title: Restoring Sinus Rhythm Improves Baroreflex Function in Patients With Persistent Atrial Fibrillation.
abstract: BACKGROUND
  Studies have suggested that patients with atrial fibrillation (AF) have impairment in the baroreflex. It is not clear whether these findings are the result of the associated comorbid conditions or the arrhythmia itself. We hypothesized that AF is associated with impairment in baroreflex function and that the arrhythmia itself is a contributing factor.
  
  
  RESULTS
  Twenty-four patients with persistent AF referred for cardioversion were enrolled. A second group of patients with no history of AF matched for age and left ventricular ejection fraction was identified and served as the control group. In the AF group, baroreflex gain (BRG) was measured on the day of cardioversion (Day 1) and again at 30 days post-cardioversion (Day 30) in patients who remained in sinus rhythm (SR). The clinical characteristics of patients with AF were not different than those of the control group. The mean BRG in the AF group on Day 1 was significantly lower than the mean BRG of the control group (5.2±3.6 versus 10.8±5.5 ms/mm Hg, P<0.05). Ten patients experienced AF recurrence before the 30-day follow-up and 14 patients remained in SR. In the group that remained in SR, BRG increased from 4.1±3.7 ms/mm Hg on Day 1 to 7.0±6.0 ms/mm Hg on Day 30 (P<0.01).
  
  
  CONCLUSIONS
  We have shown that AF is associated with impairment of the baroreflex and that restoration of SR improves BRG. Our data suggest that AF might be a contributing factor to the observed impairment in BRG and that restoring SR might help improve baroreflex function.
authors.affiliation: Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Field
authors.affiliation: Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Wasmund
authors.affiliation: Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Page
authors.affiliation: Division of Cardiovascular Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI mhamdan@medicine.wisc.edu.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Hamdan
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D017704:Baroreflex; D001794:Blood Pressure; D016022:Case-Control Studies; D004554:Electric Countershock; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D012008:Recurrence; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014589:Utah; D014922:Wisconsin
keywords: atrial fibrillation; baroreflex gain; hypertension