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Effective Health Care Program

Analysis of Device Shock Patterns Among Patients With Implantable Cardiac Defibrillators (ICDs)

Abstract Archived

Topic Abstract

Background: ICDs have been shown to provide an overall mortality benefit in patients at high risk of sudden cardiac arrest. However, evidence from available trials has not fully established the utility of an ICD in clinically important patient subgroups. There is also growing evidence that ICD electrical shocks, particularly those that are inappropriate, may have significant harms. Furthur evidence is needed to improve patient selection for ICDs. This is a jointly funded study with the National Heart, Lung, and Blood Institute and the American College of Cardiology Foundation.

Objective: To study the patterns and appropriateness of ICD therapies among community practice patients following ICD implantation for primary prevention of sudden cardiac death.

Study design: Retrospective cohort study.

Methods: This study will combine data from a large, national ICD registry with electronic health records from several large health insurance plans to identify patients who have had an ICD implantation. These patients will then be followed for three years through the electronic records to determine if the ICD has delivered electrical shocks through firing. These firings will be analyzed by an expert clinical panel to determine if the firing was appropriate and the outcome of that firing. Approximately 3500 patients will be followed. The primary outcome will be the time to first appropriate device therapy. Secondary analyses will assess total number of appropriate and inappropriate therapies. Supplemental analyses using automated data will attempt to evaluate overall survival.

Expected Outputs: Three scientific reports.

Expected date of project completion: Phase 1 will be completed in September, 2011