group which was randomly divided into three subgroups according to the period of evaluation after operation (1 month, 6 months, 12 months). The functional and histological characteristics of SAN and AVN, as well as the expression of connexin (Cx) 43 and Cx 45 in SAN and AVN, were evaluated before and after ablation. RESULTS Resting heart rate was increased and AVN effective refractory period was prolonged and sinus node recovery time (SNRT) and corrected SNRT were shortened immediately after ablation. These changes were reverted to preablation level after 1 month. At 1 month, ventricular rate during atrial fibrillation was slowed, atria-His intervals were prolonged, and Cx43 and Cx45 expression in SAN and AVN were downregulated. At 6 months, all changes were reverted to preablation level. The histological characteristics of SAN and AVN did not change. CONCLUSION Ablation of ARGP and IRGP has short-term effects on function and structure of SAN and AVN rather than long-term effects, which suggests that ablation of ARGP and IRGP is safe. Atrioventricular conduction dysfunction after ablation may be related to downregulated Cx43 and Cx45 expression in AVN.
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Affiliation(s)
- Ming Zhang
- Department of Intensive Care Unit, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Ximin Wang
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Xinxing Xie
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Zhongsu Wang
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Xiaoyan Liu
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Juan Guan
- Department of Pharmacology, Shandong University School of Medicine, Jinan, China
| | - Weizong Wang
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Zhan Li
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Jiangrong Wang
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Mei Gao
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Yinglong Hou
- Department of Cardiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
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Dai M, Bao M, Liao J, Yu L, Tang Y, Huang H, Wang X, Huang C. Effects of low-level carotid baroreflex stimulation on atrial electrophysiology. J Interv Card Electrophysiol 2015; 43:111-9. [DOI: 10.1007/s10840-015-9976-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 01/20/2015] [Indexed: 11/28/2022]
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Brack KE. The heart's 'little brain' controlling cardiac function in the rabbit. Exp Physiol 2014; 100:348-53. [PMID: 25833107 PMCID: PMC4409095 DOI: 10.1113/expphysiol.2014.080168] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 09/19/2014] [Indexed: 12/31/2022]
Abstract
NEW FINDINGS What is the topic of this review? The topic of the review is the intrinsic cardiac nervous system in the rabbit. What advances does it highlight? The anatomy of rabbit intrinsic ganglia is similar to that of other species, including humans. Immunohistochemistry confirms the presence of cholinergic and adrenergic neurones, with a striking arrangement of neuronal nitric oxide synthase-positive cell bodies. Activation of atrial ganglia produces effects on local and remote regions. Heart disease is a primary cause of mortality in the developed world, and it is well recognized that neural mechanisms play an important role in many cardiac pathologies. The role of extrinsic autonomic nerves has traditionally attracted the most attention. However, there is a rich intrinsic innervation of the heart, including numerous cardiac ganglia (ganglionic plexuses), that has the potential to affect cardiac function independently as well as to influence the actions of the extrinsic nerves. To investigate this, an isolated, perfused, innervated rabbit Langendorff heart preparation was considered the best option. Although ganglionic plexuses have been well described for several species, there was no full description of the anatomy and histochemistry of rabbit hearts. To this end, rabbit intrinsic ganglia were located using acetylcholinesterase histology (n = 33 hearts). This revealed six generalized ganglionic regions, defined as a left neuronal complex above the left pulmonary vein, a right neuronal complex around the base of right cranial vein, three scattered in the dorsal right atrium and a region containing numerous ventricular ganglia located on the conus arteriosus. Using immunohistochemistry, neurons were found to contain choline acetyltransferase or tyrosine hydroxylase and/or neuronal nitric oxide synthase in differing amounts (choline acetyltransferase > tyrosine hydroxylase > neuronal nitric oxide synthase). The function of rabbit intrinsic ganglia was investigated using a bolus application of nicotine or electrical stimulation at each of the above sites whilst measuring heart rate and atrioventricular conduction. Nicotine applied to different ganglionic plexuses caused a bradycardia, a tachycardia or a mixture of the two, with the right atrial plexus producing the largest chronotropic responses. Electrical stimulation at these sites induced only a bradycardia. Atrioventricular conduction was modestly changed by nicotine, the main response being a prolongation. Electrical stimulation produced significant prolongation of atrioventricular conduction, particularly when the right neuronal complex was stimulated. These studies show that the intrinsic plexuses of the heart are important and could be crucial for understanding impairments of cardiac function. Additionally, they provide a strong basis from which to progress using the isolated, innervated rabbit heart preparation.
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Affiliation(s)
- Kieran E Brack
- Department of Cardiovascular Sciences, Cardiology Group, Glenfield Hospital, University of Leicester, UK; Leicester NIHR Biomedical Research Unit in Cardiovascular Disease, Glenfield Hospital, Leicester, UK
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