A "smart" pacemaker that kicks
in only when a person's heartbeat becomes irregular can be more effective in
preventing further heart damage than standard pacemakers that are always at
work, researchers report.
These highly programmed pacemakers
reduced by 26% patients' risk of death, hospitalisation for heart disease and
permanent irregular heartbeat, according to late-breaking research presented at the American Heart Association annual meeting in Dallas.
"The more sophisticated
pacemaker technology proved to be superior to the current standard of
care," said study co-author Dr Giuseppe Boriani, a professor at the
Institute of Cardiology at the University of Bologna, Italy.
Standard pacemakers are used to
continually regulate the heartbeat in people with bradycardia, a condition in
which the heart beats slower than 60 beats per minute.
Irregular heartbeat problems
More than 128 000 people in the
United States suffer from irregular heartbeat problems like bradycardia, and
those cases account for about half the pacemakers implanted in the United States,
But the old-style pacemakers and
their constant stimulation increase a person's risk of one of bradycardia's
common complications, a rapid and irregular beating of the heart's upper
chambers known as atrial fibrillation.
Heart patients with atrial
fibrillation run a higher risk of heart failure, stroke and death.
Doctors have been experimenting with
different methods to use pacemakers to stimulate the heart's upper chambers
(the atria) and the heart's lower chambers (the ventricles) in a way that
prevents atrial fibrillation.
This study focused on 1 166 patients
who received pacemakers programmed in one of three different ways:
One program performed standard
pace making, which sends electrical pulses to both chambers of the heart. Another focused on pace making
that would stimulate both the atria and the ventricles if the pacemaker
sensed that an episode of atrial fibrillation was imminent. The third combined that second
approach with an additional feature: a number of different programs that
stimulated the atria to both head off an irregular heartbeat and to
restore normal heart rhythm.
The third program, which focused on
a varied, off-and-on approach to the whole heart, was superior to the other
two. By the end of the two-year study, it had reduced by 61% the number of
heart patients who developed permanent atrial fibrillation.
Further evaluation needed
Over the next two years, just over
15% of those with smart pacemakers were hospitalised and 4.6% died, compared to
nearly 17% hospitalisations and 5.6% deaths for those without smart pacemakers.
The patients provided with smart
pacemakers also reported that they felt less fatigue and enjoyed better quality
This breakthrough came after a couple
of dozen studies of different pacemaker programs that had shown no benefit,
said Dr Anthony Tang, a professor of medicine at Western University Canada in
"It was a bit disappointing
that it didn't universally show positive effect," Tang said of previous
research. In this study, doctors appear to have figured out the best programmes
that will cause the pacemaker to kick in at the right time and for the
appropriate heart chamber.
Boriani said this sort of pacemaker
programming should be further evaluated.
"If applied to all patients
requiring pacemakers, the benefits could help many thousands of patients in
every country," he said.
The research was funded by
Medtronic, a pacemaker company that provided the pacemakers used in the study.
Visit the American Heart Association
for more on heart pacemakers.