title: Functional properties of the superior vena cava (SVC)-aorta ganglionated plexus: evidence suggesting an autonomic basis for rapid SVC firing.
abstract: BACKGROUND
  the mechanism underlying spontaneous rapid superior vena cava (SVC) firing that initiates atrial fibrillation (AF) remains poorly understood. We investigated the role of the SVC-aorta-ganglionated plexus (SVC-Ao-GP) in AF initiated by rapid firing from the SVC.
  
  
  RESULTS
  in 42 dogs, a circular catheter was positioned above the SVC-atrial junction. Multielectrode catheters were sutured on atria, atrial appendages and pulmonary veins. The effective refractory period (ERP) and window of vulnerability (WOV) for AF were measured at all sites in the baseline state, during cervical vagosympathetic trunk stimulation and during SVC-Ao-GP stimulation, before and after SVC-Ao-GP ablation. AF inducibility was also assessed by delivering high-frequency stimulation (HFS) within myocardial refractory period to the SVC before and after SVC-Ao-GP ablation. HFS applied to the SVC-Ao-GP slowed the sinus rate and/or atrioventricular conduction. HFS of the SVC-Ao-GP induced more significant shortening of ERP and a greater increase in WOV at the SVC than other sites. Ablation of the SVC-Ao-GP significantly increased the baseline ERP and decreased the baseline WOV only at the SVC. AF induced at the SVC by HFS during refractoriness was eliminated by ablation of the SVC-Ao-GP but was not altered by ablation of the 4 major atrial GP. Direct injection of acetylcholine into the SVC-Ao-GP initiated rapid firing from the SVC in every case.
  
  
  CONCLUSIONS
  the SVC-Ao-GP preferentially modulates the electrophysiological function of the SVC sleeves and may contribute to rapid firing from the SVC.
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Zhibing
authors.initials: Z
authors.lastname: Lu
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Scherlag
authors.forename: Guodong
authors.initials: G
authors.lastname: Niu
authors.forename: Jiaxiong
authors.initials: J
authors.lastname: Lin
authors.forename: Kar-Ming
authors.initials: KM
authors.lastname: Fung
authors.forename: Lichao
authors.initials: L
authors.lastname: Zhao
authors.forename: Lilei
authors.initials: L
authors.lastname: Yu
authors.forename: Warren M
authors.initials: WM
authors.lastname: Jackman
authors.forename: Ralph
authors.initials: R
authors.lastname: Lazzara
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Sunny S
authors.initials: SS
authors.lastname: Po
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001013:Aorta, Thoracic / Q000294:innervation / Q000502:physiology*; D004285:Dogs; D005725:Ganglia, Autonomic / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D014683:Vena Cava, Superior / Q000502:physiology*