(Reuters Health) - Blacks and Hispanics with chronic heart failure are less likely than whites to be treated with a specialized pacemaker that prolongs survival and eases symptoms, U.S. researchers said Tuesday.

And while more and more patients are getting the treatment, called cardiac resynchronization therapy, the racial gap has remained, said Dr. Zubin Eapen of Duke University School of Medicine in Durham, North Carolina.

"New technologies tend to diffuse unevenly across racial and ethnic lines," he told Reuters Health. "This is an example of underutilization of a recommended therapy in eligible patients."

The new study, published by Eapen and his colleagues in the Journal of the American College of Cardiology, is the latest to point to healthcare disparities in the U.S.

More than five million Americans have chronic heart failure, which can cause pronounced fatigue and shortness of breath. In some people with this condition the two big chambers of the heart fail to contract in sync, further reducing the heart's ability to pump out blood.

In cardiac resynchronization therapy with defibrillation, or CRT-D, a pacemaker-like device helps the two chambers pump properly. The units sell for tens of thousands of dollars.

The researchers identified more than 100,000 patients eligible for CRT-D from a U.S. registry of heart devices known as implantable cardioverter-defibrillators.

Between 2006 and 2010, the percentage of white patients receiving the therapy climbed from 81 percent to 84 percent.

For blacks, the number went from 78 percent to 81 percent and for Hispanics, from 77 percent to 79 percent.

"Despite all the initiatives that we have had," said Eapen, "we are still having the unequal diffusion across racial lines."

The racial gap remained after accounting for a number of possible explanations, such as differences in age, gender, hospital region and other diseases between the groups. And they held up when looking only at Medicare beneficiaries, for whom cost should not be a factor.

The reasons behind the disparity are unclear, but personal preferences, provider biases and access to care could all be at work, according to Eapen.

As the electronic health record becomes more widespread, guiding doctors toward the appropriate treatment for their patients, the gap is likely to narrow, he added.

SOURCE: bit.ly/d1cHYE Journal of the American College of Cardiology, online September 5, 2012.