Sleep Apnea Multiplies Risk of Arrhythmias Like Atrial Fibrillation

October 31, 2009 5:21 AM CT

By Peggy Noonan and Mellanie True Hills

New research shows sleep apnea, a disorder that disrupts breathing during sleep, increases the risk of having arrhythmias.

Sleep apnea is believed to be linked to atrial fibrillation (AF) but until now, we didn’t know if apnea could actually trigger arrhythmias like afib.

The new study looked to see if arrhythmias were increased or triggered by discrete episodes of apneas or hypopneas (breathing pauses), says coauthor Susan Redline, MD, MPH, of Case Western Reserve University in Cleveland, Ohio.

“Our focus was on individuals with mild to moderate apnea since it is in those people that we could compare periods of sleep where there were no apneas to periods where apneas occurred. Prior studies that showed increased arrhythmias did not do this temporal analysis,” Dr. Redline explains. They just “looked at overall number of arrhythmias per night in patients with severe sleep apnea.”

Her team examined data from the Sleep Heart Health Study (SHHS), a multicenter long term study whose goal was to investigate the cardiovascular consequences of sleep disordered breathing. They identified 57 people in the SHHS study who had paroxysmal atrial fibrillation, or recurring episodes of AF lasting less than 7 days, or nonsustained ventricular tachycardia (NSVT), the rapid beating of one of the heart’s ventricles that lasts for less than 30 seconds.

The SHHS data included each person’s total sleep time, number of episodes of sleep apnea or hypopnea (shallow or reduced breathing), average oxygen saturation, stage of sleep, and related factors. Electrocardiogram records were reviewed to indentify episodes of arrhythmias.

Three-fourths of arrhythmias were nonsustained ventricular tachycardia, and two-thirds of all arrhythmias occurred during non-REM sleep, the dreamless stage that usually represents about 80% of a night’s sleep.

The study, published in the Journal of the American College of Cardiology, showed the odds, or risk, of having an abnormal heartbeat were 18 times higher immediately after an apnea episode compared to during normal sleep breathing.

Sleep-disordered breathing (apnea or hypopnea) did not have to be severe to raise AF risk. In the study’s discussion section, the authors say: “…neither the severity of SDB (sleep-disordered breathing) nor the severity of individual respiratory disturbances needs to be extreme to increase the risk of arrhythmia.”

This work “underscores the tight link between heart disease and sleep apnea and the need to further evaluate the impact of sleep apnea treatment on reducing heart disease burden,” Dr. Redline states.

Comments: We believe that the following comments in the discussion section of the study are particularly significant for those with afib, or who may be at risk for afib.

It is possible that risk is not evenly distributed in the population and that the rate of SDB (sleep disordered breathing)-associated arrhythmias may be even higher among patients with impaired cardiac function or with other risk factors that enhance their vulnerability to physiological stressors.

The high relative risk may provide insights into prior studies demonstrating adverse cardiovascular outcomes in patients with SDB, including AF. Our results reveal a significant association between the risk of PAF (paroxysmal atrial fibrillation) and the presence of a respiratory disturbance within the pre-defined hazard period. Significant associations between AF and SDB have been previously reported; specifically, SDB is a risk factor for incident AF and for recurrence of AF after electrical cardioversion. Repeated exposures to intervals of relatively high risk for PAF, both within a given night and over many nights, may result in an increasing cumulative burden of discrete PAF episodes over time. Each of these paroxysms may increase the propensity for further and sustained episodes of AF due to electrical remodeling within the atria. Therefore, untreated SDB may serve as an ongoing source of AF stimulation, leading ultimately to initiation or recurrence of clinically significant arrhythmia. Correspondingly, it is plausible that treatment of underlying SDB may inhibit progression of subclinical PAF to a more detrimental form of the arrhythmia.

A marked rise in the prevalence of AF is anticipated in coming years, with ~60% of that increase estimated to be attributable to obesity. Our data, which temporally link SDB events and the risk of PAF, suggest that unrecognized SDB may be a contributing factor to the projected increase in AF due to obesity.

From these researcher insights it is reasonable to conclude that sleep apnea could be one of the reasons that “afib begets afib”, and that the treatment of sleep apnea could inhibit progression from paroxysmal to persistent atrial fibrillation. Obviously more research is needed.

Here at StopAfib.org, we know from personal experience that sleep apnea treatment isn’t always easy, especially traveling with it. I personally will be very thankful if the day comes that I no longer have to submit to “explosives inspection” of my CPAP before every flight. However, treating sleep apnea is far less challenging than treating afib, and is a very small price to pay for keeping the afib beast at bay.

Because afib and sleep apnea so often go hand-in-hand, and treating sleep apnea can be so challenging, we’ve created an Afib and Sleep Apnea discussion in the StopAfib.org forums so we can help each other. Please join us. You’ll find us here:

To read more about the study, see:

To read more from StopAfib.org about atrial fibrillation and sleep apnea, see:

To view an animated illustration showing how sleep apnea affects breathing, see:

  • What Is Sleep Apnea? (from the National Heart, Lung and Blood Institute, a division of the National Institutes of Health)

Peggy Noonan specializes in writing about health for consumers and medical professionals. She writes for leading national magazines and consumer publications as well as StopAfib.org.

Mellanie True Hills is founder and CEO of StopAfib.org and an atrial fibrillation survivor.