Regional Variation in the Use of Implantable Cardioverter-Defibrillators for Primary Prevention: Results From the National Cardiovascular Data Registry

Study Questions:

Is there geographic variability in the use of implantable cardioverter-defibrillators (ICDs)?


The data in this study were obtained from the NCDR’s ICD RegistryTM of 64,220 Medicare patients (mean age 76 years) who received an ICD for primary prevention of sudden cardiac death (SCD). Medicare and American Medical Association databases were used to estimate the number of Medicare beneficiaries, cardiologists, and electrophysiologists by geographic region.


The regional ICD implant rate ranged from 75 to 338 per 100,000 Medicare beneficiaries. There was no relationship between the regional implant rate and the supply of cardiologists or electrophysiologists. Clinical trial criteria for primary prevention of SCD were not met in 13% of ICD recipients, with a regional range of 4-52%. There was no association between the regional implant rate and the proportion of patients not meeting standard implant criteria.


There is marked geographic variability in the implant rate of ICDs for primary prevention of SCD and in the proportion of ICD recipients who do not meet standard implant criteria.


Regional differences in health might explain the variation in ICD implant rate, but this is unlikely because some high-utilization regions were immediately adjacent to low-utilization regions. Whether a region was mostly urban or rural also did not explain the regional variation. Regional differences based on age, gender, or racial differences were ruled out by adjusting the implant rates for these variables. Local practice patterns may be a major factor driving the regional differences in implant rates. Of note is that whether the marked variation is due to regional overutilization or underutilization (or both) is unclear.

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Clinical Topics: Arrhythmias and Clinical EP, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias

Keywords: Registries, Electrophysiological Phenomena, Medicare, Death, Sudden, Cardiac, Defibrillators, Implantable, Primary Prevention, United States

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