Pacemaker Could Aid Some Cases of Heart Failure
Device might help hearts adjust to physical activity, researchers say
WEDNESDAY, Nov. 8, 2006 (HealthDay News) -- Cardiologist researchers are proposing a new way of managing a specific type of heart failure: implanting a pacemaker to regulate heart function.
In heart failure, the organ typically loses its ability to efficiently pump blood, as measured by a reduction of the heart's "ejection fraction" -- the amount of blood pumped with each contraction.
However, about half of the 550,000 Americans diagnosed with heart failure each year have normal or near-normal ejection fractions, according to a report in the Nov. 6 online edition of Circulation.
According to lead researcher Dr. David Kass, professor of medicine at the Johns Hopkins School of Medicine, the problem for these patients is that the heart cannot respond properly to even minor physical activity, such as getting dressed.
The condition is called non-systolic heart failure, a reference to the "systole" or contraction of the heart. Unfortunately for these patients, non-systolic heart failure is not adequately treated using conventional methods such as medicines like beta-blockers, Kass said.
"Beta-blockers slow the heart," he explained. "If you think this is a disease of relaxing and filling the heart, that does give more time for the heart to fill. But, ironically, in non-systolic heart failure, by slowing heart rate, you might help when persons are at rest but not when they get up and do things.
That's what gave Kass' team the idea that pacemakers might be in order. "Maybe we should use pacemakers to help people whose heart rates don't go faster by themselves when they should -- not all the time, just when they are exercising," he said.
The Circulation paper compared 17 persons with heart failure with normal ejection fractions to 19 without heart failure. When they pedaled on stationary bicycles, their hearts filled with blood in a normal way. But the hearts of those with non-systolic heart failure beat 44 percent less quickly, and their blood vessels did not expand to allow more blood to reach the muscles.
The Hopkins group is planning a trial to see if pacemakers could correct that problem. It will include about 100 people with non-systolic heart failure, split between those who do and do not take beta blockers.
"It will be designed to see if pacemakers help them feel better, exercise better and improve their symptoms," Kass said.
There have been very few trials on treatment of non-systolic heart failure, he said, because recruiters for such trials have always looked for people with low ejection fractions. "The other group of patients with normal ejection fraction is growing in size," Kass said. "They tend to be older, more often are women and commonly with high blood pressure."
Dr. Gerald Fletcher, a preventive cardiologist at the Mayo Clinic, called the new research a "fascinating" study. "It shows that heart failure is a generalized system problem, not just affecting the heart directly," he said.
As for using pacemakers for the condition, "that has to be judged patient-by-patient," Fletcher said.
"A pacemaker might be indicated in some cases, particularly if the patient has a problem with medications," he said.
There's more on heart failure at the American Heart Association.