Randomized trials of implantable cardioverter defibrillators (ICDs) for primary prevention predominantly employed single chamber devices. In clinical practice, patients often receive dual chamber ICDs, even without clear indications for pacing. The outcomes of dual versus single chamber devices are uncertain.
Compare outcomes of single and dual chamber ICDs for primary prevention of sudden cardiac death.
Design, Setting, and Participants
Retrospective cohort study. Admissions in the National Cardiovascular Data Registry’s (NCDR®) ICD Registry™ from 2006–2009 that could be linked to CMS fee for service Medicare claims data were identified. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing.
Main Outcome Measures
Adjusted risks of 1-year mortality, all-cause readmission, HF readmission and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician and hospital factors.
Among 32,034 patients, 38% (n=12,246) received a single chamber device and 62% (n=19,788) received a dual chamber device. In a propensity-matched cohort, rates of complications were lower for single chamber devices (3.5% vs. 4.7%; p<0.001; risk difference −1.20; 95% CI −1.72, −0.69), but device type was not significantly associated with mortality or hospitalization outcomes (unadjusted rate 9.9% vs. 9.8%; HR 0.99, 95% CI 0.91–1.07; p=0.792 for 1-year mortality; unadjusted rate 43.9% vs. 44.8%; HR 1.00, 95% CI 0.97–1.04; p=0.821 for 1-year all-cause hospitalization; unadjusted rate 14.7% vs. 15.4%; HR 1.05, 95% CI 0.99–1.12; p=0.189 for 1-year HF hospitalization).
Conclusions and Relevance
Among patients receiving an ICD for primary prevention without indications for pacing, the use of a dual chamber device compared with a single chamber device was associated with a higher risk of device-related complications but not with different risks for mortality or hospitalization. Further studies should be performed to determine if other benefits of dual chamber devices exist, such as reduced device therapy or improved quality of life, to justify their use in this context.