title: The long-term survival and the risks and benefits of implantable cardioverter defibrillators in patients with hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  Implantable cardioverter defibrillators (ICDs) are routinely used to prevent sudden cardiac death (SCD) in selected hypertrophic cardiomyopathy (HCM) patients, but the determinants of device-related complications, therapies and long-term cardiovascular mortality in ICD recipients are not known.
  
  
  METHODS
  Retrospective observational cohort study.
  
  
  METHODS
  Single-centre tertiary referral cardiomyopathy clinic. Patients 334 consecutively evaluated HCM patients (median age 40 years, 62% male, 92% primary prevention) at risk of SCD treated with ICD. Thirty-six patients (11%) received concurrent cardiac resynchronisation therapy for heart failure symptoms.
  
  
  RESULTS
  During the 1286 patient-years of follow-up, cardiovascular mortality (including transplantation) occurred in 22 (7%) patients (1.7%/year) and was associated with New York Heart Association (NYHA) class III/IV (adjusted HR=9.38, 95% CI 3.31 to 26.55, p≤0.001), percentage fractional shortening (HR=0.92, 95% CI 0.87 to 0.96, p=0.001) and implantation for secondary prevention (HR=0.07, 95% CI 0.01 to 0.86, p=0.04). There were no SCD. Twenty-eight (8%) patients received appropriate shocks (2.3%/year), which were predicted by baseline fractional shortening (HR=0.96, 95% CI 0.92 to 0.99, p=0.04). Fifty-five (16%) patients received inappropriate shocks (4.6%/year). Sixty (18%) patients experienced implant-related complications (5.1%/year), including two deaths. Adverse ICD-related events (inappropriate shocks and/or implant complications) were seen in 101 (30%) patients (8.6%/year). Patients with cardiac resynchronisation therapy were more likely to develop implant complications than those with single-chamber ICDs (HR=4.39, 95% CI 1.44 to 13.35, p=0.009) and had a higher 5-year cardiovascular mortality than did the rest of the cohort (21% vs 6%, p<0.001).
  
  
  CONCLUSIONS
  HCM patients with an ICD have a significant cardiovascular mortality and are exposed to frequent inappropriate shocks and implant complications. These data suggest that new strategies are required to improve patient selection for ICDs and to prevent disease progression in those that receive a device.
authors.affiliation: The Heart Hospital, 16-18 Westmoreland Street, London, UK. perry.elliott@ucl.ac.uk
authors.forename: Constantinos
authors.initials: C
authors.lastname: O'Mahony
authors.forename: Pier D
authors.initials: PD
authors.lastname: Lambiase
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarta
authors.forename: Montserrat
authors.initials: M
authors.lastname: Cardona
authors.forename: Margherita
authors.initials: M
authors.lastname: Calcagnino
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Tsovolas
authors.forename: Shereen
authors.initials: S
authors.lastname: Al-Shaikh
authors.forename: Shafiqur M
authors.initials: SM
authors.lastname: Rahman
authors.forename: Samer
authors.initials: S
authors.lastname: Arnous
authors.forename: Sue
authors.initials: S
authors.lastname: Jones
authors.forename: William
authors.initials: W
authors.lastname: McKenna
authors.forename: Perry
authors.initials: P
authors.lastname: Elliott
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000401:mortality* / Q000628:therapy*; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome