title: Effects of electrical stimulation of carotid baroreflex and renal denervation on atrial electrophysiology.
abstract: BACKGROUND
  This study was designed to compare the effect of electrical baroreflex stimulation (BRS) at an intensity used in hypertensive patients and renal denervation (RDN) on atrial electrophysiology. BRS and RDN reduce blood pressure and global sympathetic drive in patients with resistant hypertension. Whereas RDN decreases sympathetic renal afferent nerve activity, leading to decreased central sympathetic drive, BRS modulates autonomic balance by activation of the baroreflex, resulting in both reduced sympathetic drive and increased vagal activation. Increased vagal tone potentially shortens atrial refractoriness resulting in a stabilization of reentry circuits perpetuating atrial fibrillation (AF).
  
  
  RESULTS
  In normotensive anesthetized pigs (n = 12), we compared the acute effect of BRS and RDN on blood pressure, atrial effective refractory period (AERP), and inducibility of AF. Electrical BRS was titrated to result in comparable heart rate and blood pressure reduction compared to irreversible RDN. BRS resulted in a rapid and pronounced shortening of AERP (from 162 ± 8 milliseconds to 117 ± 16 milliseconds, P = 0.001) associated with increased AF-inducibility from 0% to 82%. This shortening in AERP was completely reversible after stopping BRS. After administration of atropine, AF-inducibility during BRS was attenuated. Ventricular repolarization was not modulated by BRS. In RDN, AF was not inducible; however, it did not prevent BRS-induced shortening of AERP.
  
  
  CONCLUSIONS
  RDN and BRS resulting in comparable blood pressure and heart rate reductions differently influence atrial electrophysiology. Vagally mediated shortening of AERP, resulting in increased AF-inducibility, was observed with BRS but not with RDN.
authors: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg/Saar, Germany.
authors: Dominik
authors: D
authors: Linz
authors: Felix
authors: F
authors: Mahfoud
authors: Ulrich
authors: U
authors: Schotten
authors: Christian
authors: C
authors: Ukena
authors: Hans-Ruprecht
authors: HR
authors: Neuberger
authors: Klaus
authors: K
authors: Wirth
authors: Michael
authors: M
authors: Böhm
mesh_terms: D000818:Animals; D016275:Atrial Function / Q000502:physiology*; D017704:Baroreflex / Q000502:physiology*; D002339:Carotid Arteries / Q000502:physiology*; D007668:Kidney / Q000294:innervation* / Q000502:physiology*; D008297:Male; D010865:Pilot Projects; D013552:Swine; D013562:Sympathectomy / Q000379:methods*
keywords: atrial fibrillation; baroreflex stimulation; hypertension; renal denervation