Efficacy of Transcatheter Ablation of Ganglionic Plexuses (Cardioneuroablation) in Right Atrium in Patients With Asystolic Neuromediated Syncope
Phase: NA
Conditions: Neurally Mediated Syncope
Sponsor: Policlinico Casilino ASL RMB

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Study Protocol - Vers. 1-0 of March 30, 2021 
 
 
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GIMSI. 
 
 
 
Efficacy of transcatheter ablation of ganglionic 
plexuses (Cardioneuroablation) in right atrium in 
patients with asystolic neuromediated syncope 
 
Italian multicenter study sponsored by GIMSI 
Acronym: ItalianCNA 
 
Promoter 
GIMSI ASSOCIATION 
"Multidisciplinary Group for the Study of 
Syncope" 
VIA SASSONIA N. 30 
47924 RIMINI _ ITALY 
Principal Investigator 
Prof Leonardo Calò, Policlinico Casilino, 
Rome 
Study phase 
Phase 2 Interventional Study 
Version and date 
Version V1 _ March 30, 2021 
 
 

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Author 
 
 
Name: Prof Leonardo Caló 
Role: 
Coordinator 
Scientific
 
and Principal Investigator 
Signature: 
Date: 
 
 
 
Steering Committee 
 
 
Prof Leonardo Caló 
Coordinator 
Dr Alessio Borrelli 
Member 
Prof Michele Brignole 
Member 
Dr Ermenegildo de Ruvo 
Member 
Dr Marco Rebecchi 
Member 
Prof Stefano Strano 
Member 

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Summary 
Introduction and purpose of the study .................................................. 4 
Study design ......................................................................................... 4 
Inclusion criteria ................................................................................... 5 
Exclusion criteria ................................................................................... 6 
Ablative procedure ................................................................................ 6 
Follow up (study phase) ........................................................................ 6 
Endpoint ................................................................................................ 7 
Ancillary substudy (ancillary study): spectral analysis .......................... 7 
Sample calculation ................................................................................ 7 
Bibliography .......................................................................................... 8 
Appendix ............................................................................................. 10 
Mapping and Ablation procedure ...................................................... 10 
Patient questionnaire ....................................................................... 12 
 

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Introduction and purpose of the study 
 
Neuro-mediated cardioinhibitory syncope (SCNM) represents the most frequent 
form of syncope in the young population without apparent cardiac or neurological 
pathology (1,2). Although affected young patients have an excellent prognosis, their 
quality of life can be seriously deteriorated by the frequency of episodes (2,3,4). 
Definitive cardiac pacing is an effective therapy and is recommended in patients >40 
years old (1,2,5,6); there are no trials in patients <40 years old. The general scientific 
consensus is that in younger patients the role of the pacemaker raises some concerns 
arising from the need for numerous replacements and possible ventricular remodeling 
induced by right ventricular pacing over time. 
In patients <40 years old with severe recurrent syncope, current practice is to 
implant loop recorders in order to document the dominant mechanism of syncope, 
cardioinhibitory or vasodepressor. In cases of asystolic syncope, in the absence of 
proven effective therapies, recently, transcatheter radiofrequency ablation of the 
anatomical site areas of the ganglionic plexuses in the right and left atrium has shown 
promising results, both in the short and long term regarding the treatment of 
cardioinhibitory reflex syncope (7,8,9,10,11,12,13,14). In Italy, ganglion plexus 
ablation, so-called cardioneuroablation (CNA) has been current practice in selected 
cases since 2012 at Policlinico Casilino (15) and the results have been published 
recently (13). The technique proposed by Caló et al (13), consists of ablation of the 
ganglionic plexuses of the right atrium. No center currently has sufficient case series 
to establish long-term efficacy and safety results, for which a multicenter 
interventional study is therefore needed. 
In view of these premises, the aim of the study will be to evaluate the efficacy 
and safety of NAC in patients with SCNM with ECG documentation of spontaneous 
asystolic episodes of reflex nature. 
 
