Obstructive Sleep Apnea Linked to Risk Of Atrial Fibrillation Before Age 65
Many markers of heart disease—notably hypertension, elevated levels of C-reactive protein, and systemic inflammation—occur with sleep apnea, according to Dr. Somers. Consequently, he maintained, it makes sense that an untreated apnea could lead to cardiovascular disease.
In addition to his work showing a link with atrial fibrillation, he cited studies associating sleep disorders with hypertension, sudden cardiac death, and heart failure. He noted the following:
▸ Apnea can cause hypertension, and hypertension becomes worse if apnea is not treated (N. Engl. J. Med. 2000;342:1378–84).
▸ Obstructive sleep apnea patients were two to three times more likely to have a first-degree relative who died of a heart attack or suddenly of an unexplained cause, according to a review of 500 people by Dr. Somers and his colleagues.
▸ Although 6 a.m.-11 a.m. is the peak time for sudden cardiac death in the general population, 46% of sudden cardiac deaths in people with obstructive sleep apnea occurred between midnight and 6 a.m. (N. Engl. J. Med. 2005;352:1206–14).
About 10% of heart failure patients have obstructive sleep apnea and 40% have central sleep apnea, Dr. Somers added, attributing the data to studies conducted during the 1990s. “Since then,” he said, “patients are substantially fatter, and we think there are more obstructive apneas in heart failure patients than there used to be.”
Although Dr. Somers believes in treating sleep disorders to prevent heart disease, he added that his colleagues in cardiology won't be convinced until cause and effect is proved.
As for randomized, controlled trials providing that proof, a major obstacle is that institutional review boards are not likely to approve a trial that allows a sleep disorder to go untreated because the patient is randomized to a control group.
“It's a double-edged sword,” Dr. Somers said. “They force you to treat everybody, so you can't do the study. But until you do the study, not everybody will be treated.”
