title: Transvenous stimulation of the renal sympathetic nerves increases systemic blood pressure: a potential new treatment option for neurocardiogenic syncope.
abstract: BACKGROUND
  Neurocardiogenic syncope (NCS) is a common and sometimes debilitating disorder, with no consistently effective treatment. NCS is due to a combination of bradycardia and vasodilation leading to syncope. Although pacemaker devices have been tried in treating the bradycardic aspect of NCS, no device-based therapy exists to treat the coexistent vasodilation that occurs. The renal sympathetic innervation has been the target of denervation to treat hypertension. We hypothesized that stimulation of the renal sympathetic nerves can increase blood pressure and counteract vasodilation in NCS.
  
  
  RESULTS
  High-frequency stimulation (800-900 pps, 10 V, 30-200 seconds) was performed using a quadripolar catheter in the renal vein of 7 dogs and 1 baboon. A significant increase in blood pressure (BP; mean [SD] systolic BP 117 [±28] vs. 128 [±33], diastolic BP 75 [±19] vs. 87 [±29] mmHg) was noted during the stimulation, which returned to baseline after cessation of stimulation. The mean increase in systolic and diastolic BP was 13.0 (±3.3) (P = 0.006) and 10.2 (±4.6) (P = 0.08), respectively.
  
  
  CONCLUSIONS
  We report the first ever study of feasibility and safety of high-frequency electrical stimulation of the renal sympathetic innervation to increase BP in animal models. This has potential applications in the treatment of hypotensive states such as NCS.
authors.affiliation: Department of Cardiovascular Diseases, Rochester, Minnesota, USA.
authors.forename: Malini
authors.initials: M
authors.lastname: Madhavan
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Desimone
authors.forename: Elisa
authors.initials: E
authors.lastname: Ebrille
authors.forename: Siva K
authors.initials: SK
authors.lastname: Mulpuru
authors.forename: Susan B
authors.initials: SB
authors.lastname: Mikell
authors.forename: Susan B
authors.initials: SB
authors.lastname: Johnson
authors.forename: Scott H
authors.initials: SH
authors.lastname: Suddendorf
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Ladewig
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Gilles
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Danielsen
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D004285:Dogs; D004599:Electric Stimulation Therapy / Q000379:methods*; D005240:Feasibility Studies; D007668:Kidney / Q000294:innervation* / Q000502:physiology*; D010215:Papio; D010525:Peripheral Nerves / Q000502:physiology*; D012082:Renal Veins / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D019462:Syncope, Vasovagal / Q000503:physiopathology* / Q000517:prevention & control
keywords: blood pressure; neurocardiogenic syncope; renal nerve stimulation; sympathetic nervous system; syncope