title: A prospective randomized trial of single- or dual-chamber implantable cardioverter-defibrillators to minimize inappropriate shock risk in primary sudden cardiac death prevention.
abstract: OBJECTIVE
  Dual-chamber implantable cardioverter-defibrillators (ICDs) may improve specificity and reduce the risk of inappropriate shocks, and enhance atrial arrhythmia (AT/AF) detection to permit stroke prevention compared with single-chamber ICDs, but at additional expense and risk.
  
  
  RESULTS
  Patients (n = 100) receiving primary prevention ICDs at two USA and two Israeli centres were randomized to dual-chamber or single-chamber devices between December 2008 and December 2010 and were followed for 1 year. Programming in both groups included: delayed detection to avoid therapy for non-sustained episodes; high detection cut-off rates to avoid treating slower, better tolerated arrhythmias; minimized right ventricular pacing; and routine use of supraventricular-ventricular tahcycardia discriminators and antitachycardia pacing. The primary outcome was the proportion of patients with inappropriate shocks. One patient in each group (2%) received inappropriate shocks (P = 1.00). Death occurred in two patients in the single-chamber arm, and in none of the patients in the dual-chamber arm (P = 0.15). New AT/AF was detected in 12 patients (24%) in the dual-chamber group, vs. no patients in the single-chamber group (P < 0.001). Among US participants, the mean cost of dual- vs. single-chamber ICD implantation was $16 579 vs. $14 249, respectively (P < 0.001); there was no difference in the quality of life (EQ-5D index difference 0.013, P = 0.769; EQ VAS difference 3.3, P = 0.49).
  
  
  CONCLUSIONS
  When optimal programming is utilized, inappropriate shocks are rare in primary prevention patients with both single- and dual-chamber ICDs. The routine use of dual-chamber ICDs increases the expense without reducing inappropriate shocks or improving the quality of life at 1 year.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00787800.
authors.affiliation: Division of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA pfriedman@mayo.edu.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: Division of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: David
authors.initials: D
authors.lastname: Bradley
authors.affiliation: Division of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Celeste
authors.initials: C
authors.lastname: Koestler
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Slusser
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hodge
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Kent
authors.initials: K
authors.lastname: Bailey
authors.affiliation: Division of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Kusumoto
authors.affiliation: Division of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Munger
authors.affiliation: Division of Biomedical Statistics and Informatics, Electrophysiology and Pacing, Carmel Medical Center, Haifa, Israel.
authors.forename: Arie
authors.initials: A
authors.lastname: Militanu
authors.affiliation: Division of Biomedical Statistics and Informatics, Electrophysiology and Pacing, Heart Institute, Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Glikson
mesh_terms: D000465:Algorithms; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention; D011446:Prospective Studies; D011788:Quality of Life; D012306:Risk; D016896:Treatment Outcome
keywords: Implantable defibrillator; Quality of life; Shock prevention; Single vs. dual chamber