Cardioneuroablation for Bradyarrhythmia

Catheter ablation is a common treatment for cardiac arrhythmias. Some patients with AF ablation or AVNRT experience acceleration of sinus rhythm, the most likely cause of which is modification of autonomic tone caused by inadvertent damage to intramural autonomic ganglia and fibers. Intentional damage to these plexuses has become known as cardioneuroablation (CNA) and is currently used in patients with tachycardia-bradycardia syndrome, vegetatively caused sinus node dysfunction and atrioventricular conduction disorders, vasovagal syncopal conditions developing in a cardioinhibitory type.

It is suggested that in some patients CNA may become an alternative to permanent pacemaker for the treatment of symptomatic bradyarrhythmias.

This is a multicentre randomised clinical study evaluating the efficacy of cardioneuroablation for severe bradycardia due to sinus node dysfunction and/or atrioventricular nide dysfunction versus a sham procedure.

• Ganglionated plexi ablation (Procedure): Through access in the femoral vein, a mapping or ablation-mapping catheter is inserted into the right atrium, and a three-dimensional reconstruction of the right atrium is performed using an electroanatomic mapping system. The inferior and superior vena cava, the coronary sinus are indicated. Then a transeptal puncture is performed using a transeptal introducer and a needle for transeptal puncture under fluoroscopic control. A three-dimensional reconstruction of the left atrium is performed using an electroanatomic mapping system. During or immediately after the creation of three-dimensional maps of both atria, areas of the typical concentration of ganglion plexuses (GP) are ablated using radiofrequency applications (30-50 Watts, 10-40 s each point). Ablated points are annotated on the three-dimensional map. GPs ablation zones are about 0.5 x 1.0 cm in size.
• Electrophysiological study (Diagnostic test): Through access in the femoral vein, a diagnostic catheter is inserted in the area of the coronary sinus under fluoroscopic control. The effective refractory period (ERP) of the atria will be measured according to the method adopted in clinical practice, namely: using a ten-pole diagnostic electrode installed in the coronary sinus, a series of eight electrical pulses with the same amplitude and frequency is applied to the atrial myocardium. Then the ninth pulse is applied with a gradual decrease in the time interval until the absence of an atrial myocardium response to the pulse is registered. The cycle of an additional, ninth pulse, in which the atrial myocardium did not respond to an electrical impulse, is considered an atrial ERP.

Primary outcomes

• Implantation of a permanent cardiac pacemaker [12 months post procedure]: Once there is a recurrence of documented symptomatic bradycardia, a permanent pacemaker implantation is considered

Secondary outcomes

• Complications of cardioneuroablation [30 days post procedure]: Cardiac tamponade, pericardial effusion >10 mm, esophageal damage, stroke or transient ischemic event, severe groin hematoma (hemoglobin level drop >20%), atriovenous fistula in the groin
• Presence of symptomatic or asymptomatic rhythm pauses >6 seconds [12 months post procedure]: As detected by ECG monitoring
• The presence of symptomatic or asymptomatic sinus bradycardia with an average heart rate <40 beats/min in the daytime [12 months post procedure]: As detected by ECG monitoring
• Transient or permanent atrioventricular block [12 months post procedure]: As detected by ECG monitoring
• Orthostatic hypotension and/or bradycardia during passive orthostasis test [12 months post procedure]: Tilt-testing
• Sinus tachycardia after cardioneuroablation [30 days post procedure]: As detected by ECG monitoring, defined as daytime mean heart rate >100 bpm
• Implantation of a pacemaker by 24 months after randomization [24 months post procedure]: Once there is a recurrence of documented symptomatic bradycardia, a permanent pacemaker implantation is considered

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

1. Any of the following variants of bradyarrhythmia in patients aged 18-65 years:

   (1.1.) Symptomatic sinus bradycardia or bradycardia due to atrioventricular blockade, including transient.

   (1.2.) Severe asymptomatic sinus bradycardia with a rhythm frequency of <30 beats/min.

   (1.3.) Transient atrioventricular block of II-III degree or permanent block of II degree.

   (1.4.) Repeated fainting or pre-fainting states with a proven association with bradycardia (without injury).

   (1.5.) Rhythm pauses >6 seconds.

   In combination with the following two criteria:
2. Positive reaction to physical activity and/or atropine test:

   (2.1.) Increase in sinus rhythm frequency ≥25% or >90 beats/min. (2.2.) The transition of atrioventricular blockade of the II-III degree to the 1st degree or complete normalization of atrioventricular conduction at the sinus rhythm.
3. Sinus rhythm at the time of switching on

Exclusion Criteria:

1. Anamnesis of injury during syncopation due to bradycardia, except in the case when the patient refused to implant an electrocardiostimulator for his own reasons in writing;
2. Constant intake of antiarrhythmic drugs (for PVC, AF, etc.);
3. The presence of an implanted pacemaker, a heart contractility modulation device, a cardioverter defibrillator;
4. Drug-induced sinus bradycardia and/or atrioventricular block;
5. Bradycardia due to electrolyte imbalance (e.g. hyperkalemia);
6. Bradycardia due to hypothyroidism or other reversible conditions;
7. No reaction to the administration of atropine (up to a maximum dose of 0.2 mg / kg);
8. Proven association of bradyarrhythmia with episodes of apnea/hypopnea in obstructive sleep apnea syndrome;
9. Clinically significant coronary artery disease;
10. Postinfarction cardiosclerosis;
11. Hemodynamically significant congenital heart defects, including operated ones;
12. Stroke or transient ischemic attack <3 months;
13. Open heart surgery in the anamnesis;
14. Catheter interventions on coronary arteries or for cardiac arrhythmias <3 days;
15. Conditions after percutaneous coronary angioplasty <3 months;
16. Anamnesis of stable ventricular tachycardia on the background of bradycardia;
17. Pregnancy or breastfeeding period

• Evgeny Mikhaylov, Prof., Principal investigator, Almazov National Medical Research Centre