The purpose of this 4-in-1 observational study is to test the performance of artificial intelligences (AIs) in distinguishing irregularly irregular heart rhythm called atrial fibrillation (AF) from normal heart rhythm using physiological signals collected by smartphones' built-in hardware and/or external accessories.

Participants will:

• Have their weight, height, resting heart rate and blood pressures measured
• Have 12-lead electrocardiogram (ECG) of their heart electrical activities recorded
• Have their heart sounds and 1-lead ECG recorded from their chest, and optical-based blood flow data (photoplethysmography or PPG) and 1-lead ECG recorded from their fingers using smartphones' built-in microphone, camera, and/or external accessories
• Optionally have their optical-based blood flow data recorded from their face using smartphones' built-in camera (remote PPG or rPPG).

The researchers will also create a database containing the physiological signals collected in this study along with the participants' medically relevant information to help train and test future AIs for medical applications.

4 observational studies have been combined into 1 observational study to share the same pool of participants. These 4 studies are designated as AUSC-AF, ECG-AF, AUSC+ECG-AF, and rPPG-AF corresponding to the signal modality/modalities used for AF detection (see outcome measures) and designated as AUSC/ECG/rPPG-AF when combined as 1 study.

Inclusion Criteria:

• Age: ≥22 years (adult)
• Patients who have one of the following:
• Permanent atrial fibrillation, or
• Long-standing persistent atrial fibrillation (12 months or longer), or
• Confirmed 12-lead ECG diagnosis for persistent atrial fibrillation (> 7 days) or sinus rhythm within 12 months at the time of their normal attendance at the hospital

Exclusion Criteria:

Any of the following:

• Implanted active medical devices in the torso, such as pacemakers and defibrillators
• Patients without atrial fibrillation who have another arrhythmia
• Completely missing one or more limbs, or missing any hand
• Disability in using their hands or arms
• Lack of both index fingers, or all fingers in any hand
• Both index fingers with any of the following characteristics:
• Tattooed/inked
• Reduced blood flow in the fingertip (e.g. perniosis or callus formation)

Hospital cardiology patients