 
Study design 
 
ItalianCNA is a multicenter Italian interventional "proof of efficacy" clinical trial 
that aims to evaluate the incidence of asystolic pauses and heart rate in patients with 
SCNM who performed CNA after documentation of asystolic pauses on ECG monitoring 
by implantable loop recorder. 
The study is independent, "investigator-initiated," sponsored by a nonprofit 
scientific association called the Italian Multidisciplinary Group for the Study of Syncope 
(GIMSI). 

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Inclusion criteria 
• Age between 18 and 60 years 
• Patients with a clinical diagnosis of neuromediated syncope according to class I 
criteria of the ESC guidelines, Table 1 
• Clinical history of recurrent syncope (≥2 in the last year or ≥3 in the last 2 years), 
severe, not tolerated by the patient 
• Documentation of ≥2 asystolic pauses >3 sec daytime on ECG monitoring by 
implantable loop recorder (ILR), with or without syncope 
• Refusal by patient to perform pacemaker implantation 
 
Table 1. Diagnostic criteria of reflex syncope according to ESC guidelines (1,2) 
Recommendations 
Class 
Level 
Reflex syncope 
1. VVS is highly probable if syncope is precipitated by 
pain or fear or standing, and is associated with 
Typical progressive prodrome (pallor, sweating, 
nausea). 
I 
C 
2. Situational reflex syncope is highly probable if 
syncope occurs during or immediately after specific 
triggers. 
I 
C 
                 
         
          
   
        
         
       

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Tilt test is recommended but not mandatory. Patients with negative tilt test are also 
enrollable. It can be either positive or negative. 
 
 
Exclusion criteria 
 
• Absence of sinus dysfunction and atrioventricular node disease. 
• Absence of structural heart disease 
• Possible alternative diagnoses of syncope 
 
 
Ablative procedure 
The ablative procedure involves applying radiofrequency deliveries in the two 
Right atrium anatomical sites close to the two main ganglionic plexuses of the right 
atrium: 
- 
Inferior-posterior area (site of first ablation) corresponding to the right 
inferior atrial ganglion located between the inferior vena cava, coronary sinus 
ostium and near the atrioventricular node 
- 
Upper-posterior area (site of second ablation) corresponding to the right 
superior atrial ganglion located between the superior vena cava and the 
posterior surface of the right atrium 
The method of the ablative procedure is described in detail in the Appendix (see) 
 
Acute success is defined as: 
- 
Shortening of AH interval >20 ms, relative to baseline, persisting for 30 min, 
and/or Wenckebach point <500 ms at end of procedure 
plus 
- 
P-P interval <70% of basal P-P interval, or P-P interval <600 ms (calculated as 
the average of 10 consecutive cycles), after 10 min since the last delivery 
The procedure will be continued until the acute efficacy criteria are met. In case 
the procedure is terminated without having reached the target, this will be noted as 
"acute failure" 
 
Follow up (study phase) 
It consists of remote monitoring and quarterly questionnaire completed by the 
patient himself (see appendix). 
• 
Remote monitoring. Central, by an ad hoc established Single 
Laboratory. All episodes of asystole >3 sec and average monthly 
heart rate will be recorded 

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• 
Patient's self-administered questionnaire. The syncope follow-up 
questionnaire validated in the BioSync study (6) will be used. Every 3 
months the patient will send the questionnaire to the Single 
Laboratory. 
 
An "Adjudication Committee " consisting of 3 physicians not involved in the 
study will validate ECG events and questionnaire responses 
 
 
Endpoint 
Main analysis according to intention-to-treat principle. Exploratory 
subgroup analysis with acute success. 
 
Primary endpoint: Intrapatient comparison of monthly incidence of episodes. 
asystolic >3 sec before and after CNA 
Secondary endpoints: 
• 
Intrapatient comparison of mean heart rate, before and after CNA 
• 
Intrapatient comparison of monthly incidence of (pre)syncopal 
episodes before and after CNA 
• 
Intrapatient comparison of beat-to-beat variability of heart rate in the 
short term (spectral analysis) before and after CNA (limited to 
auxiliary HRV study) 
 
