A survey conducted by the International Collaboration of Sleep Apnea Cardiovascular Trialists takes the pulse of cardiologists’ in 16 countries regarding sleep apnea diagnosis and treatment for their atrial fibrillation patients.

By Jane Kollmer

Sleep apnea is highly prevalent among patients with cardiovascular disease. Obstructive sleep apnea (OSA), in particular, has been closely associated with serious cardiac conditions, including hypertension, coronary artery disease, congestive heart failure, stroke, and atrial fibrillation.

Recently, the International Collaboration of Sleep Apnea Cardiovascular Trialists (INCOSACT) surveyed cardiologists from around the world to evaluate their attitudes and beliefs about OSA in relation to patients with atrial fibrillation (AF). 

“For sleep clinicians, results from this study indicate that cardiologists recognize the importance of sleep apnea as targetable risk factor in AF,” says Reena Mehra, MD, MS, INCOSACT member and director of sleep disorders research at the Cleveland Clinic.

INCOSACT was founded as a collaborative effort to promote high-quality clinical trials in sleep apnea and cardiovascular disease via sharing resources including harmonization of data, expertise, and dissemination of methods and outcomes to the scientific community. Susan Redline, MD, MPH, from Harvard University, and Douglas McEvoy, MD, from the Adelaide Institute for Sleep Health at Flinders University in Australia, co-chair it.

The sleep apnea-atrial fibrillation survey, reported in the International Journal of Cardiology Heart & Vasculature in October 2022, had three objectives. The first, to conduct a global online survey to determine cardiologists’ perceived importance of recognizing and treating OSA to improve the management of atrial fibrillation. The second, to evaluate whether current professional guidelines for atrial fibrillation management reflect real-world beliefs and practices among cardiologists. Third, to gauge the level of interest among cardiologists in participating in randomized controlled trials to clarify evidence for OSA treatment to improve atrial fibrillation outcomes.

“It was surprising that although there was need for stronger evidence to support current recommendations, there was not clear equipoise to treatment of sleep apnea in atrial fibrillation with most respondents indicating that treatment of sleep apnea reduced adverse AF outcomes,” Mehra says.

Assessing Risk Factors and Treatments

INCOSACT distributed the survey between January 2019 and June 2020 to practicing cardiologists in Australia, Brazil, Canada, China, France, Germany, Hong Kong, Japan, New Zealand, Singapore, Spain, Sweden, Taiwan, Turkey, the United Kingdom, and the United States. “It is important to obtain diversity of perspective in terms of the approach to clinical care of the patient with suspected sleep apnea from cardiologists,” Mehra says. 

Approximately-two-thirds of the 863 respondents were from the United States, Japan, Sweden, and Turkey. Almost half were general cardiologists, a quarter electrophysiologists, and the remainder interventional cardiologists, heart failure specialists, cardiac imaging experts, and “other.”

According to the cardiologist-respondents, most risk factors for first atrial fibrillation or atrial fibrillation recurrence were “extremely important” or “very important.” Of the 12 risk factors listed, respondents selected congestive heart failure as the most important risk factor and OSA as the third most important.

The treatments reported to fail most often were atrial fibrillation anti-arrhythmic drug therapies, followed by cardioversion failure and ablation procedures.

Mixed Opinions on OSA Referrals

The survey then dug into factors influencing referral practices for OSA diagnosis and treatment within the context of atrial fibrillation management.

Overall, one-third of atrial fibrillation patients were referred for OSA diagnosis with less than half of those undergoing full polysomnography. For all referred patients, nearly half were diagnosed with OSA. However, less than two-thirds of OSA-diagnosed patients were recommended for CPAP treatment. Of these, less than half ultimately using CPAP.

Access to OSA diagnostic and treatment services were deemed “easy” or “very easy” by more than half of the respondents. In contrast, 40.1% found access either “difficult” or “very difficult.” In a sub-analysis, respondents in Australia, Germany, Japan, Spain, Sweden, and the United States found access mostly “easy” or “very easy.” But respondents in Brazil, Taiwan, and Turkey found access “mostly difficult” or “very difficult.”

Moreover, 39% of 801 respondents confirmed that the success of OSA treatment with CPAP was a factor in deciding whether to refer their patients for OSA diagnosis. In contrast, nearly half (~49%) were not influenced by OSA treatment success.

“I was surprised at the low percentages of referrals for sleep testing coupled with the broad recognition of the association between [atrial fibrillation] and OSA and the relative lack of consistency in OSA treatment,” says Lee A. Surkin, MD, FACC, FCCP, FASNC, FAASM, founder of the American Academy of Cardiovascular Sleep Medicine, chief medical officer of VirtuOx, and president of Empire Sleep Medicine in New York.

Surkin, a board-certified cardiologist and sleep physician who was not involved in the survey, says all of his atrial fibrillation patients are sleep tested and treated. “My long-term success in treating [atrial fibrillation] is excellent in those with OSA who are aggressively treated with either CPAP or oral appliance therapy,” he says.

