ICD
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
1 Heart Diseases Department, San Filippo Neri Hospital, Via Martinotti 20, 00135 Rome, Italy; 2 Cardiology Department, Hospital General Universitario de Valencia, Valencia, Spain; 3 Cardiology Department, Hospital General Universitario Gregorio Maranon, Madrid, Spain; 4 Cardiology Department, Hospital Universitario 12 de Octubre, Madrid, Spain; 5 Cardiology Department, University Hospital of Mannheim, Mannheim, Germany; 6 Cardiology Department, Santa Cruz Hospital, Carnaxide, Portugal; 7 Cardiology Department, Padre A. Micone Hospital, Genova, Italy; 8 Scientific and Clinical Department, Medtronic Iberica, Barcelona, Spain; 9 Scientific and Clinical Department, Medtronic Italia, Rome, Italy
Aims: 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.
Methods and 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).
Conclusion: 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.
Key Words: Atrial fibrillation, Single-chamber defibrillator, Dual defibrillator, Hospitalizations, Inappropriate shocks
* Corresponding author. Tel: +39 06 33063934, Fax: +39 06 33062489, Email: renatopietroricci{at}tin.it
Manuscript submitted 6 December 2008. Accepted after revision 17 February 2009.