Obstructive Sleep Apnea Directly Linked to Risk for Sudden Cardiac Death
A common sleep disorder may significantly increase risk of sudden cardiac death.
When it comes to sudden cardiac death, doctors are usually most concerned about patients with pre-existing heart conditions. Having certain conditions, like heart disease or a history of heart attack, can increase risk for sudden cardiac arrest—a sudden, unexpected loss of heart function, breathing and consciousness. Without immediate treatment, sudden cardiac arrest can result in death; it accounts for an estimated 450,000 deaths each year in the United States. But according to a study published today in the Journal of the American College of Cardiology, having a common sleep disorder may increase risk for sudden cardiac death.
This study included more than 10,700 adults in Minnesota who were tested for sleep disorders between 1987 and 2003. The sleep test, called a polysomnogram, monitors heart rate and breathing during sleep and helps diagnose various sleeping disorders, including obstructive sleep apnea. Obstructive sleep apnea is the most common type of sleep apnea, which occurs when throat muscles block the airway during sleep, causing breathing to repeatedly stop and start during sleep.
Among the subjects in this study, 78% were diagnosed with obstructive sleep apnea. After following each study participant for about five years, researchers found that the usual risk factors were associated with increased risk for sudden cardiac death: increased age, high blood pressure, heart disease, heart failure and an irregular heart rhythm. But they also found that patients with obstructive sleep apnea were significantly more likely to suffer sudden cardiac death than those without the sleep disorder, and those with low blood oxygen levels during sleep were at greatest risk for sudden cardiac death.
This study adds to the body of evidence linking sleep apnea and sudden cardiac death. It is well established that certain heart conditions increase risk for sudden cardiac death, but the relationship between sudden cardiac death and sleep apnea is not as well understood. Most cases of sudden cardiac death result from an electrical malfunction in the body, which causes the heart to stop beating. But it’s possible that sleep apnea could actually be another important cause, and experts suggest that the pauses in breathing from sleep apnea may be to blame. With further research on this subject, researchers hope to develop therapies to help patients with sleep disorders reduce their risk for sudden cardiac death.
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Questions for You to Consider
How do I know if I have obstructive sleep apnea (OSA)?
A telltale sign of OSA is chronic loud snoring, interspersed with sounds of gasping or choking. Often a person isn’t aware of his or her own snoring and it will take a family member or bed partner to point it out. (Not everyone who snores has OSA, however.) Another prime indicator of OSA for most people is daytime sleepiness, although heart failure patients complain of this symptom less often.
To confirm that you have OSA, your doctor will send you to an overnight sleep laboratory for specialized testing called polysomnography. If this technology isn’t available where you live, in-home monitoring devices may be an alternative.