--- Background and study aim

Atrial fibrillation (AF) is an irregular heart rhythm which causes a five-fold increase in the risk of stroke. Approximately one in ten people aged over 70 have AF. If AF is recognised then the risk of stroke can be reduced by taking tablets regularly. AF can be difficult to recognise as it can occur without symptoms and only intermittently. Consequently, AF is not recognised in many people, meaning they live with an increased risk of stroke. Therefore, it is important to find ways to identify AF more reliably.

Recently, wearable devices have been developed which could be useful for identifying AF. Several devices can monitor heart activity in daily life, including wristbands, smart watches and chest patch monitors. The aim of this study is to assess the acceptability and performance of wearables for use in AF screening in older adults.

The primary objective is to determine the feasibility of measuring inter-beat-intervals using a wristband. The secondary objectives are:

(i) to determine the acceptability of wearables; (ii) to determine the acceptability of the screening approach; (iii) to assess the performance of wearables for acquiring signals; (iv) to assess the performance of signal processing algorithms; and (v) to assess the performance of wearables for AF screening.

--- Who can participate?

Selected people who have previously participated in the SAFER Programme can participate in this study. The Investigators will invite previous SAFER Programme participants to also participate in this study, aiming to enrol 65 without AF, and 65 with AF.

--- What does the study involve?

Participants will be asked to wear three devices for seven days: Two wristbands (like watches), and one chest patch (like a plaster). These devices will collect measurements of their heart's activity. The Investigators will also ask participants to tell them how they found wearing the devices by completing a questionnaire. The Investigators will compare how participants found wearing each device, and how accurately each device identifies AF.

--- What are the possible benefits and risks of participating?

There will be no direct benefit to participants, although this research is intended to benefit future patients like them. Some participants may experience irritation or redness whilst wearing a chest patch - participants will be advised that if this occurs then they should remove it straightaway.

--- Where is the study run from?

The University of Cambridge.

--- Study procedures

Participants will be asked to:

1. Consent: Participants will be asked to confirm their consent to take part by posting the enclosed consent form to the Investigators in a prepaid envelope.
2. Device delivery: The Investigators will send participants the devices, a detailed instruction leaflet, and a questionnaire.
3. Training: The Investigators will explain to participants how to wear and use the devices over the telephone, referring to the instruction leaflet.
4. Wear the devices: Participants will be asked to wear the devices for seven days, going about their daily life as normal. The devices are waterproof. If a participant has chest hair then they will need to shave a small area for the chest-patch to stick to. The Investigators will ask participants to use the watch four times each day to record heart activity for 30 seconds. Participants will be asked to plug in a small hub which will send information from the devices. The Investigators will telephone participants during the study to check for any problems.
5. Questionnaire: Participants will be asked to complete a questionnaire on the devices after wearing them.
6. Return devices: At the end, the Investigators will telephone participants and arrange a courier to pick up the devices and questionnaire from their home (which the Investigators will arrange and pay for).

Participants will be given an instruction leaflet with further details of each step.

Inclusion Criteria:

• AF screening successfully completed during the SAFER Programme
• Aged 65 years or over
• Lives in private accommodation
• Willing and able to give informed consent

Exclusion Criteria:

• Regularly sleeps on front
• Has a chest wound
• Previous reaction to, or known allergy to ECG electrodes or silicone
• Receiving palliative care

Potential participants for the study will be identified from amongst previous participants of the SAFER Programme (ISRCTN 16939438 and ISRCTN 72104369).

The following data from individual participants will be anonymised and shared:

• Participant characteristics
• Quantitative questionnaire data (providing feedback on the wearable devices)
• Device data including physiological signals, physiological parameters, and technical parameters.

Data will be made available within 12 months of the study ending. It will made available indefinitely via an online repository.

None planned