Cardiac deaths peak during sleep for those with sleep apnea

Reported by Susan Aldridge, PhD, medical journalist

People with sleep apnea are more likely to die of a heart attack during the night, compared to the rest of the population.
The peak time for a heart attack is in the early morning, up to noon. This is because of daily fluctuations in the physiology of the heart and circulation. However, this is not so in the case of sleep apnea, according to a new study from the Mayo Clinic.

In sleep apnea, someone will stop breathing many times in the night because of an obstruction to their upper airway. The condition has been linked to heart problems. In the current study, a group of patients attending the Mayo Clinic Sleep Center who had died of cardiac arrest were studied. Of those who had had sleep apnea, 54 per cent died between 10 pm and 6 am while only 27 per cent of those who did not have sleep apnea died between these hours.

The researchers are not sure if sleep apnea makes cardiac arrest more likely or just shifts the time when it occurs. They are also not clear whether treatment for sleep apnea can alleviate the risk. The study underlines the importance of diagnosing and treating sleep apnea wherever possible.

Source
The Mayo Clinic 23rd March 2005