title: The role of pacemaker in hypersensitive carotid sinus syndrome.
abstract: OBJECTIVE
  About 15% of patients with the hypersensitive carotid sinus syndrome (CSS) have no clinical improvement after permanent pacemaker implantation. We aimed to assess the outcome of patients with CSS treated with pacemaker and to determine predictors of symptoms' recurrence.
  
  
  RESULTS
  A retrospective analysis of 138 patients in whom pacemaker was implanted for CSS was carried out from February 1990 to October 2008. Data were collected from clinical records. Mean age was 69 ± 10.7 years and 104 patients (75.4%) were men. Mean follow-up period was 4.9 ± 4.4 years. Twenty-one (15.2%) patients presented mixed CSS and 117 (84.8%) cardioinhibitory CSS. The head-up tilt test (HUTT) was performed in 93 patients (67.4%). After pacemaker implantation, 115 (83.3%) patients had no further symptoms, 8 (5.8%) presented minor symptoms and in 15 (10.9%), the symptoms remained unchanged. Among patients with symptoms' recurrence, 8 (38.1%) had mixed CSS and 15 (12.8%) cardioinhibitory CSS. Mixed CSS was the only independent predictor of symptoms' recurrence in total population {hazard ratio (HR) 2.84 [95% confidence intervals (CI) 1.20-6.71]; P = 0.017} and in patients who performed HUTT [HR 1.84 (95% CI 1.01-3.35); P = 0.045]. Although the HUTT result was not related to symptoms' recurrence, patients with mixed CSS were more likely to present a vasodepressor response (61.9 vs. 19.4%; P < 0.001) and a reproduction of spontaneous symptoms (28.6 vs. 2.8%; P = 0,001) on HUTT.
  
  
  CONCLUSIONS
  Permanent pacemaker is an effective treatment for CSS. However, the recurrence of symptoms was two- to three-fold more frequent in patients with mixed CSS, probably due to the persistence of vasodepressor component.
authors.affiliation: Department of Cardiology, Hospital de São João, E.P.E, Serviço de Cardiologia, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal. rjlclopes@hotmail.com
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lopes
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gonçalves
authors.forename: Júlio
authors.initials: J
authors.lastname: Campos
authors.forename: Cecília
authors.initials: C
authors.lastname: Frutuoso
authors.forename: Anabela
authors.initials: A
authors.lastname: Silva
authors.forename: Cristina
authors.initials: C
authors.lastname: Touguinha
authors.forename: João
authors.initials: J
authors.lastname: Freitas
authors.forename: Maria Júlia
authors.initials: MJ
authors.lastname: Maciel
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012008:Recurrence; D012044:Regression Analysis; D012189:Retrospective Studies; D013575:Syncope / Q000503:physiopathology / Q000628:therapy*; D019462:Syncope, Vasovagal / Q000503:physiopathology; D016896:Treatment Outcome