Cardiologist-sleep specialist Barbara Hutchinson, MD, PhD, FACC, president of Chesapeake Cardiac Care and a board chair of the Association of Black Cardiologists, says the survey illustrates the need for more education and collaboration between sleep physicians and cardiovascular specialists.

Like Surkin, Hutchinson, who was not involved in the survey, says all of her patients have a sleep study before procedures for atrial fibrillation. As the survey revealed, not all cardiologists practice this way.

Importance of Treating Sleep Apnea?

The survey’s final section gauged cardiologists’ views on the need for further research linking OSA with atrial fibrillation clinical trials quantifying OSA treatment impact on atrial fibrillation outcomes, and whether OSA treatment can mitigate adverse atrial fibrillation outcomes.

Nearly 80% of respondents considered it “extremely” or “very” important to conduct further research into the benefit of treating moderate to severe OSA with CPAP for preventing or managing paroxysmal or a first atrial fibrillation episode. In contrast, less than 40% prioritized research for OSA treatment in aiding the managing of permanent atrial fibrillation.

Respondents ranked stroke reduction (40.8%) and atrial fibrillation recurrence (38.5%) as the two most important atrial fibrillation health outcomes that needed testing in future randomized clinical trials. Reducing atrial fibrillation burden (26.3%) was ranked the lowest in importance.

Despite the polarized view that CPAP is best for improving/reducing risk for outcomes, nearly 70% of respondents believed randomized controlled trials of OSA treatment in atrial fibrillation patients were necessary and indicated they were still willing to randomize their patients in multi-national clinical trials to determine whether adding CPAP to usual care is best.

INCOSACT found that the majority of cardiologists surveyed expressed certainty that combined OSA and atrial fibrillation treatment is superior to atrial fibrillation treatment alone for improving atrial fibrillation outcomes. However, a minority of surveyed cardiologists referred atrial fibrillation patients for OSA testing. And while half of screened atrial fibrillation patients had OSA, CPAP was prescribed in little more than half of them.

Cardiologist-sleep specialist-intensivist Younghoon Kwon, MD, MS, FACC, who was not involved in the survey, says it is unclear whether screening every atrial fibrillation patient is right, but the bigger issue is finding alternative therapies for patients who cannot tolerate CPAP.

“We do not have evidence to show that treating OSA would result in better outcomes. So sleep clinicians and cardiologists should be careful in saying this,” says Kwon, associate professor in the division of cardiology at the University of Washington. “This cannot be simply assumed based on anecdotal experiences.”

He says research trying to ascertain the independent relationship between OSA and atrial fibrillation is needed because, due to many confounders, it is not yet certain whether OSA is an independent risk factor for incident atrial fibrillation. “What we have mostly is some evidence that OSA is associated with higher risk of [atrial fibrillation] recurrence following ablation,” Kwon says.

Surkin says, “This should further support the need for interdisciplinary collaboration between sleep physicians and cardiologists not just for [atrial fibrillation] but for all other cardiovascular diseases. This not only involves OSA, but there are data showing strong associations between insomnia and [cardiovascular disease] and other sleep disorders, such as narcolepsy and restless legs syndrome.”

Future Clinical Trials

“Our results underscore the need for larger, multi-national prospective studies of OSA treatment and [atrial fibrillation] outcomes to inform more uniform society guideline recommendations,” the authors write. “Taking this a step further, our findings suggest that large, well-designed, prospective randomized studies of the impact of sleep apnea screening and treatment in the atrial fibrillation population are wanted and feasible.”

But “feasible” and “large” may well be in the eye of the specialty.

“This topic highlights that cardiologists and sleep researchers speak a different language,” says cardiologist-sleep specialist Alan Steljes, MD, FACC, who oversees the sleep medicine division of Nevada Heart & Vascular Center. “Cardiologists, and the writers of clinical guidelines, rely on prospective randomized trials to validate treatment strategies. These trials involve large numbers of patients followed over a prolonged period of time. Sleep research studies however, are typically observational in design, or involve small numbers of patients with surrogate endpoints.”

Low CPAP adherence is the biggest hurdle to large-scale trials, according to Steljes. Patient access to counseling and follow-up to optimize CPAP adherence should be included in clinical trial enrollment criteria, he says.

Hutchinson suggests adding an arm to ongoing cardiovascular trials—especially if they use devices that can measure sleep. 

From INCOSACT’s perspective, Mehra says ongoing discussions are occurring about conducting a pilot and larger randomized clinical trials in sleep apnea and atrial fibrillation, leveraging the strength of the INCOSACT network.


Faulx MD, Mehra R, Reis Geovanini G, et al; International Collaboration of Sleep Apnea Cardiovascular Trialists INCOSACT. Obstructive sleep apnea and its management in patients with atrial fibrillation: An International Collaboration of Sleep Apnea Cardiovascular Trialists (INCOSACT) global survey of practicing cardiologists. Int J Cardiol Heart Vasc. 2022 Jul 19;42:101085.