Variation in Use of Dual-Chamber Implantable Cardioverter-Defibrillators: Results From the National Cardiovascular Data Registry

Study Questions:

What proportion of implantable cardioverter-defibrillators (ICDs) used in the United States are dual-chamber?


The data for this study were obtained from a national ICD registry. All patients who received an ICD in 2006-2009 for primary prevention of sudden cardiac death were included. The data were analyzed by geographic region.


A total of 87,115 patients (mean age 63 years) received a first-time ICD. The ICD was dual-chamber in 58% of patients and single-chamber in 42%. Between 2006 and 2009, the proportion of ICDs that were dual-chamber increased from 53% to 62%. The hospital- and physician-rate of dual-chamber ICD implantation ranged from 0 to 100%.The proportion of ICDs that were dual-chamber was lowest in the New England region (36.4%) and highest in the Pacific region (66.4%). Independent predictors of a dual-chamber ICD were older age, atrial fibrillation, hypertension, and implantation by a surgeon. Independent predictors of a single-chamber ICD were black ethnicity, hemodialysis, and ICD implantation at an academic medical center.


The authors concluded that there is marked variability in the use of dual-chamber ICDs between physicians and geographical regions in the United States.


This study convincingly demonstrates that the decision to implant a dual- versus single-chamber ICD in patients who do not have an indication for pacing is driven in large part by personal preference and regional practice patterns. The evidence favoring dual-chamber ICDs is inconclusive. For example, while an atrial lead allows detection of atrial arrhythmias, no studies have convincingly demonstrated a lower incidence of inappropriate shocks in patients with dual-chamber ICDs compared to single-chamber ICDs. Furthermore, the operative complication rate is higher with dual-chamber ICDs.

Clinical Topics: Arrhythmias and Clinical EP, Prevention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Hypertension

Keywords: Defibrillators, Electric Countershock, Primary Prevention, New England, Tachycardia, Renal Dialysis, Registries, Death, United States, Hypertension

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