title: Dual-chamber implantable cardioverter defibrillators reduce clinical adverse events related to atrial fibrillation when compared with single-chamber defibrillators: a subanalysis of the DATAS trial.
abstract: OBJECTIVE
  The aim of the present analysis of the DATAS study was to compare the impact of dual- vs. single-chamber defibrillators on atrial fibrillation (AF) occurrence and AF-related clinical events in patients with Class I indication for implantable cardioverter defibrillators (ICDs) and no indication for dual-chamber pacing.
  
  
  RESULTS
  Three hundred and thirty-four patients were randomized, through a centralized assignment, to single-chamber ICDs, dual-chamber ICDs programmed as single-chamber ICDs, and dual ICDs with full diagnostics and AF prevention and therapy capabilities. The latter two groups in the first 8 months of the study, when the study design was that of a randomized parallel trial, were compared in the present analysis. The primary endpoint was composed by the following AF-related clinical events: permanent AF, AF-related hospitalizations, cardiac-embolic events, and inappropriate ICD shocks due to AF misclassification. Two hundred and twenty-three patients were available for this analysis, of whom 111 in the single-chamber-simulated group and 112 in the dual-chamber true group. Atrial fibrillation-related composite endpoint raw incidence was 9 of 111 (8.1%) in the single-chamber group vs. 1 of 112 (0.9%) in the dual-chamber group (P = 0.0098 by Fisher's exact test). Single-chamber ICDs were associated with a significantly higher risk to develop the AF-related composite endpoint by Cox regression analysis (hazard ratio 8.25, 95% CI 1.03-65.96, P = 0.047) and by the Kaplan-Meier survival analysis (log-rank test, P = 0.047).
  
  
  CONCLUSIONS
  Dual-chamber ICDs compared with single-chamber ICDs reduced the incidence of an endpoint composed by permanent AF, AF-related hospitalizations, and ICD shocks deemed inappropriate due to AF misclassification.
authors.affiliation: Heart Diseases Department, San Filippo Neri Hospital, Via Martinotti 20, 00135 Rome, Italy. renatopietroricci@tin.it
authors.forename: Renato Pietro
authors.initials: RP
authors.lastname: Ricci
authors.forename: Aurelio
authors.initials: A
authors.lastname: Quesada
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: Pedro
authors.initials: P
authors.lastname: Adragao
authors.forename: Massimo
authors.initials: M
authors.lastname: Zoni-Berisso
authors.forename: Xavier
authors.initials: X
authors.lastname: Navarro
authors.forename: Tiziana
authors.initials: T
authors.lastname: DeSanto
authors.forename: Andrea
authors.initials: A
authors.lastname: Grammatico
authors.forename: Massimo
authors.initials: M
authors.lastname: Santini
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications* / Q000628:therapy*; D018592:Cross-Over Studies; D017147:Defibrillators, Implantable / Q000009:adverse effects; D004617:Embolism / Q000453:epidemiology; D023381:Endpoint Determination; D004867:Equipment Design; D006760:Hospitalization; D006801:Humans; D053208:Kaplan-Meier Estimate; D012044:Regression Analysis; D012307:Risk Factors