 
Ancillary substudy (ancillary study): spectral 
analysis 
It consists of acquiring digitized ECG monotrace for 5 minutes the day before and 
the day after the procedure using surface ECG recording equipment provided free of 
charge by the promoter. Spectral analysis of the oscillatory components of R-R 
interval variability will be performed on the ECG trace. This study is optional 
 
 
Sample calculation 
Considering clinically effective a 50% reduction in the monthly incidence of 
asystole episodes of >3 sec, which before the ablative procedure is assumed to be 
0.82±0.67 (16), with 24 patients undergoing ablation, the null hypothesis (Ho: null 
difference in asystole incidence pre/post-ablation) can be rejected with 80% statistical 
power at a two-sided t-test with alpha error 0.05. 

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Bibliography 
1. Moya, A., Sutton, R., Ammirati, F., Blanc, J. J., Brignole, M., Dahm, J. B., Task 
Force for the Diagnosis and Management of Syncope, European Society of 
Cardiology (ESC), European Heart Rhythm Association (EHRA), Heart Failure 
Association (HFA), & Heart Rhythm Society (HRS). (2009). Guidelines for the 
diagnosis and management of syncope (version 2009). European Heart Journal, 
30(21), 2631-2671. 
2. Michele Brignole, et al. 2018 ESC Guidelines for the diagnosis and management 
of syncope. European Heart Journal, Volume 39, Issue 21, 01 June 2018, Pages 
1883–1948, https://doi.org/10.1093/eurheartj/ehy037 
3. Sutton, R., & Petersen, M. E. (1995). The clinical spectrum of neurocardiogenic 
syncope. Journal of Cardiovascular Electrophysiology, 6(7), 569-576. 
4. Soteriades, E. S., Evans, J. C., Larson, M. G., Chen, M. H., Chen, L., Benjamin, 
E. J., et al. (2002). Incidence and prognosis of syncope. The New England 
Journal of Medicine, 347(12), 878- 885. 
5. Brignole M, Menozzi C, Moya A, Andresen D, Blanc JJ, Krahn AD, et al. (2011); 
Pacemaker therapy in patients with neurally mediated syncope and documented 
asystole: Third International Study on Syncope of Uncertain Etiology (ISSUE-3): 
a randomized trial. Circulation. 125(21):2566-71. 
6. Brignole M, Russo V, Arabia F, Oliveira M, Pedrote A, Aerts A, Rapacciuolo A, 
Boveda S, Deharo JC, Maglia G, Nigro G, Giacopelli D, Gargaro A, Tomaino M; 
BioSync CLS trial Investigators. Cardiac pacing in severe recurrent reflex 
syncope and tilt-induced asystole. Eur Heart J. 2020 Dec 5;42(5):508-16. doi: 
10.1093/eurheartj/ehaa936. Epub ahead of print. PMID: 33279955; PMCID: 
PMC7857694. 
7. Pachon, J. C., Pachon, E. I., Pachon, J. C., Lobo, T. J., Pachon, M. Z., Vargas, R. 
N. A., et al. (2005). "Cardioneuroablation"-new treatment for neurocardiogenic 
syncope, functional AV block and sinus dysfunction using catheter RF-ablation. 
Europace, 7(1), 1- 13. 
8. Scanavacca, M., Hachul, D., Pisani C., & Sosa E. (2009). Selective vagal 
denervation of the sinus and atrioventricular nodes, guided by vagal reflexes 
induced by high frequency stimulation, to treat refractory neurally mediated 
syncope. Journal of Cardiovascular Electrophysiology, 20(5), 558-563. 
9. Armour, J. A., Murphy, D. A., Yuan, B. X., Macdonald, S., & Hopkins, D. A. 
(1997). Gross and microscopic anatomy of the human intrinsic cardiac nervous 
system. Anatomical Record, 247 (2), 289-298. 
10. Singh, S., Johnson, P. I., Lee, R. E., Orfei, E., Lonchyna, V. A., Sullivan, H. J., 
et al. (1996). Topography of cardiac ganglia in the adult human heart. The 
Journal of Thoracic and Cardiovascular Surgery, 112(4), 943-953. 
11. Chiou, C. W., Eble, J. N., & Zipes, D. P. (1997). Efferent vagal innervations of 
the canine atria and sinus and atrio-ventricular nodes. The third fat pad. 
Circulation, 95(11), 2573-2584. 

