November 6, 2009

Study suggests sleep apnea, arrhythmia relationship

Study suggests sleep apnea, arrhythmia relationship

Vanderbilt cardiologist Ken Monahan, M.D., is the lead author of a study to help determine if sleep apnea, and the breathing disturbances associated with it, can trigger certain types of arrhythmia.

The findings were reported in the Nov. 3 issue of the Journal of the American College of Cardiology.

“Our study extends previous work that has shown an association between sleep apnea and certain types of arrhythmias,” Monahan said. “There is a clear temporal relationship between when the respiratory events that are the hallmarks of sleep apnea occur and subsequent episodes of abnormal heart rhythm.”

Monahan was part of a team of researchers that included Jeff Rottman, M.D., an electrophysiologist at Vanderbilt, and Susan Redline, M.D., director of the University Hospitals Sleep Center in Cleveland. The group examined 2,816 polysomnograms from the Sleep Heart Health Study and screened the sleep studies for atrial fibrillation and nonsustained ventricular tachycardia, two common forms of abnormal heart rhythm.

Fifty-seven participants experienced 62 arrhythmias (some more than one). The odds of an arrhythmia occurring shortly after a respiratory disturbance were nearly 18 times the odds of an arrhythmia occurring after normal breathing, the authors wrote. They also looked at the timing of the arrhythmias.

“We looked at arrhythmias that occurred within a certain time frame of the respiratory events. Based on prior studies, we chose a 90 second window after a respiratory event to look for abnormal heart rhythms,” Monahan said.

Over the last 10 years there has been a growing body of evidence indicating that sleep apnea has deleterious effects on the cardiovascular system, and this study is not the first to suggest or comment on the relationship between the two, Monahan said. The goal of this study was to determine if there is something about the sleep apnea episodes that increases the risk of arrhythmia.

The study demonstrates that, across the range of sleep disordered breathing, the risk of arrhythmia is increased shortly after the occurrence of apneas and hypopneas during sleep, the authors wrote.

“This provides further evidence that we should ask patients newly diagnosed with certain types of arrhythmia questions regarding sleep apnea,” Monahan said. “If there is suspicion of sleep apnea, it would be reasonable to refer them to a sleep expert or for a sleep study.”