Targets and End Points in Cardiac Autonomic Denervation Procedures

Abstract

Background-Autonomic denervation is an alternative approach for patients with symptomatic bradycardia. No consensus exists on the critical targets and end points of the procedure. The aim of this study was to identify immediate end points and critical atrial regions responsible for vagal denervation. Methods and Results-We enrolled 14 patients (50% men; age: 34.0±13.8 years) with cardioinhibitory syncope, advanced atrioventricular block or sinus arrest, and no structural heart disease. Anatomic mapping of ganglionated plexuses was performed, followed by radiofrequency ablation. Heart rate, sinus node recovery time, Wenckebach cycle length, and atrial-His (AH) interval were measured before and after every radiofrequency pulse. Wilcoxon signed-rank test was used for comparison. Significant shortening of the R-R interval (P=0.0009), Wenckebach cycle length (P=0.0009), and AH intervals (P=0.0014) was observed after ablation. The heart rate elevation was 23.8±12.5%, and the Wenckebach cycle length and AH interval shortening was 18.1±11% and 24.6±19%, respectively. Atropine bolus injection (0.04 mg/kg) did not increase heart rate further. Targeting a single spot of the left side (64% of the patients) or right side (36%) of the interatrial septum was observed to be responsible for ≥80% of the final R-R and AH interval shortening during ablation. Conclusions-Targeting specific sites of the interatrial septum is followed by an increase in heart rate and atrioventricular nodal conduction properties and might be critical for vagal attenuation. The R-R interval, Wenckebach cycle length, and AH interval shortening, associated with a negative response to atropine, could be considered immediate end points of the procedure.

Respiratory sinus arrhythmia is reduced after pulmonary vein isolation in patients with paroxysmal atrial fibrillation

“…However, RSA is a strong physiological signal and the marked changes in HR, HRV, and RSA following PVI support our study design. This is in line with another study having investigated targets and end points in cardiac autonomic denervation procedures in 14 patients including right and left atrial procedures [47].…”

“…Currently, PVI-induced changes are mostly assessed using specific parameters measured during the ablation procedure. Changes in HR, in the cycle length at which 1 : 1 conduction over the atrioventricular node stops (Wenckebach cycle length) and in the interval describing the time between the first atrial and His bundle deflection (AH interval), associated with a negative response to atropine, have been considered as immediate end points of those procedures [47]. However, positioning of catheters is necessary to investigate these parameters, which might be influenced by sedation and pain medication during the procedure.…”

“…Targeted ablation of ganglionated plexi is under investigation for symptomatic bradycardia including cardioinhibitory syncope [46,47]. As the autonomic nervous system and ganglionated plexi are inevitably modulated during PVI, one might speculate whether intermittent bradycardia or left ventricular sympathetic control can be diminished by PVI.…”

The short‐term impact of the catheter ablation on noninvasive autonomic nervous system parameters in patients with paroxysmal atrial fibrillation

“…Although AFCA has emerged as an effective treatment of AF in selected patients, we should also keep in mind that most unspecified antral PVAI might also affect normal GP function. Whether the change in the ANS is desirable remains to be determined after AFCA in long‐term studies to understand the precision mechanism for individual AF patient to selectively target either vagal or sympathetic nerves during PVAI …”

Long-term Efficacy and Safety of Cardioneuroablation in Patients with Vagally Mediated Bradyarrhythmias

“…There is no well-designed study investigating long-term efficacy of CNA. In a previously published study, pacemaker was implanted in four (44%) of nine cases due to symptomatic AVB recurrence after CNA (13) . In the current work, longterm clinical success was detected in 5 (55.5%) of nine cases with AVB.…”