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12. Po, S. S., Nakagawa, H., & Jackman, W. M. (2009). Localization of left atrial 
ganglionated plexi in patients with atrial fibrillation. Journal of Cardiovascular 
Electrophysiology, 20(10), 1186-1189. 
13. Calò L, Rebecchi M, Sette A, et al. Catheter ablation of right atrial ganglionated 
plexi to treat cardioinhibitory neurocardiogenic syncope: a long-term follow-up 
prospective 
study. 
J 
Int 
Cardiac 
Electrophysiol 
2020 
(July 
27) 
doi.org/10.1007/s10840-020-00840-9 published ahead of print 
14. Debruyne P, Rossenbacker T, Collienne C, Roosen J, Ector B, Janssens L, 
Charlier F, Vankelecom B, Dewilde W, Wijns W. Unifocal Right-Sided Ablation 
Treatment for Neurally Mediated Syncope and Functional Sinus Node 
Dysfunction 
Under 
Computed 
Tomographic 
Guidance. 
Circ 
Arrhythm 
Electrophysiol. 2018 Sep;11(9):e006604. doi: 10.1161/CIRCEP.118.006604. 
PMID: 30354289. 
15. Rebecchi M, de Ruvo E, Strano S, Sciarra L, Golia P, Martino A, Calò L. 
Ganglionated 
plexi 
ablation 
in 
right 
atrium 
to 
treat 
cardioinhibitory 
neurocardiogenic syncope. 
J Interv Card Electrophysiol. 2012 Sep;34(3):231-5 
16. Brignole M, Iori M, Solari D, et al. Efficacy of theophylline in patients with 
syncope without prodromes with normal heart and normal ECG Int J Cardiol 
2019;289:70-73 

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Appendix 
 
Mapping and Ablation procedure 
The day before ablation procedure, an ECG is performed in resting conditions and 
after intravenous administration of atropine. Atropine test is carried out in fasting 
state with up to 2 mg intravenous atropine sulfate, under continuous ECG recording 
for 30 minutes (two injections of 1 mg atropine with an interval of 5 minutes). A 
decrease more than 25% in PP interval is accepted as a positive response. 
Mapping and ablation are performed under mild sedation and local anesthesia. 
Three right femoral vein punctures are performed: a) a decapolar catheter is inserted 
into the coronary sinus; b) a quadripolar catheter is positioned in the hisian region; c) 
and a quadripolar deflectable irrigated tip ablation catheter (Navistar SmartTouch, 
Biosense Webster, Inc or Tacticath, Abbott Inc) is used for mapping and ablation. 
Electroanatomical mapping of the right atrium (RA) is performed by means of CARTO 
3™ (Biosense Webster, Inc) or by EnSite Precision (Abbott Inc). A three-dimensional 
anatomical mapping of the RA is performed, during which volume data are recorded 
continuously during manipulation of the catheter inside the RA. From the outer surface 
of the volume data acquired, the system generates a surface reconstruction. Tagging 
the phrenic nerve capture points on the lateral RA allowed us to map the phrenic 
nerve course. The parameters considered during basal electrophysiological study are: 
basal cycle length, AH interval and Wenckebach cycle length. 
The ablation procedure consists of RF delivering (RF energy at 43°, 30-35 W for 
30-60 s) at right atrial anatomic sites where the underlying presence of GP clusters is 
regarded as highly probable: 1) the inferior-posterior area (first ablation site): 
inferior right GP placed between inferior vena cava, coronary sinus ostium and near 
the atrio-ventricular groove, 2) the superior-posterior area (second ablation 
site): superior right atrial GP, adjacent to the junction of the superior vena cava and 
the posterior surface of RA. The identification of the anatomical target is improved by 
the 
presence of high amplitude fractionated electrograms (HAFE, number of deflections
 
