Pacemakers may be better than beta blockers for some heart failure
12 November 2006
Baltimore, USA. Patients suffering from certain types of heart failure
may benefit more from pacemakers than from long-term use of medication,
according to new research from Johns Hopkins University in the USA.
Cardiologists at the University say patients with non-systolic heart
failure may benefit more from pacemakers to speed up the heartbeat rather
than from continual, long-term use of beta blockers, drugs that slow down
It is estimated that almost half of the 550,000 Americans newly diagnosed
each year with heart failure have the non-systolic form.
“Cardiologists are constantly being forced to rethink heart failure
because one size does not fit all,” says senior study investigator David
Kass, M.D., a professor at The Johns Hopkins University School of Medicine
and its Heart Institute. “We really have to be careful about how we diagnose
and approach its treatment.
“We also need to understand all facets and manifestations of the disease
because we are seeing ever-increasing numbers of older adults who have heart
failure, mostly women over age 50, whose heart pumping appears to be normal.
And their cases are clearly different from traditional, systolic heart
failure, where pumping function is depressed. However, almost all of the
research over the last three decades has applied only to those with systolic
heart failure,” Kass says.
Non-systolic heart failure is characterized by fairly normal function of
the heart’s pumping action, or so-called ejection fraction, when a person is
at rest. This action falters, however, once daily physical activity begins,
and the heart becomes increasingly unable to squeeze out sufficient blood
flow to energy-starved muscles. Even small tasks, such as getting dressed in
the morning, can leave people exhausted and short of breath. Until now, Kass
notes, researchers had long thought the problem was that these hearts could
simply not relax properly, a so-called failure of their diastolic function.
The Johns Hopkins team plans to launch within the next year a national
study in the USA of the use of pacemakers in patients with this form of the
disorder, which is sometimes referred to as heart failure with preserved
ejection fraction or heart failure with normal ejection fraction.
In some cases, a combination of drug and device may work best to control
the disease, speeding up the heartbeat at times, slowing it down at other
The latest report from the Johns Hopkins team, published in the journal
Circulation online Nov. 6, follows presentation of their initial
findings at last year’s Scientific Sessions of the American Heart
Association. (For more details on that presentation, go to
People with the more common, systolic form of the disease have a pumping
function that is evenly depressed and weakened at all times, not just with
exercise or activity. Beta blockers have been proven widely effective in
minimizing the stresses placed on the failing heart during physical activity
when the body needs to more quickly squeeze out blood to the rest of the
The Hopkins study is believed to be one of the first to do a head-to-head
comparison of those with non-systolic heart failure and patients with
similar medical histories, including high blood pressure, a relatively high
ejection fraction and overgrown hearts, but no major symptoms of heart
failure. The group studied was relatively small, Kass says, and involved
mostly African Americans from the Baltimore region: Nineteen older men and
women with initial symptoms of non-systolic heart failure were compared to
17 patients with no early signs of the disease. African Americans are at
particular risk for this kind of non-systolic heart failure.
When all pedaled at increasing levels on a stationary bike, their hearts
filled with blood in a similar way. However, heart function quickly differed
in two key measures that explained why those with non-systolic heart failure
could not exercise.
Hearts of participants in the non-systolic group failed to keep up,
beating on average 44 percent less quickly during exercise than those of
participants without heart failure. Also during exercise, blood vessels in
the heart-failure group did not dilate or expand as much to meet the
increased energy demands from the body’s muscles. The corresponding
resistance to blood flow dropped 28 percent in controls as blood vessels
relaxed, but only dropped 19 percent in the heart-failure group.
In their planned study next year, the Hopkins scientists will monitor
more than 80 men and women with mild to moderate, non-systolic heart
failure. Half will be taking traditional beta blocker medications, the most
commonly prescribed treatment, while the rest will not. All will be
implanted with a pacemaker and perform exercise tests to see if their
symptoms get better — or are possibly even reversed.
If the new study validates their preliminary work, Kass predicts that his
research could change the practice guidelines about how beta blockers and
pacemakers are used in this form of heart failure.
The American Heart Association estimates that more than 5 million
Americans have some from of congestive heart failure, marked by symptoms
such as shortness of breath and fatigue.
Source: Johns Hopkins Medical Institutions