Targets and End Points in Cardiac Autonomic Denervation Procedures

Area of Science:

• Cardiology
• Electrophysiology
• Autonomic Nervous System

Background:

• Autonomic denervation is an alternative treatment for symptomatic bradycardia.
• Current procedures lack consensus on critical targets and endpoints.
• This study aimed to identify immediate endpoints and critical atrial regions for vagal denervation.

Purpose of the Study:

• To identify immediate procedural endpoints for vagal denervation.
• To determine critical atrial regions responsible for vagal denervation.
• To evaluate the effectiveness of radiofrequency ablation in modifying autonomic function.

Main Methods:

• 14 patients with cardioinhibitory syncope underwent autonomic denervation via radiofrequency ablation.
• Anatomic mapping of ganglionated plexuses was performed.
• Heart rate, sinus node recovery time, Wenckebach cycle length, and atrial-His interval were measured before and after ablation.

Main Results:

• Significant shortening of R-R interval (P=0.0009), Wenckebach cycle length (P=0.0009), and AH intervals (P=0.0014) was observed post-ablation.
• Heart rate increased by 23.8±12.5%, with significant shortening in Wenckebach cycle length (18.1±11%) and AH interval (24.6±19%).
• Targeting specific sites on the interatrial septum (left or right) accounted for ≥80% of the observed R-R and AH interval shortening.

Conclusions:

• Targeting specific interatrial septum sites improves heart rate and atrioventricular nodal conduction, crucial for vagal attenuation.
• Shortening of R-R interval, Wenckebach cycle length, and AH interval, coupled with a negative atropine response, serve as effective immediate endpoints.