Use of -Blockers in Patients with an Implantable Cardioverter Defibrillator^{(July/August)}

¹ Associate Professor, School of Medicine, Duke University, Duke Clinical Research Institute, Durham, NC
² Senior Analyst Programmer, Duke Clinical Research Institute-Outcomes
³ Biostatistician, INC Research, Raleigh, NC
⁴ Assistant Professor, School of Medicine, Duke University, Duke Clinical Research Institute
⁵ Assistant Professor, Department of Biostatistics and Bioinformatics, Duke University, Duke Clinical Research Institute

^* To whom correspondence should be addressed. E-mail: allen003{at}mc.duke.edu.

	Abstract

BACKGROUND: Implantable cardioverter defibrillators (ICDs) are indicated for both primary and secondary prevention of sudden cardiac arrest. -Blockers are also indicated in most patients who have an indication for an ICD; however, their use in this population is not well described. Some clinicians may be unaware of the recommendation for -Blockers in this population.

OBJECTIVE: To explore -blocker use among ICD recipients.

METHODS: Adults who received their first ICD at Duke Hospital between July 1999 and July 2004 for primary or secondary prevention of sudden cardiac arrest were identified. Using hospital data, -blocker use was determined at time of discharge, and characteristics of users were compared with those of nonusers. Continued use of -blockers after ICD implant was explored in the subset of patients included in the Duke Databank for Cardiovascular Disease (DDCD).

RESULTS: The study cohort comprised 804 patients, 652 (81%) with ICD for secondary prevention of sudden cardiac arrest and 152 (19%) for primary prevention. The median age was 65 years and 75% of the patients were men. A total of 544 (68%) received a -blocker at time of ICD implant. There were no substantial changes in the proportion of patients with -blocker use from 1999 through 2004, overall or within the primary or secondary prevention groups. However, -blocker use was higher in the secondary prevention group than in the primary prevention group (69% vs 60%; p = 0.02). A higher proportion of -blocker users versus nonusers had ischemic heart disease (82% vs 68%; p < 0.0001), heart failure (84% vs 71%; p < 0.0001), previous myocardial infraction (51% vs 44%; p = 0.05), and ventricular arrhythmias (82% vs 76%; p = 0.04). Of the 425 patients included in the DDCD, only 241 (57%) were receiving -blockers at time of implant and during clinical follow-up.

CONCLUSIONS: Lower than optimal use of -blockers suggests the need for new methods of including evidence-based medications in clinical practice, especially for complex patients for whom numerous clinical practice guidelines may apply.

Key Words: -blocker, implantable cardioverter defibrillator, sudden cardiac arrest.

Reprints:Dr. Allen LaPointe, School of Medicine, Duke University, Duke Clinical Research Institute, North Pavilion, 2400 Pratt St., Durham, NC 27705, fax 919/668-7166, allen003@mc.duke.edu