Longitudinal Study of Implantable Cardioverter-Defibrillators: Methods and Clinical Characteristics of Patients Receiving Implantable Cardioverter-Defibrillators for Primary Prevention in Contemporary Practice

Study Questions:

What are the clinical characteristics and long-term outcomes of unselected, community-based patients with left ventricular systolic dysfunction undergoing primary prevention implantable cardioverter-defibrillator (ICD) implantation in a real-world setting?


The study cohort includes consecutive patients undergoing primary prevention ICD placement between January 1, 2006 and December 31, 2009, in seven health plans. Baseline clinical characteristics were acquired from the National Cardiovascular Data Registry (NCDR) ICD Registry. Longitudinal data collection is underway, and will include hospitalization, mortality, and resource use from standardized health plan data archives. Data regarding ICD therapies will be obtained through chart abstraction and adjudicated by a panel of experts in device therapy.


Compared with the populations of primary prevention ICD therapy randomized, controlled trials, the cohort (n = 2,621) is on average significantly older (by 2.5-6.5 years), more often female, more often from racial and ethnic minority groups, and has a higher burden of coexisting conditions. The cohort is similar, however, to a national population undergoing primary prevention ICD placement.


The authors concluded that patients undergoing primary prevention ICD implantation in this study differ from those enrolled in the randomized, controlled trials that established the efficacy of ICDs.


The current study is designed to assess a broad range of patient outcomes, including ICD therapies, in a contemporary community population of patients receiving an ICD for the primary prevention of sudden cardiac death. This study cohort differs substantially from participants enrolled in the randomized, controlled trials that form the basis of current guideline recommendations for primary prevention ICD implantation in that the cohort was older, had a higher proportion of women and nonwhite patients, and had a significantly higher burden of comorbid illnesses. Understanding a broad range of health outcomes, including ICD therapies in a diverse patient population, will provide patients, clinicians, and policy makers with contemporary data to inform decision making, including Centers for Medicare and Medicaid Services coverage questions related to ICD therapy.

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

Keywords: Heart Diseases, Ethnic Groups, Defibrillators, Ventricular Dysfunction, Death, Heart Failure, Centers for Medicare and Medicaid Services (U.S.), Primary Prevention, United States

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