Beta-blocker utilization and outcomes in patients receiving cardiac resynchronization therapy.

INTRODUCTION: Optimal pharmacologic therapy (OPT) is considered a prerequisite to consideration for cardiac resynchronization therapy (CRT).

HYPOTHESIS: Medications such as beta-blockers (BB) with demonstrated benefit in heart failure (HF) are being under utilized in patients receiving CRT.

METHODS: Consecutive patients receiving a CRT-capable defibrillator in 2004 at a tertiary care center for standard indications were studied. Clinical data and medications upon hospital discharge were recorded. Patients were followed for endpoints of death or transplantation.

RESULTS: Of 177 patients receiving a CRT device, 129 (73%) received BB therapy (group 1). Of the 48 patients not on BBs (group 2), relative contraindications were documented in 21 (allergy in 3, hypotension or inotrope-dependent HF in 4, chronic obstructive pulmonary disease [COPD] in 6, and amiodarone therapy in 8). The remaining 27 patients (group 3) did not receive BB therapy despite absence of documented justification. Compared to group 1, group 3 patients were similar in terms of clinical characteristics and angiotensin-converting enzyme inhibitor (ACEI) use, but were less likely to be on statin therapy. Patients were followed for a mean of 19.9 +/- 9.2 mo. After adjusting for age, QRS duration, creatinine, left ventricular ejection fraction (LVEF), statin use, and presence of ischemic HF etiology, patients not receiving BB therapy in the absence of contraindication had increased risk of death or transplantation (odds ratio [OR]: 3.1, p = 0.043).

CONCLUSIONS: Absence of BB therapy appears to be independently associated with poor outcome in CRT recipients. These results suggest that a crucial component of OPT may be underutilized in a population of HF patients receiving CRT.