Comparison of the Efficacy and Safety of Cardioneuroablation to Permanent Pacing in Patients With an Implanted Pacemaker for Symptomatic Bradycardia.

Background Sinus node dysfunction (SND) and atrioventricular block (AVB) are significant diagnostic and therapeutic problems. The primary method of their treatment is cardiac pacemaker implantation (PM). Although PM remains the main therapeutic approach for most patients with SND/AVB, long-term PM therapy can be associated with various limitations, complications, and the need for device and electrode replacement. There is increasing evidence for the effectiveness of an alternative approach to functional bradycardia associated with excessive vagal activation - cardioneuroablation (CNA). The method leads to the alleviation or complete resolution of bradycardia symptoms, as well as reflex syncope, providing an opportunity to discontinue PM therapy. Primary aims 1.Evaluation of the efficacy and safety of CNA as a therapy allowing for discontinuation of PM therapy in patients with SND or AVB. Secondary aims 1. Evaluation of the efficacy and safety of CNA as a therapy allowing for the optimization of PM therapy in patients with SND and AVB. 2. Development of a diagnostic algorithm allowing for the identification of patients with SND and/or AVB suitable for CNA and discontinuation of PM and TLE therapy. 3. In addition, blood samples will be collected for future analysis and biobanking. Methodology Inclusion criteria 1. Patients up to 50 years old who underwent pacemaker implantation due to sinus node and/or atrioventricular node dysfunction 2. Positive response to atropine test 3. Age between 18-65 years 4. Signed informed consent to participate in the study Exclusion criteria 1. Own heart rate \<30/min 2. Fainting after pacemaker therapy initiation 3. Persistent and sustained atrial fibrillation 4. History of myocarditis 5. History of myocardial infarction 6. History of cardiac surgery 7. History of ablation procedures 8. Congenital heart defects 9. Congenital atrioventricular block 10. Neuromuscular and neurodegenerative diseases 11. Indications for expanding th