June 11th, 2013

People with Sleep Apnea at Increased Risk for Sudden Cardiac Death

Although people with obstructive sleep apnea (OSA) have an increased risk for death and cardiovascular disease, the relationship between OSA and sudden cardiac death (SCD) has not been clear. Now a new study published in the Journal of the American College of Cardiologprovides evidence that OSA is in fact associated with an increase in the risk for SCD.

Researchers at the Mayo Clinic analyzed 10,701 consecutive patients who received a first polysomnography at their institution and who had no history of SCD. After an average followup of 5.3 years, 142 people had either a fatal SCD or were successfully resuscitated. The analysis showed that people who had OSA were at increased risk for SCD and that the most severe cases of OSA had the highest risk for SCD. OSA was found to be associated with SCD even after other well known risk factors for SCD were taken into account.

Low nighttime levels of oxygen in the blood, which the researchers noted is an “important pathophysiological feature of OSA, strongly predicted SCD independently of well-established risk factors.” The researchers, who previously reported that people with OSA were more likely than the rest of the population to die from cardiac causes at night, concluded that the increase in SCD at night “may represent ‘excess’ deaths, rather than simply a shift of SCD from other times of the day to the night.”

“The prevalence of obstructive sleep apnea in Western populations is high and will likely only continue to grow given the obesity epidemic and direct relationship between obesity and sleep apnea,” said Apoor Gami, lead author of the study, in an ACC press release.


One Response to “People with Sleep Apnea at Increased Risk for Sudden Cardiac Death”

  1. Kasim Salim, MBBS MD MRCP FRCP MRCpath FRCpath says:

    Dear Larry,
    I would like to know whether the 142 patients with OSA in the SCD group were using CPAP at the time of their death and were they regular users of the CPAP machine. Was their high AHI corrected by CPAP usage at all? If these individuals had regular follow ups and their AHI were normalised in 3 to 4 weeks of starting CPAP therapy, we can’t attribute their sudden death to the hypoxia induced by OSA. Was there autopsy confirmation or exclusion of other reasons for their sudden death?