Association of single- vs dual-chamber ICDs with mortality, readmissions, and complications among patients receiving an ICD for primary prevention

Abstract

Importance: Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain.

Objective: To compare outcomes of single- and dual-chamber ICDs for primary prevention of sudden cardiac death.

Design, setting, and participants: 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 & 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.

Main outcomes and measures: Adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician, and hospital factors.

Results: 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 < .001; risk difference, -1.20 [95% 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 to 1.07]; P = .79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs 44.83%; HR, 1.00 [95% CI, 0.97-1.04]; P = .82), or hospitalization for heart failure (unadjusted rate, 14.73% vs 15.38%; HR, 1.05 [95% CI, 0.99-1.12]; P = .19).

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 and similar 1-year mortality and hospitalization outcomes. Reasons for preferentially using dual-chamber ICDs in this setting remains unclear.

Figure 1

Study population.

Figure 2

Distribution of propensity scores for receipt of dual chamber device among single and dual chamber groups. The bin interval used was 0.05 with a range from 0.10–0.95. Bin limits were >0 to ≤0.10; >0.10 to ≤0.15, etc.