Electrophysiologists are increasingly acknowledging the link between atrial fibrillation and sleep apnea. At the University of Chicago, sleep center director Babak Mokhlesi, MD, MSc, and other sleep physicians work with heart rhythm specialists in a new care model that could improve patient outcomes.
As a pulmonologist and an expert in sleep disorders, Babak Mokhlesi, MD, MSc, tried for years to educate cardiologists about the correlation between untreated sleep apnea and worse outcomes for heart disease patients. He offered to do grand rounds and present at department meetings. No dice. The referrals he’d hoped for never materialized. And then something changed.
Mokhlesi, who is director of the University of Chicago Sleep Disorders Center, recently heard from the electrophysiologists who are part of the Heart Rhythm Disorders Team at the University of Chicago Heart and Vascular Center. They were planning on acquiring home sleep testing (HST) devices for checking their arrhythmia patients for obstructive sleep apnea (OSA), and they wanted to work with him on both the reading of the HST and the long-term management of these patients’ sleep disorders.
Currently, the cross-disciplinary care model they are developing has been applied to only a handful of patients. However, Mokhlesi believes it could present a growth opportunity for sleep medicine and, even more importantly, be a way to improve patient care and create better overall treatment outcomes for heart rhythm disorder patients. “Our experience at the University of Chicago was that we were trying to engage them and more recently they reached out to us,” he says.
Part of what is driving this interest is that research has reached “a critical mass,” says Virend Somers, MD, PhD, one of the top physician scientists currently studying the role of the autonomic nervous system in cardiovascular regulation, particularly as it relates to normal and disordered sleep. His team was the first to show that the treatment of sleep apnea correlated with a lower incidence of atrial fibrillation recurrence.
In the past few years, several additional studies have shown the same correlation. Atrial fibrillation is the most common type of abnormal heart rhythm, and treatment by an electrophysiologist is needed to correct the electrical misfires in the upper chamber of the heart that can ultimately lead to clots, stroke, or heart failure. Frustratingly, in some patients the condition comes back after treatment, and electrophysiologists are very interested in knowing more about factors that might predict which of their patients will suffer such a recurrence.
A 2015 meta-analysis found that the correlation between OSA treatment and better atrial fibrillation treatment outcomes was consistent across multiple retrospective epidemiological studies.1 While a carefully designed prospective randomized controlled trial would still be needed to prove scientifically that OSA treatment was actually the key factor that reduced the recurrence of atrial fibrillation, the consistency among the studies finding the same correlation is likely why the electrophysiologists have become more interested, not just at the University of Chicago but in other parts of the country, Somers says. “Ideally, we need randomized controlled trials to prove that this is indeed the correct course of action, but until we have those, it would be prudent to err on the side of caution—in other words, look for sleep apnea and treat it when we can,” he says.
Reena Mehra, MD, MS, is one of the top physician scientists studying pathways that modulate the relationship between sleep-disordered breathing and abnormal cardiac electrophysiology. She says that at a recent research presentation, she received numerous questions from the electrophysiologists in attendance. In addition, electrophysiologists at the Cleveland Clinic, where she serves as director of Sleep Disorders Research in the Sleep Center of the Neurologic Institute, have begun working with Cleveland Clinic sleep medicine specialists in a very early test model that is similar to the model at the University of Chicago. These are both welcome developments in her view.
“I think it is imperative that sleep physicians and electrophysiologists align with one another to really expedite the diagnosis and treatment of patients with cardiac arrhythmias and particularly atrial fibrillation,” she says. “The data are very strong in terms of showing a very significant association between sleep apnea and nocturnal cardiac arrhythmias that we have identified by sleep monitoring with a very large magnitude of association around the order of two- to fourfold higher odds of having these arrhythmias when the patients have sleep apnea compared to not having sleep apnea. That is even after taking into consideration confounders such as obesity, age, sex, race, and cardiovascular risk factors.”
