WEDNESDAY, May 7, 2003 (HealthDayNews) -- A pacemaker seems to do no particular good for people who faint frequently because something is wrong with their nervous system, a Canadian study finds.
It's a striking result, since it comes from researchers whose previous studies indicated a pacemaker would reduce the number of fainting spells.
This is the one to believe, says Dr. Stuart J. Connolly, a professor of medicine at McMaster University in Ontario and lead author of a paper reporting the results in the May 7 issue of the Journal of the American Medical Association.
"The earlier studies didn't have as rigorous a methodology," Connolly says. "It was randomized, but patients knew what group they were being assigned to."
Frequent fainting -- the medical term is vasovagal syncope -- is "somewhat subjective," Connolly says. "A patient comes in and tells you it happened. In the original studies, the patients who did not get pacemakers were somewhat disappointed. Those psychological effects might have had an effect on the results."
All of the 100 patients enrolled in the study at 15 medical centers had pacemakers installed. But half of the pacemakers were programmed just to monitor the heart, while the others were programmed not only to detect events that might cause fainting but also to respond to them.
So the six-month incidence of fainting spells was 40 percent in the monitor-only group and 31 percent in the other group, a reduction of 30 percent. But that result is not as clear-cut as it might seem, Connolly says.
"The fact that you can't prove that something works is not the same as proving that it doesn't work," he says. "We're saying that it is not a treatment that you can be absolutely sure will work. The best evidence is that it doesn't work particularly well."
Fainting is surprisingly common, Connolly says; maybe a third of all people have fainted at one time or another. But the number of people with recurrent severe vasovagal syndrome, to give it its full medical name, is small.
He still might prescribe a pacemaker for some patients, Connolly says, but only as a treatment of last resort. The first treatment is general psychological support, with medications prescribed if the fainting spells continue. "Then if they still continue, we might discuss a pacemaker," he says.
Dr. Jose M. Dizon, who works in the Syncope Center at Columbia-Presbyterian Medical Center in New York, agrees with that approach.
"We've had cases that were refractory to ordinary treatment where a pacemaker did help," says Dizon, a professor of clinical medicine and surgery at Columbia. "But it's not a situation where you put them in willy-nilly. In the general population of people with vasovagal syndrome, it would help only a small group."