title: Lead design and initial applications of a new lead for long-term endovascular vagal stimulation.
abstract: BACKGROUND
  Vagal nerve stimulation (VNS) has negative chronotropic and dromotropic effects. We developed and tested an endovascular spiral vagal stimulation lead (ESVL) designed to follow the projection of the cardiac branches of the vagus nerve around the superior vena cava (SVC) to optimize VNS.
  
  
  METHODS
  ESVL contained six 5-mm coil electrodes, spaced 5-mm apart with a spiral guidewire to provide shape. The tightness and diameter of the guidewire were changed before each placement to simulate different lead designs. Various 2-, 3-, and 4-electrode combinations were used and several lead positions were tested each time. Each VNS protocol included 2-12 V, 15-second pulse trains at 20 Hz, with 2 ms pulse duration. A basket catheter (BC) was used as control and to approximate the initial VNS location. The VNS protocol was performed at the optimal location, using first the BC and then several ESVL configurations.
  
  
  RESULTS
  VNS caused a voltage-dependent decrease in heart rate (HR). Using the optimal ESVL configuration at 7 V, HR decreased by 30.4% (37.2 bpm) in dog no. 1 and 12.4% (16.6 bpm) in dog no. 2, versus 15.5% (16.6 bpm) and 16.7% (19.5 bpm) with the BC.
  
  
  CONCLUSIONS
  A new endovascular spiral lead that takes advantage of the anatomy of the cardiac branches of the vagus nerve in the SVC was developed. VNS using ESVL produced significant HR slowing at voltages slightly below the highest pulse generator output of 7.5 V, which may be suitable for long-term implantation.
authors.affiliation: St. Jude Medical, CRMD, Sunnyvale, California, USA. ynabutovsky@sjm.com
authors.forename: Yelena
authors.initials: Y
authors.lastname: Nabutovsky
authors.forename: Joseph
authors.initials: J
authors.lastname: Florio
authors.forename: Kevin
authors.initials: K
authors.lastname: Morgan
authors.forename: Warren M
authors.initials: WM
authors.lastname: Grill
authors.forename: Taraneh G
authors.initials: TG
authors.lastname: Farazi
mesh_terms: D000818:Animals; D004285:Dogs; D004599:Electric Stimulation Therapy / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D006339:Heart Rate; D014630:Vagus Nerve; D014683:Vena Cava, Superior / Q000294:innervation