By now, everyone knows that sleep – both the quality and quantity – has a direct impact on physical and mental health.
As the importance of sleep has gained clinical and consumer attention, sleep apnea has been revealed as a dangerous and potentially life-threatening condition that often goes undiagnosed. At the same time, the prevalence has increased over the past ten years parallel with the growing rates of obesity and being overweight which are risk factors.
The link between sleep apnea and atrial fibrillation
Significant research now also links the most common type of sleep apnea – obstructive sleep apnea (OSA) – to atrial fibrillation (AF). In fact, both conditions share some of the same risk factors including age, weight, and having diabetes. This link has implications for testing, diagnosis, treatment, and management for both sleep apnea and AF.
What is sleep apnea?
Sleep apnea is a disorder where breathing stops or becomes dangerously shallow during sleep. OSA occurs when the muscles in the back of the throat relax and the upper airway narrows or closes when you’re trying to breathe in.
Sleep apnea affects about 60 million people in the US and 986 million worldwide. Experts believe approximately 85% of all patients with sleep apnea go undiagnosed.
According to the Mayo Clinic, if you snore loudly and wake up tired after a full night’s sleep, you may have sleep apnea.
How is sleep apnea diagnosed?
There are two ways to test and diagnose sleep apnea:
- Nocturnal polysomnography
- Home Sleep Apnea Test (HSAT) kits.
The former is performed, usually overnight, in a sleep disorder clinic. You are hooked up to equipment that monitors your breathing patterns, heart, lung and brain activity, blood oxygen and arm and leg movements while you sleep.
Home sleep tests are generally easy to use, inexpensive, and usually measure your airflow and breathing patterns, heart rate and blood oxygen level.
What is atrial fibrillation?
Atrial fibrillation (AF) is an irregular, often rapid, abnormal heart rhythm that affects 2.5 million people in the U.S. and 33.5 million people worldwide. It’s caused by disorganized or chaotic electrical signals, which make the upper chambers of the heart (the atria) quiver, instead of contracting properly.
Those with AF have a stroke risk that is five times higher than people who do not. The risk factors for developing AF include age, being overweight and having other health conditions such as diabetes. Obstructive Sleep Apnea can now be added to the list as a relatively new defined risk factor.
The Relationship Between OSA and AF
According to the Heart Rhythm Society – a professional society of electrophysiologists (EP) – understanding the exact relationship between AF and sleep apnea is evolving. Estimates suggest that half patients with AF also have sleep apnea and patients with sleep apnea have four times the risk of developing AF.
Over time, if sleep apnea is left untreated, it increases the risk of other conditions, including
- atrial fibrillation
There’s also evidence that sleep apnea increases the frequency of arrhythmias that occur during sleep. 
How does sleep apnea cause atrial fibrillation?
According to Patricia Tung, M.D. and Elad Anter M.D.
“the mechanisms by which sleep apnea precipitates AF or vice versa, remain unclear.”
They discuss the latest thinking in what they call this “dual epidemic” looking at current data linking the two conditions and suggest approaches for screening AF patients for sleep disorders. 
How the two conditions may be linked and how if left untreated, sleep apnea negatively impacts treatment for AF, is described by the Heart Rhythm Society:
“The heart experiences mechanical stresses and chemical changes each time a person with sleep apnea is startled awake by lack of oxygen, and that may contribute to the development of AF.
In addition, studies suggest that untreated sleep apnea impairs the ability to control AF because it reduces the effectiveness of certain AF treatments.
For example, people with both AF and sleep apnea may not respond as well to medications to control the heart rate as AF patients without sleep apnea. Patients with sleep apnea are also more likely to have AF recurrences after a cardioversion or catheter ablation compared to AF patients without sleep apnea undergoing the same treatments.
Preventing sleep apnea makes AF treatments more effective—regardless of the treatment type (medication versus procedure). New research suggests that when both AF and sleep apnea are present, treating both is more likely to result in better health overall.”*
*Emphasis is mine.
Use of Home Testing for Sleep Apnea Grows
Recent estimates suggest that approximately one-third of all sleep apnea tests are now done using home sleep apnea testing kits instead of in-lab polysomnography testing which is supervised and performed overnight.
This trend is explained by the differences in both cost and accessibility/convenience. Sleep clinic testing is expensive – as much as $6,000 in out-of-pocket expenses. It may be difficult to obtain approval for reimbursement or not be covered.