Findings that atrial fibrillation patients with OSA who are treated with CPAP have a lower recurrence of atrial fibrillation over a 6- to 12-month time are even more compelling, she adds, because it suggests that if you have this ongoing exposure to intermittent hypoxia and sympathetic surges (rises in blood pressure and irregular heartbeat), there may be a theoretical mechanism for how sleep apnea could actually be contributing to the heart rhythm disorder.
“We are on the verge now of having the data necessary to justify performing a rigorously designed prospective randomized controlled study to better answer that question,” she says. “We were really surprised by the magnitude of association in our epidemiological work, and I think that really convinced a lot of [cardiologists, including electrophysiologists] that this is something we need to pay attention to in terms of risk prevention for atrial fibrillation.”
The Technology Factor
As important as the research component is, Mokhlesi suspects it may be one of a confluence of factors that have come together to create electrophysiologists’ interest in sleep medicine. One other key component, he believes, is technology. While electrophysiologists may long have been intrigued by research showing a correlation between sleep apnea and atrial fibrillation, they were understandably cautious about sending their patients for a possibly inconvenient and expensive attended polysomnography study. However, with newer sleep testing devices that share cardiac monitoring features with some of the home monitoring devices electrophysiologists already use, this barrier to testing atrial fibrillation patients for sleep apnea becomes significantly lower. “These patients are used to going home with devices and the electrophysiologists may have thought, ‘If we can piggyback on that, why not take advantage of it?’” Mokhlesi says.
In addition, some HST device manufacturers have begun reaching out directly to electrophysiologists. Itamar, maker of the WatchPAT device, is one company that has shared with Sleep Review that it is using this marketing strategy.
The University of Chicago Model
At the University of Chicago, the electrophysiologists plan to purchase the HST devices and provide them to the patients they believe need to be tested. The results would then be uploaded to a secure cloud-based platform where Mokhlesi and his colleagues can interpret the results. The electrophysiologists bill for the technical component of the study, and the physicians of the Sleep Disorders Center bill for the professional component.
An important feature in the model is that when the results seem problematic or produce a negative diagnosis in a patient with a high pretest probability of having sleep apnea, Mokhlesi can recommend either a repeat of the HST or a follow-up in-lab sleep study. Treatment is handled by sleep medicine specialists along with a home medical equipment provider that helps fit the patients with their OSA therapies.
Mokhlesi is well aware that some may wonder about the wisdom of handing over billing for the technical component for HST to the electrophysiologists. Indeed, he even had to sell some members of his own team on the idea. His point to them, which applies to both employee and private practice sleep medicine doctors, is the cardiologists and electrophysiologists were not sending patients to sleep medicine physicians for testing in the existing scenario, so this new scenario wasn’t any different from that standpoint.
“My perspective is that you are increasing the referral base, and at the end of the day, the electrophysiologists are not really interested in interpreting the studies or treating obstructive sleep apnea because it is a chronic condition, and they have no interest in chronically dealing with a patient’s obstructive sleep apnea. They have many other things on their plate they have to deal with, so this notion that they are taking away business from us is silly,” Mokhlesi says.
Finally, although all physicians can be somewhat territorial about their business, working collaboratively with other specialties on sleep apnea testing can simply be the right thing to do. “If you think of it from the perspective of patient care and you believe that treating sleep apnea will improve the patients’ outcomes, it is a win-win,” Mokhlesi says.
Since the University of Chicago physicians are still designing how patients will flow through the new model and the number of University of Chicago electrophysiologists who have referred patients is still very small, it remains uncertain if the model will ultimately result in more referrals of patients for treatment, Mokhlesi cautions. However, he is excited because the model could be one idea for how sleep medicine can bring testing to more patients and insert sleep health into other specialties.
