title: Syncope and risk of sudden death in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  The prognostic significance of syncope has not been investigated systematically in hypertrophic cardiomyopathy, and treatment strategies have been based largely on intuition and experience.
  
  
  RESULTS
  We assessed the relationship between syncope and sudden death in 1511 consecutive patients with hypertrophic cardiomyopathy. Unexplained (n=153) or neurally mediated (n=52) syncope occurred in 205 patients (14%). Over a 5.6+/-5.2-year follow-up, 74 patients died suddenly. Relative risk of sudden death was 1.78 (95% confidence interval 0.88 to 3.51, P=0.08) in patients with unexplained syncope and 0.91 (95% confidence interval 0.00 to 3.83, P=1.0) in those with neurally mediated syncope compared with patients without syncope. In multivariable analysis, the temporal proximity of unexplained syncope to initial patient evaluation was independently associated with risk of sudden death (P=0.006). Patients with unexplained syncope within 6 months before the initial evaluation showed a 5-fold increase in risk compared with patients without syncope (adjusted hazard ratio 4.89, 95% confidence interval 2.19 to 10.94), a relationship that was maintained throughout all age groups (<18, 18 to 39, and > or =40 years). Older patients (> or =40 years of age) with remote episodes of syncope (>5 years before initial evaluation) did not show an increased risk of sudden death (adjusted hazard ratio 0.38, 95% confidence interval 0.05 to 2.74).
  
  
  CONCLUSIONS
  In the present large cohort of patients with hypertrophic cardiomyopathy, unexplained syncope was a risk factor for sudden death. Patients with syncopal events that occurred in close temporal proximity to the initial evaluation showed a substantially higher risk of sudden death than patients without syncope. Older patients with remote syncopal events did not show an increased risk.
authors.affiliation: Divisione di Cardiologia, Ente Ospedaliero Ospedali Galliera, Via Volta 8, Genova 16128, Italy. paolo.spirito@galliera.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Spirito
authors.forename: Camillo
authors.initials: C
authors.lastname: Autore
authors.forename: Claudio
authors.initials: C
authors.lastname: Rapezzi
authors.forename: Paola
authors.initials: P
authors.lastname: Bernabò
authors.forename: Roberto
authors.initials: R
authors.lastname: Badagliacca
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.forename: Sergio
authors.initials: S
authors.lastname: Bongioanni
authors.forename: Fabio
authors.initials: F
authors.lastname: Coccolo
authors.forename: N A Mark
authors.initials: NA
authors.lastname: Estes
authors.forename: Caterina S
authors.initials: CS
authors.lastname: Barillà
authors.forename: Elena
authors.initials: E
authors.lastname: Biagini
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarta
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Conte
authors.forename: Paolo
authors.initials: P
authors.lastname: Bruzzi
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000401:mortality* / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D013575:Syncope / Q000401:mortality* / Q000628:therapy; D055815:Young Adult