In contrast, home kits are widely covered and may be recommended as the first-line diagnosis. The cost to the patient may be a co-payment as small as $10. Payment policies vary by payer so it’s always a good idea to check.
In addition to cost, there are accessibility issues: a patient has to go to the clinic and remain overnight for the testing. Many patients prefer home testing as it’s more convenient and they can relax in the privacy of their home and may be “more likely to reflect the actual disease manifestation.”
A Sleep Specialist Perspective
Omar Burschtin, M.D. is the Medical Director of the Mt. Sinai Sleep Program. He is a sleep specialist with a special interest in cardiovascular issues and describes his experience with both patients and physicians in Cardio Sleep Review-issue #2. Dr. Burschtin underscores that sleep apnea is “a common co-morbidity to AF.”
Dr. Burschtin believes that most cardiologists are “pretty aware” of the link between sleep apnea and AF. But, he says, they may want to treat their AF patient right away using ablation or cardioversion (electrical or chemical).
The timing problem
It may literally take months for a patient to be able to arrange a sleep clinic test and, unfortunately, patients don’t always show up. It may take another couple of weeks to get test results to the cardiologist.
The cardiologist may not want to delay cardiac treatment for up to five months until the patient can get a consultation, testing, scoring and therapy for sleep issues.
According to Dr. Burschtin,
“We know that managing AF patients with obstructive sleep apnea greatly improves outcomes and patient care. If they have sleep apnea and are treated, it reduces the chance of their having recurring arrhythmias after their treatment.”
Mt. Sinai, therefore, thought it would be a good idea for cardiologists to have the results of their patients’ sleep apnea tests before performing cardioversion or ablation.
Streamlining the sleep testing process
To address the timing issue, Mt. Sinai sets up a weekly clinic to help identify patients that would be appropriate candidates for home testing. The clinic’s staff tries to expedite insurance approvals for the testing. They also give the patients a home test – Itamar Medical’s WatchPAT – for sleep testing that night.
The WatchPAT is a medical grade home sleep apnea testing device. It is only available by prescription.
PAT™ – Peripheral Arterial Tonometry, is a non-invasive window into the Autonomic Nervous System at the finger. PAT signal is an accurate measure of the Pulsatile Arterial Volume at the finger and manifests vascular and microvascular activity which depends on sympathetic activity. This signal provides critical insight for classifying sleep/wake state and detecting sleep disordered breathing events. Because this technology uniquely uses finger-based physiology it avoids the complexity and discomfort associated with traditional airflow-based systems according to Itamar Medical.
This Mt. Sinai Sleep Clinic process is fast: patients or someone return the device the next day, sleep professionals review the results and their cardiologist receives a report the same day.
They find using the WatchPAT home test “allows them to be efficient” and “is easy for the patients and the results are reliable.” It helps meet their goal “to provide an immediate point-of-care and try to resolve a vacuum of the presence of sleep medicine in cardiac care.”
Notes from a Cardiologist with Sleep Apnea
Rick Pummil, M.D. has a unique perspective on the issue of sleep apnea and AF: he’s a cardiologist who also has severe obstructive sleep apnea and described his experience in an interview with Cardio Sleep Review-issue #2.
He agrees with the challenges outlined by Dr. Burschtin about scheduling and timing. Also, with regard to compliance, he says
“it’s not unusual for patients to come back to his office for follow-up visits months later only to learn they never went for their sleep lab test. Or if they did go, they never got the results.”
That’s where being able to use home testing devices like the WatchPAT has “changed his practice considerably and definitely for the better.” Patient compliance is much better, and they have immediate results.
If he suspects a patient may have sleep apnea, he sends them home with a test the same day they have an appointment with him. He gets the device back the next day, and if they have sleep apnea, they’ll get set up with a CPAP machine within 72 hours to begin treatment.
Home testing benefits both patients and their doctors, according to Dr. Pummil.
Total Sleep Solution Device
Given the links between sleep problems and heart disease, Itamar Medical has developed what it calls a “total sleep solution” for cardiovascular patients. I spoke to Gilad Glick, Itamar’s President and CEO, to learn more about their approach.
The WatchPAT was developed over a decade ago and uses PAT™ (Peripheral Arterial Tonometry), a non-invasive window into the Autonomic Nervous System at the finger. It’s an accurate measure of the signal that provides critical insight for classifying sleep/wake state and detecting sleep-disordered breathing events, explains Glick.
