Introduction:
Dual chamber ICD implantation has been associated with higher complication rates than single chamber ICD implantation without associated decrease in morbidity or mortality in prior reports. If this association is present using validated long term outcomes or whether the same is true for cardiac resynchronization therapy defibrillator (CRT-D) devices is not well described.
Methods:
The OVID registry enrolled 3,918 veterans between 2003 and 2009. Retrospective chart abstraction from enrollment to implant date captured pre- and peri-procedural data. Patients were then followed prospectively until death or study conclusion. Abstraction was done by trained abstractors. Clinical outcomes and mortality were abstracted and validated. Mortality was cross referenced with the social security death index. Association of ICD type (single chamber, dual chamber, CRT-D) with mortality, non-fatal major events (major adverse cardiac events, TIA, stroke, cardiogenic syncope, cardiac hospitalization, device complication or infection, procedural complications), and the composite of mortality and non-fatal events was examined using Cox proportional hazards regression, adjusting for baseline clinical characteristics and comorbidities.
Results:
There were 786 deaths and 1143 non-fatal major events over 11,290 person years of follow up. In unadjusted analyses, CRT-D was associated with non-fatal major events (HR 1.26, 95% CI 1.09-1.45; p<0.05) and the composite outcome (HR 1.12, 95% CI 1.06-1.35; p<0.05) as was Dual chamber ICD (non-fatal major-HR 1.19, 95% CI 1.03-1.37; p<0.05, composite-HR 1.17, 95% CI 1.04-1.31; p<0.05). No significant difference existed in risk between ICD types in the unadjusted analysis of mortality or for any outcome when adjusted for clinical covariates.
Conclusions:
Unadjusted analyses showed an association between dual chamber ICD and CRT-D devices and risk of non-fatal major events and the composite outcome versus single chamber ICD implantation. This did not persist when adjusted for clinical characteristics and comorbidities, though we are underpowered for small differences. Further study is needed as prior reports may not have adjusted adequately for clinical covariates and lacked validated outcomes.
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
