title: Implantable cardioverter-defibrillators in tetralogy of Fallot.
abstract: BACKGROUND
  Tetralogy of Fallot is the most common form of congenital heart disease in implantable cardioverter-defibrillator (ICD) recipients, yet little is known about the value of ICDs in this patient population.
  
  
  RESULTS
  We conducted a multicenter cohort study in high-risk patients with Tetralogy of Fallot to determine actuarial rates of ICD discharges, identify risk factors, and characterize ICD-related complications. A total of 121 patients (median age 33.3 years; 59.5% male) were enrolled from 11 sites and followed up for a median of 3.7 years. ICDs were implanted for primary prevention in 68 patients (56.2%) and for secondary prevention in 53 (43.8%), defined by clinical sustained ventricular tachyarrhythmia or resuscitated sudden death. Overall, 37 patients (30.6%) received at least 1 appropriate and effective ICD discharge, with a median ventricular tachyarrhythmia rate of 213 bpm. Annual actuarial rates of appropriate ICD shocks were 7.7% and 9.8% in primary and secondary prevention, respectively (P=0.11). A higher left ventricular end-diastolic pressure (hazard ratio 1.3 per mm Hg, P=0.004) and nonsustained ventricular tachycardia (hazard ratio 3.7, P=0.023) independently predicted appropriate ICD shocks in primary prevention. Inappropriate shocks occurred in 5.8% of patients yearly. Additionally, 36 patients (29.8%) experienced complications, of which 6 (5.0%) were acute, 25 (20.7%) were late lead-related, and 7 (5.8%) were late generator-related complications. Nine patients died during follow-up, which corresponds to an actuarial annual mortality rate of 2.2%, which did not differ between the primary and secondary prevention groups.
  
  
  CONCLUSIONS
  Patients with tetralogy of Fallot and ICDs for primary and secondary prevention experience high rates of appropriate and effective shocks; however, inappropriate shocks and late lead-related complications are common.
authors.affiliation: Adult Congenital Heart Center, Montreal Heart Institute, 5000 Bélanger St, Montreal, Quebec, Canada H1T 1C8. paul.khairy@umontreal.ca
authors.forename: Paul
authors.initials: P
authors.lastname: Khairy
authors.forename: Louise
authors.initials: L
authors.lastname: Harris
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Landzberg
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Viswanathan
authors.forename: Amanda
authors.initials: A
authors.lastname: Barlow
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gatzoulis
authors.forename: Susan M
authors.initials: SM
authors.lastname: Fernandes
authors.forename: Luc
authors.initials: L
authors.lastname: Beauchesne
authors.forename: Judith
authors.initials: J
authors.lastname: Therrien
authors.forename: Philippe
authors.initials: P
authors.lastname: Chetaille
authors.forename: Elaine
authors.initials: E
authors.lastname: Gordon
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vonder Muhll
authors.forename: Frank
authors.initials: F
authors.lastname: Cecchin
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular; D013771:Tetralogy of Fallot / Q000628:therapy*