Cardiac arrhythmias in obstructive sleep apnoea (CAOS)
Research type
Research Study
Full title
Cardiac arrhythmias in obstructive sleep apnoea (CAOS)
IRAS ID
291042
Contact name
Sriram Iyer
Contact email
Sponsor organisation
Sheffield Teaching Hospitals NHS Foundation Trust
Clinicaltrials.gov Identifier
STH21479, STH R&D ref number
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
Research summary
Obstructive Sleep apnoea (OSA) is a condition where the airway closes intermittently when patients fall asleep leading to pauses in breathing (apnoeas) and disturbed night-time sleep. This leads to sleepiness during the day but also increases night-time heart rate and blood pressure. It is closely related to being overweight in most patients and therefore patients with OSA can also have other obesity related conditions such as diabetes and heart problems. OSA is normally detected by a single overnight sleep study.It is now becoming evident that heart rhythm problems such as atrial fibrillation (AF) are more common in people with OSA but the mechanisms underpinning this relationship are poorly understood. In addition, the severity of sleep apnoea and quality of sleep can vary from night to night and it logically follows that heart rhythm problems can be affected by poor sleep quality or OSA severity. Therefore, we would like to assess sleep quality, sleep apnoea severity and heart rhythm over a number of nights in the patients’ own home. We plan to recruit 100 patients with sleep apnoea from Sheffield Teaching Hospitals (lead) and Liverpool University Hospital Foundation Trust. Each patient will be monitored with heart, oxygen, sleep and activity monitors at home over two weeks. The patient will also keep a sleep diary.
The results will hopefully highlight certain groups of patients with sleep issues who are at increased risk of cardiac arrhythmias and form the basis for a future larger study.
Summary of results
Cardiac Arrhythmogenesis in Obstructive Sleep Apnoea (CAOS) study:Multi-centre prospective observational study conducted by specialist sleep centres in Sheffield & Liverpool
Study funded by Bristol Myers-Squibb (BMS) as part of the BMS-Pfizer Alliance
Primary recruiting site and main sponsor: Sheffield Teaching Hospitals NHS Foundation Trust
Recruitment took place between Oct 2021 - Nov 2023
Background: Obstructive Sleep apnoea (OSA) is a condition where the airway closes intermittently when patients fall asleep leading to pauses in breathing (apnoeas) and disturbed night-time sleep. This leads to sleepiness during the day but also increases night-time heart rate and blood pressure. It is closely related to being overweight in most patients and therefore patients with OSA can also have other obesity related conditions such as diabetes and heart problems. OSA is normally diagnosed by a single overnight sleep study.
It is now becoming evident that heart rhythm problems are common in patients with sleep disorders, particularly sleep apnoea. The converse is also true i.e. people with heart rhythm problems more frequently have sleep apnoea. The reasons for this are not fully understood but it is recognised that sleep apnoea puts undue stress on the heart through a variety of mechanisms which increases the risk of arrhythmias.
We therefore wanted to study this group of patients in more detail by monitoring intensely various aspects of their sleep, activity and heart rhythm.Participants: These were patients referred to a specialist sleep centre with a strong suspicion of sleep apnoea based on their clinical history, demographics and other associated medical conditions. We excluded anyone with a previous history of cardiac problems including arrhythmias, pacemaker insertion , people with other sleep disorders, professional drivers and pregnant women.
Main questions:
1. What is the prevalence of heart rhythm problems in patients with OSA?
2. Are there specific groups of patients who are more susceptible?Study protocol:
Participants were consented to being monitored continuously at home over 2 weeks. During this period, they completed the following tests:
1. Continuous heart rhythm monitoring over 2 weeks via an ECG patch placed on their skin.
2. 3 separate overnight home sleep studies on days 1, 6 and 11 of the study.
3. An activity watch to map their physical activity and sleep patterns continuously over 2 weeks.
4. A clinical history, ECG and blood tests at baseline.Results: 104 participants were recruited into the study across both centres (Sheffield 79, Liverpool 25). There were 65 males and 39 females with an average age of 55 years.
86% of participants had sleep apnoea (OSA) with 27% mild, 23% moderate and 36% severe.
78% had evidence of cardiac arrhythmias. This group had OSA that was worse and also spent more of the night at lower oxygen levels (Time spent at SaO2<90%, T90).
Those with a worse T90 score seem to have a higher baseline heart rate and increased arrhythmia severity.Insights from this study:
It is clear from this study that abnormal cardiac rhythms are much more common in this group of patients with OSA than in the general population.
Preliminary results indicate that it is the average night-time oxygen level (T90) that dictates the risk of cardiac arrhythmias rather than the traditional severity scale (called Apnoea-Hypopnoea Index, AHI). This could have important implications on how we risk stratify and counsel patients when they have their sleep study.Further analysis:
More in-depth analysis of the low oxygen (hypoxic) burden is being undertaken in collaboration with colleagues from Harvard University to further strengthen the significance of the preliminary findings.
In addition, there are huge amounts of continuous multiple night data hat have not yet been analysed including data from the activity watch. The home sleep study data needs to be analysed simultaneously with the cardiac monitoring data. This requires computing power that can only be made possible by the use of AI.
Once this is complete, we hope to identify a group of particularly vulnerable patients who are at increased risk and follow them prospectively with or without the use of protective cardiac medications as part of an intervention study.
REC name
London - Bromley Research Ethics Committee
REC reference
21/LO/0582
Date of REC Opinion
1 Sep 2021
REC opinion
Favourable Opinion