“Sleep is the classic example of a multidisciplinary field because it applies to so many different specialties,” Somers adds. “I think sleep is relevant to cardiology, renal disease, endocrinology, and erectile function and urology….The cardiology approach may serve as a template for other disease conditions to look for sleep apnea, and I think what Dr Mokhlesi and his colleagues are doing is a very important contribution to developing this strategy.”
Is It Appropriate?
Of course, the other concern with the model is whether it actually is in the best clinical interest of the patients. The American Academy of Sleep Medicine (AASM) official guidelines on HST do currently state that home testing is not appropriate in the case of patients with certain heart disorders.
Mokhlesi is a member of the AASM and is sensitive to this concern, but he is also conscious of the fact that after years of advocating for sleep testing of cardiology patients, he finally is seeing a model that can get more of these patients tested. Although it may not be the gold-standard in-lab study, home testing is better than nothing, which is what these patients had previously, he posits. “I am not saying that every patient is a good candidate to have a home sleep study,” he says. “No question about it, some people need to come to the sleep lab. But for certain conditions, it is reasonable to do home sleep testing. I don’t want to be dogmatic and say everybody who has a history of heart failure and everybody who has a heart rhythm problem should never do a home sleep study. That kind of blanket recommendation is also problematic.”
Mehra is part of the AASM group currently reviewing the HST guidelines and notes that the original recommendations were made with the best available data at the time, but that this was limited. In the absence of research evidence showing HST to be appropriate for people with cardiac conditions, the AASM could not recommend HST for these patients. Now that more data on HST are available, the original recommendations may be updated.
“I recognize that what [Mokhlesi] is doing is viewed as controversial, but on the other hand, we really want to assure the most efficient care paths for diagnosing and treating these patients,” Mehra says. “The clinicians are very busy, and to incorporate another potential target in terms of diagnosing and treating, we have to make it easy for them. The key, as it is with any home sleep apnea testing, is to ensure that if that home sleep apnea test is negative, the patient needs to go to the sleep laboratory for formal attended polysomnography to really verify that they don’t have sleep apnea.”
Another potential problem is that there are no sleep apnea screening tests validated for use on cardiology patients. Instead, clinicians must use individual judgement on who is most likely to benefit from sleep apnea testing and who among these patients is a good candidate for being able to perform the test at home.
Mokhlesi has found that the home sleep studies ordered and conducted by the electrophysiologists had a somewhat higher rate of failure, possibly because they were less experienced with both the technology and with what types of patients make the best candidates for HST. However, the benefit of more patients being screened and tested is likely to outweigh the downside of a somewhat higher failure rate and greater need for follow-up testing, he believes.
Heart and Sleep: The Big Picture
What should matter most at the end of the day is what is best for patients, and Mokhlesi also hopes that a stronger relationship between sleep medicine—a relatively young field—and cardiology—which is more mature—could lead to exactly the type of outcome research he, Mehra, Somers, and many others believe is needed to answer the big questions about when sleep-disordered breathing treatment is useful and which individual patients are most likely to be helped by it.
According to Mehra, there is even the potential that sleep apnea testing could create more personalized medicine in atrial fibrillation care if research can determine that specific atrial fibrillation treatments work better in the OSA population.
To test all of these potential new patients, medicine needs new innovative care models, Somers adds. “The logistics of the number of people involved is going to demand that we have a more economical and widely available sleep apnea test, at least a screening test for sleep apnea,” he says. “I think this is something that is going to evolve. It is going to be determined by standard of care, what is economically feasible, and what kind of patient numbers we are talking about. I don’t know if there is a right answer at this point. It is going to have to evolve with trial and error.”
Part of this trial and error is being done by Mokhlesi and his colleagues at the University of Chicago.
Lena Kauffman is a freelance writer and former Sleep Review editor based in Ann Arbor, Mich.
1. Shukla A, Aizer A, Holmes D, et al. Effect of obstructive sleep apnea treatment on atrial fibrillation recurrence: a meta-analysis. JACCCEP. 2015;1(1):41-51. doi:10.1016/j.jacep.2015.02.014.