Use of cardiac resynchronization therapy in patients hospitalized with heart failure

The frequency and characterization of patients receiving cardiac resynchronization therapy (CRT) are largely unknown since the publication of pivotal clinical trials and subsequent incorporation of CRT into the American College of Cardiology/American Heart Association guidelines for heart failure.

We analyzed 33,898 patients admitted from January 2005 through September 2007 to 228 hospitals participating in the American Heart Association's Get With the Guidelines-Heart Failure program. There were 4201 patients (12.4%) discharged alive with CRT, including 811 new implants. Patients discharged with CRT were older (median age, 75 versus 72 years) and had lower median left ventricular ejection fraction (30% versus 38%), more frequent ischemic cardiomyopathy (58% versus 45%), more history of atrial fibrillation (38% versus 27%), and higher rates of beta-blocker and aldosterone antagonist use (P<0.0001 for all) than those without CRT. We found that 4.8% of patients with left ventricular ejection fraction 35%. Major factors associated with lower rates of new CRT placement were treatment in the northeast (odds ratio, 0.40; 95% confidence interval, 0.30 to 0.53), black race (odds ratio, 0.45; 95% confidence interval, 0.36 to 0.57), increasing left ventricular ejection fraction per 10% (odds ratio, 0.56; 95% confidence interval, 0.52 to 0.60), and increasing age per 10 years in those >70 years of age (odds ratio, 0.56; 95% confidence interval, 0.48 to 0.65).

Although CRT is a recent evidence-based therapy for heart failure, patterns of use differ significantly from clinical trials and published guidelines. Important variations also exist for CRT therapy based on race, geographic region, comorbidities, and age and need to be addressed through further study and/or quality-of-care initiatives.