Association of Single- vs Dual-Chamber ICDs With Mortality, Readmissions, and Complications Among Patients Receiving an ICD for Primary Prevention

Study Questions:

What are the outcomes of single- and dual-chamber implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden cardiac death?


This was a retrospective cohort study of admissions in the National Cardiovascular Data Registry’s (NCDR) ICD registry from 2006-2009 that could be linked to Centers for Medicare and Medicaid Services fee-for-service Medicare claims data. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing. The main outcomes measures were adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days, which were estimated with propensity-score matching based on patient, clinician, and hospital factors.


Among 32,034 patients, 12,246 (38%) received a single-chamber device and 19,788 (62%) received a dual-chamber device. In a propensity-matched cohort, rates of complications were lower for single-chamber devices (3.51% vs. 4.72%; p < 0.001; risk difference, -1.20; 95% confidence interval [CI], -1.72 to -0.69), but device type was not significantly associated with 1-year mortality (unadjusted rate, 9.85% vs. 9.77%; hazard ratio [HR], 0.99; 95% CI, 0.91-1.07; p = 0.79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs. 44.83%; HR, 1.00; 95% CI, 0.97-1.04; p = 0.82), or hospitalization for heart failure (unadjusted rate, 14.73% vs. 15.38%; HR, 1.05; 95% CI, 0.99-1.12; p = 0.19).


The authors concluded that 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 and similar 1-year mortality and hospitalization outcomes.


This study reported no significant difference in mortality, all-cause hospitalization, or heart failure hospitalization between single- and dual-chamber device types at 1 year among patients who received single- or dual-chamber ICDs for primary prevention of sudden cardiac death. However, dual-chamber ICDs were associated with higher rates of complications. Therefore, among patients without clear pacing indications, the decision to implant a dual-chamber ICD for primary prevention should be considered carefully since reasons for preferentially using dual-chamber ICDs in this setting remain unclear, with no proven benefit and increased rate of complications.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Propensity Score, Heart Failure, Centers for Medicare and Medicaid Services (U.S.), Medicare, Hospitalization, Death, Sudden, Cardiac, Defibrillators, Implantable, Primary Prevention

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