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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Self-reported daytime sleepiness and sleep-disordered breathing in patients with Atrial Fibrillation
Scientific title
Self-reported daytime sleepiness and sleep-disordered breathing in patients with Atrial Fibrillation
Secondary ID [1] 296053 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Snooze AF
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Atrial Fibrillation
310376 0
Sleep-Disordered Breathing 310377 0
Condition category
Condition code
Cardiovascular 309097 309097 0 0
Other cardiovascular diseases
Respiratory 309098 309098 0 0
Sleep apnoea

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Patients with a atrial fibrillation, a common heart rhythm abnormality, are often referred for formal sleep studies (polysomnography) to assess for the presence and severity of sleep-disordered breathing. Sleep-disordered breathing, of which sleep apnoea is an important subtype, is a known risk factor for developing atrial fibrillation and its treatment can improve the likelihood of maintaining normal sinus rhythm following atrial fibrillation treatment. One of the main clinical consequences of sleep-disordered breathing is excessive daytime sleepiness which can be assessed using questionnaires. The polysomnography tests are usually performed overnight in a specialised sleep centre and are reported by a qualified sleep technician and a respiratory physician. The duration of observation spans over the recruitment period which is from January 2012 to March 2017.
The electronic health records of the study patients will be examined and the following parameters (already present health records) retrieved for analysis: medical background (clinical history), antrhopometric data (weight, height and BMI), medication history, echocardiographic data, clinical questionnaires (AF severity questionnaires and sleepiness questionnaires) as well as the formal polysomnography reports. These data are already present in electronic format in medical records and will be accessed to retrieve the relevant information for the study once approved.
Intervention code [1] 312888 0
Diagnosis / Prognosis
Comparator / control treatment
Formal polysomnography tests are assessed by a respiratory physician and a diagnosis of the presence and severity of sleep-disordered breathing is made. Patients with sleep-disordered breathing will function as the main study group, and those without will be the controls.
The clinical data will be retrieved from the Centre for Heart Rhythm Disorders and Royal Adelaide Hospital over the period of the study, January 2012 to March 2017.
Control group

Primary outcome [1] 308070 0
Diagnosis of sleep-disordered breathing as quantified by polosymnography
Timepoint [1] 308070 0
At time of polysomnography
Secondary outcome [1] 353871 0
Excessive Daytime Sleepiness (quantified using the Epworth Sleepiness Scale)
Timepoint [1] 353871 0
At time of undergoing polysomnography

Key inclusion criteria
• Age equal to or greater than 18 years
• Diagnosed with paroxysmal or persistent atrial fibrillation (according to the 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation.
• Referred to, and completed, a formal overnight polysomnography (PSG)
• Completed a contemporaneous Epworth Sleepiness Scale questionnaire
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Insufficient polysomnography data (less than 4 hours of sleep study or absence of measured apnoea-hypopnoea index reporting).
• Incomplete Epworth Sleepiness Scale score
• Pregnancy

Study design
Defined population
Statistical methods / analysis
Clinical characteristics and relevant data from polysomnography, including apnoea-hypopnoea index (AHI), in addition to Epworth Sleepiness Scale (ESS) will be retrieved from Electronic Medical Reports (EMRs). Statistical analysis will be performed using SPSS statistical software for Windows (Version 24; IBM corp.). Following the reporting of descriptive statistics, the correlation between ESS and AHI will be tested using the Pearson correlation coefficient testing. The utility of ESS to predict SDB will be tested using the receiver-operating-characteristic (ROC) analysis and presented as area-under-the-curve (AUC). A binary logistic regression model that would utilise the available clinical features will be constructed to try and identify patients with significant sleep-disordered breathing.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 12388 0
The Royal Adelaide Hospital - Adelaide
Recruitment postcode(s) [1] 24653 0
5000 - Adelaide

Funding & Sponsors
Funding source category [1] 300641 0
Name [1] 300641 0
University of Adelaide
Address [1] 300641 0
Centre for Heart Rhythm Disorders - part of the University of Adelaide and the Royal Adelaide Hospital
Cardiology 4G751-769
Royal Adelaide Hospital
Port Rd, SA 5000
Country [1] 300641 0
Primary sponsor type
Professor Prashanthan Sanders
Director, Centre for Heart Rhythm Disorders
NHMRC Practitioner Fellow,
Knapman-NHF Chair of Cardiology Research,
University of Adelaide | SAHMRI
Director, Cardiac Electrophysiology & Pacing,
Royal Adelaide Hospital
Port Road
SA 5000
Secondary sponsor category [1] 300777 0
Name [1] 300777 0
Address [1] 300777 0
Country [1] 300777 0

Ethics approval
Ethics application status
Ethics committee name [1] 301430 0
Central Adelaide Local Health Network (CALHN) Research Ethics Committee
Ethics committee address [1] 301430 0
L3, Roma Mitchell House, North Terrace, Adelaide – Postal Details: RAH Clinical Trial Centre, Wayfinder 3D460.02, Level 3, Royal Adelaide Hospital, Port Road, ADELAIDE SA 5000
Ethics committee country [1] 301430 0
Date submitted for ethics approval [1] 301430 0
Approval date [1] 301430 0
Ethics approval number [1] 301430 0

Brief summary
Sleep-disordered breathing (SDB) is common in patients with atrial fibrillation (AF) and is associated with poor clinical outcomes. International AF management guidelines advocate for the interrogation for clinical signs of SDB when addressing AF risk factors given the important interplay between SDB and AF. Excessive daytime sleepiness is an important clinical consequence of SDB and its presence can be a key consideration in patient selection for SDB investigation and management. However, patients with cardiovascular disease report low levels of daytime sleepiness. Therefore, relying on self-reported daytime sleepiness in patient selection for diagnosis and management can potentially result in a significant proportion of patients not being identified with SDB or provided appropriate management opportunities.
We hypothesise that in patients with atrial fibrillation, excessive daytime sleepiness is low and that self-reported sleepiness correlates poorly with the presence or degree of SDB. We aim to test this hypothesis by studying patients with AF who have undergone overnight sleep studies. We will assess the self-reported sleepiness and its correlation to the presence and degree of SDB. We will test the utility of the Epworth Sleepiness Scale, a widely used tool to quantify daytime sleepiness, to predict the presence of SDB. Further, we aim to characterise clinical features that can help identify patients with significant SDB, and assess the potential impact this would have on AF management.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 86966 0
Prof Prashanthan Sanders
Address 86966 0
Royal Adelaide Hospital
Cardiology 4G751-769
The University of Adelaide
Port Rd, SA 5000
Country 86966 0
Phone 86966 0
+61 8 8313 9000
Fax 86966 0
Email 86966 0
Contact person for public queries
Name 86967 0
Dr Kadhim Kadhim
Address 86967 0
Royal Adelaide Hospital
Cardiology 4G751-769
The University of Adelaide
Port Rd, SA 5000
Country 86967 0
Phone 86967 0
+61 8 8313 9000
Fax 86967 0
Email 86967 0
Contact person for scientific queries
Name 86968 0
Dr Kadhim Kadhim
Address 86968 0
Royal Adelaide Hospital
Cardiology 4G751-769
The University of Adelaide
Port Rd, SA 5000
Country 86968 0
Phone 86968 0
+61 8 8313 9000
Fax 86968 0
Email 86968 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
Study protocol
Ethical approval
Summary results
No Results