4, amplitude 
0.7 mV and duration 
40ms) by using of a single beat analysis in order 
toquantify number of signal deflections and total activation time and differentiating 
them by normal electrograms (number of deflections < 4 or duration < 40 ms). 
Care is taken to avoid ablations in the proximity of the mapped course of the 
phrenic nerve. To avoid phrenic nerve injury, high amplitude stimulation is performed 
just before radiofrequency delivery to the superior right atrial GP. 
Considering that the exact anatomic borders of GP clusters are unknown, an 
expanded number of RF applications are delivered in order to form a cloud-like shape 
ablation surrounding the HAFE tags. An irrigated tip catheter using a contact force >5 
g is recommended. P-P interval is carefully monitored. The duration of each single 
ablation is generally prolonged for at least 30 seconds after stabilization of P-P 
intervals but does not exceed 60 seconds at the same location. RF applications are 
interrupted if no significant shortening of the P-P interval is observed within 30 
seconds or an ablation index target value of >350-500 or lesion stability index target 

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value of 4-5.5 is achieved. Points acquired during ablation are annotated by 2 mm 
tags. 

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It is recommended that ablation is continued until atrial electrical activity (HAFE) 
is significantly reduced (peak to peak bipolar electrogram < 0.05 mV) and vagal reflex 
disappears if present. 
It is also recommended, at the end of ablation procedure, to confirm the 
significant reduction of atrial electrical activity by using of a final voltage map and by 
showing inability to capture at high output. In addition, a backup stimulation in the 
right ventricle is performed through a quadripolar catheter in case of prolonged 
asystolic response evoked during RF. 
Basal cycle length, AH and Wenckebach cycle length are reassessed after RF 
ablation. 
After catheter removal, atropine 2 mg (1m + 1m 5 min later) is administrated 
intravenously > 30 minutes after the last ablation. 
Acute procedural success is defined as: 
• 
Persistent AH shortening > 20 msec and/or persistent reduction in 
Wenckebach point cycle length < 500 msec 
and 
• 
Post RF P-P interval <70% of the baseline procedural P-P interval or 
P- P interval >600 msec after 10 minutes of waiting time (as mean 
value of 10 consecutive cycles) 
Post RF inappropriate sinus tachycardia is temporarily treated with beta-blockers 
or ivabradine. 

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Patient questionnaire 
 
PATIENT QUESTIONNAIRE 
 
Patient ID: 
CNA -------------  
 
 
 
 
Date of completion (dd-mm-yyyyy):  
 
-  
 
-  
 
 
 
 
 
 
QUESTIONNAIRE 
(a) Did you completely lose 
consciousness for a moment? 
(syncope, fainting) 
Yes 
No 
If yes, do you remember the 
date it happened? Go to 
question (c) 
dd-mm-yyyyy:  
 
-  
 
-  
 
 
 
 
(b) Or, alternatively, did you 
recognize any premonitory 
symptoms of impending loss 
of consciousness, without 
being followed by complete 
loss of consciousness? 
(presyncope) 
Yes 
No 
(Note. Answers to (a) and (b) should not both 
be "Yes.") 
If yes, do you remember the 
date when it happened? 
dd-mm-yyyyy:  
 
-  
 
-  
 
 
 
 
(c) Was the episode 
characterized by rapid 
initiation, short duration, and 
complete spontaneous 
recovery? 
Yes 
No 
(d) Is the episode similar to 
those you have had before? 
Yes 
No 
(e) Did you have time to stop 
and lie down/sit down? 
Yes 
No 
(f) Did other people witness 
the episode? 
Yes 
No 

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(g) Where did the episode 
happen? 
At home 
At work 
On public transportation 
On a private transportation vehicle, while 
driving. 
On a private transport, but I was not 
driving 
As I walked down the street Other, 
please specify: 
(h) What were you doing 
immediately before the 
event? 
I was lying 
I was 
sitting I 
was 
standing 
I was sitting down from a lying position 
I was standing up from a lying position 
I was eating 
I was under emotional stress Other, 
please specify: 
(i) Did you experience any 
trauma as a result of the 
event? 
Yes 
No 
(j) Did you go to the 
emergency room because of 
the trauma? 
Yes 
No 
(k) Were you hospitalized 
because of the trauma? 
Yes 
No