Apnea linked to heart rates in new study
APNEA SUFFERERS stop breathing for 10 seconds to a minute or more, a condition that can rouse them hundreds of times a night. Apnea sufferers tend to snore loudly The condition can leave people exhausted by day and in danger of dozing off while driving. Scientists also believe apnea contributes to high blood pressure and heart disease. But a team of French doctors, led by cardiologist Stephane Garrigue, found in a study that faster heart rates caused by pacemakers can relieve apnea.
That stands on end the prevailing theory that apnea acts on the heart. It means the heart can also act on apnea.?In patients with normal heart rhythm, maybe it?s the occasion to develop some drugs to increase the heart rate,? Garrigue said.
The findings, reported in Thursday?s New England Journal of Medicine, have intrigued doctors.
?If you had asked me about this, I would have said it was a long shot,? said Dr. Jeffrey Drazen, a respiratory specialist and editor in chief of the journal Garrigue?s medical team at the University of Bordeaux studied 15 heart patients who showed symptoms of sleep apnea.
Pacemakers kick in when the heart slips below a certain number of beats per minute. For the study, the researchers increased that number by 15 beats per minute. In this overdrive setting, the patients? hearts would turn on the pacemakers when the rate dropped to around 70 beats a minute. On the overdrive setting, the average hourly number of nighttime breathing lapses dropped 61 percent, from 28 to 11. ?We were very surprised to have this kind of effect,? Garrigue said. Garrigue and other doctors suggested that the faster heart rates may be stimulating various nerves, which then prompt the brain to normalize breathing.
The Garrigue team, which said it was still trying to confirm the theory , said the technique could relieve sleep apnea in people who already have an adjustable pacemaker. But whether pacemakers should be used as a treatment for apnea ?remains to be determined.? Estimates vary on the number of people who suffer from sleep apnea, where breathing ceases and the sufferer is forced to wake up to resume breathing. More than 10 percent of people over 65 are believe to experience it. Some estimates suggest it may affect 10 percent to 20 percent of middle-age people. It can be caused by soft tissue that flops into the throat and cuts off breathing, or originate in the central nervous system when the body simply stops trying to breathe.
PACEMAKER PATIENTS INSPIRE STUDY
It was pacemaker patients themselves who inspired the study. They reported that after getting their pacemaker, they were sleeping better and not waking up as much at night.
Many cases of sleep apnea appear when the soft palate, the tonsils or the base of the tongue blocks the airway, and the Garrigue group didn?t expect the extra heartbeats to help people suffering from apnea caused by a physical obstruction. Nonetheless it did, which is why ?the mechanisms involved remain to be explained.? Doctors also need to discover if the pacemaker technique lowers the incidence of heart problems linked to sleep apnea.
APNEA TREATMENTS
Mild cases can often be treated with dieting and sleeping on the stomach or side. Other patients may wear air-pumping masks at night or even undergo surgery to remove a blockage in their airways, but that only works in 38 to 50 percent of the cases. Dr. Daniel Gottlieb, a respiratory and sleep specialist at Boston University School of Medicine, said the findings suggest apnea might be treatable with drugs, perhaps by quickening the heart or activating the respiratory control center of the brain. However, Dr. Richard Waldhorn, medical director of the Sleep Disorder Center at Georgetown University Hospital in Washington, cautioned that the pacemaker overdrive may relieve apnea mainly in patients with heart problems, too.
The Associated Press and Reuters contributed to this report.
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