title: Method of pacing does not affect the recurrence of syncope in carotid sinus syndrome.
abstract: BACKGROUND
  Pacemaker therapy is effective in reducing recurrent syncope in patients with symptomatic carotid sinus hypersensitivity (CSH), yet the optimal pacing modality for this syndrome is not known. The objective of this study is to prospectively investigate the impact of three pacing methods (DDDR vs DDDR with sudden bradycardia response [SBR] vs VVI) on recurrent syncope and quality of life.
  
  
  METHODS
  Twenty-one patients with symptomatic CSH (syncope or near syncope) were randomized to VVI, DDDR, or DDDR with SBR on a double-blinded basis in a sequential crossover fashion with 6 months in each mode. The primary endpoints were recurrent events and quality of life (assessed by SF-36). The mean number of events and SF-36 scores were compared.
  
  
  RESULTS
  At baseline, over the preceding 6 months, there were a total of 29 syncopal events and 258 presyncopal events among 21 patients. Following pacing in any mode, the total number of these syncopal events reduced to two in two patients (P < 0.001) and 17 presyncopal events (P < 0.001) in 12 patients. The mean number of events was not significantly different between the three pacing methods. SF-36 scores revealed some minor benefits of DDDR pacing versus baseline in the categories, but no pacing method was found to be superior.
  
  
  CONCLUSIONS
  The study was unable to confirm the initial study hypothesis of a superiority of one pacing modality over another. Quality of life measures allude to potential benefit from DDDR pacing alone.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: McLeod
authors.forename: Jane M
authors.initials: JM
authors.lastname: Trusty
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Jenkins
authors.forename: Robert F
authors.initials: RF
authors.lastname: Rea
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.forename: Raul A
authors.initials: RA
authors.lastname: Espinosa
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: David L
authors.initials: DL
authors.lastname: Hayes
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
mesh_terms: D000368:Aged; D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D055502:Secondary Prevention; D012680:Sensitivity and Specificity; D013575:Syncope / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods*