Study finds widespread variations in CRT use for patients with severe heart failure

Most patients with heart failure likely to benefit from a pacemaker including the capacity for cardiac resynchronization therapy (CRT) do not receive such an implantable device, reports a national study in the December 2009 issue of the American Heart Journal. Less than half who qualify for the device therapy may actually get it, the large-scale study led by University of South Florida cardiologist Anne Curtis, MD, found.

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 - impairment in the heart's ability to pump blood through the body - affects more than 5 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 lead author Dr. 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 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 for none to 100 percent of eligible patients. A few factors emerged as significant predictors in the analysis: sex, cause of heart failure, other complicating illnesses, and clinical and laboratory markers were not among them. Among patients treated with CRT, older patient age, female sex, device-clinic affiliated practices and single specialty were associated with the use of CRT-P rather than CRT-D.