Comparison of Focal Cryoablation vs. Radiofrequency Cardioneuroablation for Bradyarrhythmias

Summary

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.

Eligibility

Inclusion Criteria:

* 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;
* Persistent second-degree atrioventricular block;
* Rhythm pauses greater than 6 seconds;
* Recurrent syncope or presyncope with documented association with bradycardia (without trauma);
* Positive response to atropine (heart rate increase ≥25% from baseline or \>90 beats per minute) OR positive response to exercise (heart rate increase ≥25% from baseline or \>90 beats per minute, OR conversion of second- or third-degree atrioventricular block to first-degree block or complete normalization of atrioventricular conduction during sinus rhythm);

Exclusion Criteria:

* 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);
* Bradyarrhythmia secondary to hypothyroidism;
* Bradyarrhythmia secondary to obstructive sleep apnea syndrome;
* Absence of response to pharmacological denervation (no heart rate increase after atropine administration up to maximum dose of 0.2 mg/kg);
* Clinically significant coronary artery disease;
* Post-myocardial infarction cardiosclerosis;
* Hemodynamically significant congenital heart disease (including surgically corrected);
* Stable ventricular tachycardia in the setting of bradycardia;
* History of stroke or transient ischemic attack;
* Prior open-heart surgery;
* Prior catheter-based coronary artery intervention or percutaneous coronary intervention;
* Pregnancy or breastfeeding; Age less than 18 years Age greater than 60 years

Conditions5

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