PAT is referenced in sleep apnea practice guidelines
The use of WatchPAT is now included in the practice guidelines of the American Academy of Sleep Medicine (page 490, bottom right paragraph). In a meta-analysis used to obtain FDA clearance, “the results showed there is an 89.7% correlation between our device and polysomnography,” according to Glick.
They also conducted a large study (n=455) with a typical mix of patients, who were referred to the Johns Hopkins Sleep Disorder Center described in WatchPAT™ Scoring Guidelines Leveraging Automated Scoring with Visual Oversight; John Hopkins Report 2018; Alan Schwartz, Hartmut Schneider; p1.
The project developed a streamlined approach for reviewing and editing the automated results from WatchPAT recordings; you can read about the scoring guidelines here.
The report authors concluded WatchPAT technology
“is unique among HSAT devices in its ability to render a fully automated, validated report, which compares extraordinarily well to gold standard polysomnography.”
A personal trial
At this point in my conversation with Glick, I put on the device he had brought to the interview. I was home-tested for sleep apnea with a different type of device a number of years ago. It required me to wear straps and wires and other such nonsense that completely interfered with my ability to fall asleep and stay asleep.
In contrast, the WatchPAT’s monitor strapped onto my wrist like at Watch and the sensor slipped over my index finger like a thimble. It was lightweight, comfortable, and seemed unlikely to interfere with sleep. There was nothing to turn on or off. It is a huge improvement in terms of patient comfort compared to what I had before.
An old device, a new approach
While the device is not new, Itamar’s current approach is. Originally, the company focused on marketing the device to sleep doctors.
However, after realizing the biggest unmet clinical need is for AF patients, they have a new mission focused on making sure every AF patient receives a sleep apnea workup and is treated before having an ablation. This is in line with AF guidelines that state that all AF patients should get a sleep apnea workup and if, diagnosed, receive treatment to prevent recurrence, according to Glick.
Glick summed up our conversation saying,
“It’s simple: for anyone suspected of having AF – by their primary care physician or cardiologist – all they have to do is hand the patient the WatchPAT to take home and they’ll be able to have an initial diagnosis for sleep apnea.
That’s easier and more convenient than being sent to a sleep lab for a polysomnography although that test may still be needed based on the initial diagnosis.”
A Population Management Tool
“Our goal is to improve sleep apnea management and its effective integration into cardiac patient care. So, we made the decision to address clinical practice related to sleep apnea and AF and not just focus on selling the WatchPAT to cardiologists,” states Glick. To do this, the company created the SleePathTM program to help cardiologists across their practice with a population management tool.
The fully-automated system links the data from the WatchPAT cloud to the Phillips CPAP cloud and tracks where patients are in the care continuum:
- Was the WatchPAT test positive?
- If yes, are they set up with a CPAP?
- Are they complying with CPAP or do they have residual apnea?
The data is loaded into the patient’s EHR. A follow-up questionnaire with cardiologists found positive feedback on the program explains Glick.
One desired outcome of Itamar’s new approach is to make sure that before someone has an ablation their cardiologist or electrophysiologist asks if they’ve been tested for sleep apnea.
If not, they will be handed a WatchPAT, go home and get their diagnosis. If positive, they can be treated for the sleep apnea first.
Glick notes that while the company is still collecting data and don’t have any yet that shows treating sleep apnea early in the disease progression reduces the need for ablation, there is data that shows the effectiveness of ablation and cardioversion is doubled although the latter procedure is performed less frequently.
There is data on treating apnea and ablation: NYU summarized post-ablation recurrence data that was studied with sleep apnea and without sleep apnea. The results for over 1,000 patients was that if AF patients with sleep apnea used CPAP, there was a 42% relative risk reduction in AF recurrence in patients with OSA.
And, finally, Glick notes that Itamar has created a physician portal CardioSleepSolutions with relevant literature, blogs from physician thought leaders and testimonials. The goal Glick says is to create awareness and education about the connection between sleep apnea, AF and AF treatment.
- Am J Epidemiol. 2013 May 1; 177(9): 1006–1014.
- Arq Bras Cardiol. 2014 Nov; 103(5): 368–374.
- J Atr Fibrillation 2016 Apr-May; 8(6): 1283
Many thanks to healthcare communication and public affairs consultant, Leslie Rose, for her expert assistance in the preparation of this story.