title: 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.
  
  
  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.
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Esteban W
authors.initials: EW
authors.lastname: Rivarola
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Denise
authors.initials: D
authors.lastname: Hachul
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Tan
authors.initials: T
authors.lastname: Wu
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Pisani
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Carina
authors.initials: C
authors.lastname: Hardy
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Raimundi
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Sissy
authors.initials: S
authors.lastname: Melo
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: Darrieux
authors.affiliation: From the Unidade Clínica de Arritmia, Heart Institute, University of São Paulo Medical School, Brazil. mauricio.scanavacca@incor.usp.br.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Scanavacca
mesh_terms: D000293:Adolescent; D000328:Adult; D054537:Atrioventricular Block / Q000601:surgery; D017763:Autonomic Denervation / Q000379:methods*; D001919:Bradycardia / Q000601:surgery*; D004562:Electrocardiography; D023381:Endpoint Determination; D005260:Female; D006329:Heart Conduction System / Q000601:surgery*; D006339:Heart Rate; D006346:Heart Septum / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012849:Sinoatrial Node / Q000601:surgery; D019462:Syncope, Vasovagal / Q000601:surgery; D016896:Treatment Outcome
keywords: atrial fibrillation; autonomic nervous system; bradycardia; denervation; reflex