Most patients with heart failure likely to benefit from a pacemaker with the capacity for cardiac resynchronization therapy (CRT) do not receive such an implantable device, according to a study in the December issue of the American Heart Journal.
Less than half who qualify for the device therapy may actually get it, based on a study led by Anne Curtis, MD, from University of South Florida (USF) in Tampa, Fla.
The researchers also reported widespread variations in CRT use for eligible patients by practice setting and patient characteristics despite national guidelines and evidence from clinical trials supporting the therapy.
Heart failure affects more than five million Americans and is expected to increase as the population ages. Some patients with severe heart failure have hearts that are not only weak and inefficient, but also beat in a disorganized, or unsynchronized, way. Studies have shown that these patients, who are at high risk for sudden death, benefit greatly from CRT to help their hearts beat with proper timing.
"Our study shows great variability among doctors and practices with respect to how many eligible patients actually receive cardiac resynchronization therapy for heart failure," said Curtis, professor and chair of cardiology at USF Health.
"Since resynchronization therapy can help patients with heart failure feel better and improve outcomes, it is important to continue our efforts to get this information out and improve access to effective medical treatments," the authors wrote.
The study drew on more than 15,000 heart failure patients from 167 U.S. cardiology practices enrolled in the Registry to Improve the Use of Evidence-Based Heart Failure Therapies in the Outpatient Setting (IMPROVE HF).
Only 38.8 percent of the 1,373 patients in the registry who fit the criteria for receiving CRT were implanted with a CRT-capable device, the authors reported. Four-fifths of this group received a pacemaker combining resynchronization therapy with a defibrillator (CRT-D) to shock the heart if it stopped suddenly, and the rest got a pacing-only device (CRT-P).
"Notably, ICD [implantable cardiac defibrillator] implantation rates were higher [50 percent] for patients eligible for CRT but not treated for CRT," the authors wrote, "which is not well aligned to evidence showing greater magnitude of benefit from CRT."
Use of CRT among the 167 cardiology practices in IMROVE HF ranged from none to 100 percent of eligible patients.
Of the 533 patients who received a CRT device, 84.1 percent were treated with a CRT-D. Overall, CRT use varied widely among practices, with 11.1 percent at the 25th percentile and 53.4 percent at the 75th percentile, Curtis and colleagues reported. They also found that patient age, insurance, longer QRS duration, and practice location were independently associated with higher CRT utilization rates among eligible patients, whereas sex, heart failure etiology and other clinical and laboratory parameters were not.
"Practice-specific performance improvement initiatives may be needed to reduce variations in use of CRT for eligible patients," the authors concluded.
The IMPROVE HF registry and study is sponsored by Medtronic, and the authors served as consultants to Medtronic.