title: Dual-chamber defibrillators reduce clinically significant adverse events compared with single-chamber devices: results from the DATAS (Dual chamber and Atrial Tachyarrhythmias Adverse events Study) trial.
abstract: OBJECTIVE
  This randomized trial evaluated clinically significant adverse events (CSAEs), in patients implanted with dual-chamber (DC) vs. single-chamber (SC) implantable cardioverter defibrillator (ICD). DC-ICD had atrial tachyarrhythmia (AT) therapy capabilities. Strict programming recommendations were reinforced.
  
  
  RESULTS
  Patients with conventional SC-ICD indication were randomized to DC-ICD, SC-ICD, or a DC-ICD programmed as an SC-ICD (SC-simulated) and followed for 16 months. Patients in the DC and SC-simulated groups crossed over after 8 months. The primary endpoint was a composite of CSAE: all-cause mortality; invasive intervention; hospitalization (> 24 h) for cardiovascular causes; inappropriate shocks (two or more episodes); and sustained symptomatic AT lasting > 48 h. The outcome variable was a pre-specified score that corrected for clinical severity and follow-up duration. Three hundred and thirty-four patients were analysed (DC-ICD, n = 112; SC-ICD, n = 111; SC-simulated, n = 111). The mean left ventricular ejection fraction was 0.36 +/- 0.13, 69% were in functional class > or = II. CSAE occurred in 65 DC-ICD, 82 SC-ICD, and 84 SC-simulated patients. The outcome variable was 33% lower in the DC-ICD group (OR 0.31; 95% CI 0.14-0.67; P = 0.0028). Mortality was 4% in DC, 9% in SC, and 10% in SC-simulated.
  
  
  CONCLUSIONS
  In patients with a standard SC-ICD indication, DC-ICD was associated with less CSAE when compared with SC-ICD.
authors.affiliation: Cardiology Department, Hospital General Universitario Gregorio Maranon, Madrid, Spain. almendral@secardiologia.es
authors.forename: Jesus
authors.initials: J
authors.lastname: Almendral
authors.forename: Fernando
authors.initials: F
authors.lastname: Arribas
authors.forename: Christian
authors.initials: C
authors.lastname: Wolpert
authors.forename: Renato
authors.initials: R
authors.lastname: Ricci
authors.forename: Pedro
authors.initials: P
authors.lastname: Adragao
authors.forename: Erik
authors.initials: E
authors.lastname: Cobo
authors.forename: Xavier
authors.initials: X
authors.lastname: Navarro
authors.forename: Aurelio
authors.initials: A
authors.lastname: Quesada
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000401:mortality* / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005060:Europe; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate