Diagnostic Accuracy of WEARable TECHnology Single-lead ECG in Detecting Cardiac Arrhythmias

Atrial fibrillation (AF) is the most common arrhythmia (irregular heart rhythm), affecting 1-2 million people in the UK. AF significantly increases the risk of an AF-related stroke, heart failure and dementia. A significant proportion of people will have no symptoms, and they may only be found to have AF after suffering an AF-related stroke.

An electrocardiogram (ECG) uses sensors placed on the skin to record the heart's electrical activity. A 12-lead ECG uses 10 sensors and is the gold-standard (best available test) to detect any abnormal heart rhythm disturbances. Until recently, a 12-lead ECG showing an irregular heart rhythm was required to make a diagnosis of AF but as AF episodes are often short and unpredictable it may be missed. Therefore, a small device that continuously records heartbeat and heart rhythm could make the diagnosis of arrhythmias and AF much quicker and easier.

Accessories such as watches or rings - referred to as wearable devices - have extremely good sensors that measure pulse rate by detecting small changes in skin colour during each heartbeat and can perform a single-lead ECG. Algorithms built in the wearable devices can identify irregular heart rhythms, such as atrial fibrillation.

The purpose of this study is to test two new wearable devices - the Skylabs CART-I ring and the Apple Watch - in detecting abnormal heart rhythm recording and recording ECGs. The investigators plan to recruit 500 patients attending Cardiology Departments in several hospitals in the UK and will ask them to wear the Apple Watch and the CART-I and perform 12-lead ECG with each device (two in total). No extra follow-up visits are required. At the end of the study, the investigators will compare interpretation by two cardiologists of the wearable devices' ECGs and the 12-lead ECGs and look at their ability to automatically detect abnormal rhythms.