Experimental Treatment for Sleep Apnea Disappoints
Using a pacemaker to speed up heart rate failed to produce desired result, study finds
WEDNESDAY, Dec. 14, 2005 (HealthDay News) -- What seemed like a promising treatment for sleep apnea -- using an implanted device to make the heart beat faster -- doesn't appear to be working out, a new study found.
Two years ago, French physicians said the method, called atrial overdrive pacing (AOP), had produced significant improvement in some people with sleep apnea.
Sleep apnea involves frequent stoppages of breathing that not only disturbs sleep but also increases the risk of stroke, heart attack and death.
But now Greek physicians report that their trial with 16 sleep apnea patients found the intervention "has no significant effect." They published their findings in the Dec. 15 issue of the New England Journal of Medicine -- the same journal that carried the initial report of AOP's success.
A similar finding will be forthcoming from physicians at Baylor College of Medicine, who last year reported some initial success in the use of AOP for sleep apnea.
"Our initial report was on 13 patients, two of whom had a significant response," said Dr. Hossein Sharafkhaneh, assistant professor of medicine at Baylor. "Subsequent to that, we enrolled more patients and they did not respond. The effect of AOP was not significant enough for it to be considered a treatment option."
A report on the trial is being prepared for submission to a medical journal, he said.
The Greek trial, conducted by doctors at Heraklion University Hospital, Crete, compared AOP with the standard treatment for sleep apnea -- continuous positive airway pressure (CPAP), in which air is delivered through a special mask or pillow.
All the people in the trial already had pacemakers. They were randomly assigned either to have the pacemaker programmed so that their heart beat 15 times more a minute than normal or to leave the pacemaker alone and have CPAP. After a month, the two groups switched therapies.
"During AOP, no significant changes were observed in any of the respiratory variables measured," the researchers reported. By contrast, CPAP gave substantial improvements in sleep quality, in an index of breathing quality and in self-reported daytime sleepiness, a constant problem for people with sleep apnea.
Despite the negative report, an accompanying editorial in the journal by Dr. Daniel J. Gottlieb, assistant professor of medicine at Boston University School of Medicine, said that AOP might be useful for a subset of patients --those whose sleep apnea is caused by a defect in the central breathing control system.
In most cases, sleep apnea is due to physical blockage of the airways, which is why it is a growing problem as more Americans become obese. The condition is estimated to affect two percent of middle- aged women and four percent of middle-aged men.
But sometimes sleep apnea is caused by "instability in ventilatory control," Gottlieb said, and that problem often is associated with congestive heart failure. While AOP "is likely to have at most a very limited role" in treating sleep apnea caused by blockage, it's likely that it can play a useful role for some other patients, he said.
Find out more about sleep apnea at the National Library of Medicine.