How wearable technologies can facilitate earlier atrial fibrillation detection


Atrial fibrillation is the most common form of heart rhythm abnormality, affecting around 2 million people in the UK. Dr Shouvik Haldar, consultant cardiologist and electrophysiologist at Royal Brompton and Harefield hospitals, explains how wearable technologies can help make earlier detection easier

What is atrial fibrillation?
Atrial fibrillation (AF) is a heart condition that causes an irregular and often abnormally fast heart rate, in some cases significantly higher than 100 beats per minute—a normal resting heart rate should be between 60 and 100 beats per minute. When the heart beats normally, its muscular walls contract to pump blood around the body and then relax again so the heart can fill with blood, but in AF, the top chambers of the heart (the atria) contract randomly and fast, causing electrical impulses to fire off in a disorganised way. When the atria twitch or quiver, this is known as fibrillation.

Symptoms of AF include heart palpitations, dizziness and shortness of breath. You may be aware of palpitations when your heart feels like it’s pounding or fluttering, for a few seconds or even a few minutes. An important factor to be aware of is that AF often goes undetected. Many people with AF experience no symptoms until the disease is in an advanced state, and a serious complication such as a stroke or heart failure results.

Why is diagnosis of AF difficult?
Symptoms can be intermittent in the early stages of the disease and even a 24-hour electrocardiogram (ECG) can miss the abnormality. Without expert diagnosis, people cannot get the right treatment and are at serious risk of having a stroke. This is because AF gives opportunity for the blood to pool and form into a clot, which cannot be properly pumped out of the heart. When a clot breaks away and causes a blockage, it results in a stroke—caused by blood supply to the brain being cut off—which can be debilitating or deadly. In fact, AF is the leading cause of stroke.

When it comes to AF, the exact cause is unknown, but it is more common in those with other heart conditions such as high blood pressure (hypertension), coronary artery disease, atherosclerosis, or a heart valve problem. It is also more common in people aged over 65. Today, research and increased understanding have enabled doctors to assess an individual’s risk of an AF-related stroke and prescribe a therapy that can reduce this risk significantly.

Wearable technologies are another big area of innovation that are facilitating early detection, especially at a time when the coronavirus pandemic is resulting in many people searching for alternative ways to monitor their health.

How can wearable technologies help?
Today, wearable technologies, which use sensors and smartphone applications, have made tracking our activity easier. They are also in growing demand for those who want to take control of their health, providing a quick, easy way to keep track of physical activity and heart rate. Outside of health and fitness, smartphones and wearable technologies such as ECG monitors and smartwatches are helping to combat the challenges of heart monitoring, in particular AF detection.

Potoplethysmography (PPG) technology, for instance, has emerged as a strong, non-invasive modality for continuous heart rate monitoring. The technology detects blood circulation changes using a light source and a photodetector at the surface of skin. Nowadays, most wearable devices on the market—including smartphones and smartwatches—have built-in PPG sensors, which many patients can make use of.

How do wearable devices work?
While there is a growing body of evidence pointing to the ability of PPG-based wearables in facilitating AF detection, it’s worth noting that wearables are not a substitute for medical devices prescribed by a clinician. Instead, they represent real-time connectivity and feedback, allowing patients to present clinicians with data which should be interpreted in context. When captured over time, this data can offer a more complete perspective of an individual’s health, bringing a new dimension to clinical monitoring, particularly in a non-clinical setting.

Most wearables come with a mobile app that collects and tracks data, helping users to understand what the data means and track it over time. Significant changes or repeating events may thus indicate a health problem. Overall, the collection of data over time helps clinicians understand what’s going on and determine the next best course of action, if any. However, it is important to appreciate that all devices have limitations and patients do need to know how to use them properly to get the best out of them.

When should I seek help?
The Covid-19 pandemic has accelerated an already growing market for fitness and wellness wearables. In many cases, they can be used as a supplementary tool to detect abnormalities in heart rate and rhythm, helping to prevent further complications such as stroke. If you are suffering from heart rhythm problems and wish to use a wearable, speak to your clinician first regarding the pros and cons of various devices to help you decide which is the best for you.

If you are using a wearable to monitor the problem, consultant cardiologist and electrophysiologist, Dr Shouvik Haldar at Harefield Hospital, can explain what to do with the information gathered from the device. To make an enquiry or book a video appointment email