Bradyarrhythmias are conditions where the heart beats too slowly, causing symptoms like dizziness, fainting, and fatigue. In some patients, these slow heart rhythms are caused by overactivity of the vagus nerve (the part of the nervous system that slows the heart down).
Cardioneuroablation (CNA) is a catheter-based procedure that targets and reduces the effect of these overactive nerves on the heart. It is an alternative to permanent pacemaker implantation, especially for younger patients.
Traditionally, CNA is performed using radiofrequency (RF) energy to create small burns in specific areas of the heart. This study investigates whether focal cryoablation (freezing technology using the Freezor™ Xtra catheter) is as safe and effective as standard RF ablation for CNA.
This is a prospective, non-randomized study. Participants will receive either RF ablation (N=30) or cryoablation (N=30). The study will evaluate the recurrence of slow heart rhythms and fainting episodes, as well as any complications, over 12 months of follow-up.
Age 18 to 60 years;
Symptomatic bradycardia (sinus bradycardia or bradycardia due to atrioventricular block, including transient);
Severe asymptomatic sinus bradycardia (heart rate less than 30 beats per minute);
Transient second- or third-degree atrioventricular block;
Chronic antiarrhythmic drug therapy (ongoing);
Presence of implanted pacemaker, cardiac resynchronization therapy device, or implantable cardioverter-defibrillator;
Bradyarrhythmia secondary to medications;
Bradyarrhythmia secondary to electrolyte imbalance (hyperkalemia);
Parallel
Focal Cryoablation
Procedure/SurgeryFocal cryoablation of right atrial ganglionated plexi using Freezor™ Xtra 6mm catheter (Medtronic) at -75°C for 240 seconds per application. 3-5 applications per GP zone. Positioned by fluoroscopy and impedance-based tracking in EnSite™ X system.
Radiofrequency Catheter Ablation
Procedure/SurgeryRadiofrequency ablation of right atrial ganglionated plexi using TactiFlex™ SE catheter (Abbott) with power up to 45W, temperature 50°C, target AI 45, with irrigation. 3-5 applications per GP zone. Guided by EnSite™ X mapping system and spectral analysis (OTNF).
Recurrence of Bradyarrhythmia or Syncope
Documented recurrence of symptomatic bradyarrhythmia (sinus bradycardia \<40 bpm, pause \>3 sec, AV block) or syncope confirmed by ECG or Holter
Pericardial Effusion or Hemopericardium
Pericardial effusion or hemopericardium requiring intervention, confirmed by echocardiography
Inappropriate Sinus Tachycardia
Sustained sinus tachycardia \>100 bpm without cause, requiring beta-blocker therapy
Vascular Access Complications
Hematoma, pseudoaneurysm, or AV fistula requiring treatment, confirmed by ultrasound
Change in Minimum Heart Rate
Absolute change in minimum heart rate (bpm) on 24-hour Holter from baseline to 6 months
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