DALLAS Nov 18 A new generation of Medtronic
Inc's EnRhythm pacemaker programmed to kick in only when
heart rhythm disturbances are detected led to fewer deaths,
hospitalizations and incidences of developing permanent heart
problems than traditional versions of the device, according to
data from a study.
The enhanced pacing strategy had its most profound effect in
cutting the risk of developing permanent atrial fibrillation - a
dangerously irregular heartbeat - by 61 percent over the
Researchers conducting the 1,166-patient study, dubbed
Minerva, found that the new pacing strategy helped avoid the
side effects of continual electrical stimulation from standard
pacemakers, which include weakening of the heart's main pumping
chamber as well as a progression to permanent atrial
Patients in the study had a condition known as a
bradycardia, in which the heart rate is less than 60 beats per
minute, below the normal range of 60 to 100 beats per minute.
They also suffered occasional bouts of atrial fibrillation,
which if it becomes permanent puts a patient at five times the
risk of suffering a stroke.
The primary goal of the two-year trial was a reduction in a
combination of death, hospitalizations and permanent atrial
fibrillation. The more sophisticated pacemaker led to an overall
26 percent risk reduction compared to the traditional model,
which researchers said was statistically significant.
"For every 20 patients we treated, we attained saving one
patient from permanent atrial fibrillation," said Dr. Giuseppe
Boriani, lead author of the Minerva study who presented the
findings on Monday at the American Heart Association scientific
meeting in Dallas.
The incidence of permanent atrial tachycardia - a type of
heart rhythm disturbance - or atrial fibrilliation was 3.8
percent with the enhanced pacemaker versus 9.2 percent for those
with the traditionally programmed pacemaker, researchers found.
In addition, after two years 15.2 percent of those with
smart pacemakers were hospitalized and 4.6 percent died. That
compared with hospitalizations of 16.8 percent and deaths of 5.6
percent for those with the older versions of the device.
Patients with the enhanced pacemaker also reported better
quality of life and less fatigue, researchers said.
Boriani said he believed the results were definitive enough
to change medical practice so that thousands more patients
should get pacemakers with the enhanced features, which are also
available in newer pacemakers made by Medtronic that followed
the EnRhythm devices used in the study.
"This smarter pacemaker does seem to offer benefit for these
type of patients," said Dr. Robert Harrington, chairman of
Stanford University School of Medicine, who was not involved in
However, he said, "it should not be a reason to put the most
advanced pacemaker in everybody."