title: Low-Level But Not High-Level Baroreceptor Stimulation Inhibits Atrial Fibrillation in a Pig Model of Sleep Apnea.
abstract: Obstructive sleep apnea (OSA) increases susceptibility to atrial fibrillation (AF) by a combined sympatho-vagal hyperactivation. The purpose of this study was to investigate the effect of autonomic nervous system modulation by low-level baroreceptor stimulation (LL-BRS) compared to high-level BRS (HL-BRS) on atrial arrhythmogenic changes in a pig model of OSA.
  
  
  
  Sixteen pigs received tracheotomy under general urethane/chloralose anesthesia. Group 1 pigs (n = 8) received LL-BRS (at 80% of that slowing sinus rate) for 3 hours and group 2 pigs (n = 8) received HL-BRS (slowing sinus rate). Changes in atrial effective refractory period (AERP) and AF-inducibility were determined during applied negative thoracic pressure (NTP) for 2 minutes before and at the end of the 3-hour stimulation protocol. Group 1: LL-BRS prolonged AERP from 150 ± 5 to 172 ± 19 milliseconds (P < 0.001). After 3 hours of LL-BRS, NTP-induced AERP-shortening was diminished from -51 ± 10 milliseconds (-34%) to -22 ± 4 milliseconds (-13%) (P < 0.01). AF-inducibility during NTP maneuvers decreased from 90% at baseline to 15% (P < 0.01). Group 2: HL-BRS shortened AERP from 150 ± 17 to 132 ± 8 milliseconds (P = 0.024). After 3 hours of HL-BRS, NTP-induced AERP-shortening was increased from -55 ± 7 milliseconds (-36%) to -72 ± 11 milliseconds (-54%) (P < 0.05) and AF-inducibility was not affected. NTP-induced changes in blood gases and blood pressure were not different between the groups.
  
  
  
  LL-BRS suppressed NTP-induced AERP-shortening and AF-inducibility. By contrast HL-BRS further perpetuated NTP-induced AERP-shortening and increased AF-inducibility. These findings support only the use of LL-BRS as a novel therapeutic modality to treat AF in OSA.
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany. Dominik.Linz@gmx.de.
authors.forename: Dominik
authors.initials: D
authors.lastname: Linz
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Hohl
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Shayan
authors.initials: S
authors.lastname: Khoshkish
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Mahfoud
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Ukena
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Hans-Ruprecht
authors.initials: HR
authors.lastname: Neuberger
authors.affiliation: Sanofi-Aventis Deutschland GmbH, R&D, Frankfurt, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Wirth
authors.affiliation: Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homburg, Saar, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Böhm
mesh_terms: D000200:Action Potentials; D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D016275:Atrial Function; D001794:Blood Pressure; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy / Q000379:methods*; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D008297:Male; D011311:Pressoreceptors / Q000503:physiopathology*; D012032:Refractory Period, Electrophysiological; D012119:Respiration; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D034421:Sus scrofa; D013997:Time Factors
keywords: atrial fibrillation; autonomic nervous system; baroreflex stimulation; obstructive sleep apnea; sympatho-vagal balance