Cardiac resynchronization therapy utilization for heart failure: findings from IMPROVE HF.

BACKGROUND Cardiac resynchronization therapy (CRT) has established efficacy for patients with systolic heart failure (HF). Treatment rates and factors associated with CRT utilization among eligible patients in outpatient cardiology practices have not been well studied. METHODS IMPROVE HF is a prospective cohort study designed to characterize current management of patients with chronic HF and left ventricular ejection fraction <or=35% in a registry of outpatient cardiology practices located throughout the United States. Baseline data were abstracted by trained chart review specialists from May 31, 2005, through June 22, 2007, for 15,381 patients attending 167 outpatient cardiology practices. Multivariable analyses of patient and practice characteristics identified predictors of CRT for eligible patients. RESULTS A total of 1,373 patients were eligible for CRT based on current guideline criteria, and 533 (38.8%) received a CRT device, with 84.1% of these treated with a CRT-defibrillator. Cardiac resynchronization therapy use varied widely among practices, with 11.1% at the 25th percentile and 53.4% at the 75th percentile. Patient age, insurance, longer QRS duration, and practice location were independently associated with higher CRT utilization rates among eligible patients, whereas sex, HF etiology, and other clinical and laboratory parameters were not. CONCLUSIONS Despite being evidence based and guideline recommended, CRT is underutilized in eligible patients with significant variations associated with age, insurance, QRS duration, and geographic location of practices. Practice-specific performance improvement initiatives may be needed to reduce variations in use of CRT for eligible patients.