A Guide to Wearable ECG Technology for Heart Rhythm Monitoring
Introduction – The Rise of Smart Devices in Heart Health
Smartwatches and wearable health technologies have rapidly become valuable tools for Australians managing long-term health conditions. For people living with atrial fibrillation, a common heart rhythm condition, these devices offer new opportunities to track symptoms, detect arrhythmias early, and share critical health data with their care team.
At Queensland Cardiovascular Group (QCG), our specialists are increasingly seeing patients who arrive with ECG recordings taken directly from their wristwatch. When used appropriately and supported by expert review, these devices can empower patients and accelerate diagnosis.
What is Atrial Fibrillation?
Atrial fibrillation (AF or AFib) is the most common heart rhythm disorder. It occurs when the electrical signals in the heart’s upper chambers (the atria) become disorganised, causing the atria to quiver instead of beating effectively.
This irregular activity leads to a heartbeat that can be fast, slow, or erratic. Even when episodes come and go, atrial fibrillation is typically a chronic, progressive condition that requires long-term monitoring and management.
What Happens to the Heart During Atrial Fibrillation?
In a healthy heart, electrical signals flow in a steady, rhythmic pattern. But during an atrial fibrillation episode, chaotic impulses in the atria override the usual rhythm. This causes the atria to lose their coordinated contraction, and the signals reaching the lower chambers (ventricles) become erratic.
As a result, a person with atrial fibrillation may feel palpitations, fatigue, breathlessness—or, in some cases, no symptoms at all.
Why Are ECGs Important in Diagnosing Atrial Fibrillation?
An electrocardiogram (ECG) is a non-invasive recording of the heart’s electrical activity. It’s the gold standard for diagnosing and monitoring atrial fibrillation. Cardiologists interpret the shape and timing of the ECG waveform to determine whether atrial fibrillation—or another arrhythmia—is present.
In clinical settings, a 12-lead ECG is used. This records the heart’s electrical signals from multiple angles using 12 electrodes placed across the chest, arms, and legs. It provides detailed information that helps identify the type and source of an abnormal rhythm.
However, these recordings only capture the heart’s activity at a single point in time, when the test is undertaken— for people with intermittent atrial fibrillation, it can be difficult to diagnose if they don’t have symptoms at the time.
Do Smartwatches Detect Atrial Fibrillation?
Yes—some modern smartwatches now include built-in ECG sensors that allow users to record a heart rhythm trace at home. These devices use software algorithms to analyse the recording and alert the user if signs of atrial fibrillation are detected.
This means that a smartwatch might be a person’s first source of an atrial fibrillation warning—especially in people who experience few or no symptoms.
How Do Wearable ECGs Differ from 12-Lead ECGs?
A smartwatch ECG uses a single electrode (usually built into the watch’s underside and crown) to capture a one-lead ECG trace. While it lacks the depth and precision of a 12-lead ECG, it can still identify irregular heart rhythms, including atrial fibrillation.
Advantages:
- Can be used instantly to record an ECG when symptoms occur
- Records tracings that can be shared with a doctor
- Useful in detecting episodes that occur outside clinic hours
Limitations:
- Less comprehensive than clinical ECGs
- Will not detect all heart conditions
- The quality of the tracing can be vulnerable to movement, interference or poor contact
What Are the Limitations of Smartwatch ECGs?
Although smartwatches are impressive tools, their ECG capabilities do have limitations when compared to clinical devices:
- Limited information: Because a wearable device is a single-lead ECG, it provides less information about the heart’s electrical activity than a 12-lead ECG. This means that certain heart conditions may not be detectable with a smartwatch ECG.
- Limited accuracy: Smartwatch ECGs use a single electrode sensor, which may not provide as accurate measurements as the multiple electrodes used in a 12-lead ECG. This means that the results of a smartwatch ECG may not be as reliable as those from a traditional ECG.
- Limitations in detecting cardiac conditions: Single-lead ECGs typically cannot detect certain cardiac conditions, such as a bundle branch block or a left ventricular hypertrophy.
- Interference: The signal detected by the single-lead ECG can be affected by noise, interference and artifact which can affect the quality of the ECG tracing.
- Dependence on correct positioning of the device: Smartwatch ECGs require the user to wear the device in the correct position to ensure accurate measurements.
- Not intended for diagnosis: The smartwatch ECG is not intended to diagnose, cure, mitigate, treat, or prevent any disease or medical condition and should not be used as a substitute for a traditional ECG or medical advice.
How Accurate Are the Algorithms Used within Smart Watches at Detecting Atrial Fibrillation?
Smart watches use algorithms to detect signs of atrial fibrillation from the ECG they record. Their sensitivity (true positive rate) and specificity (true negative rate) generally range from 70–90% in clinical trials.
However, accuracy varies depending on:
- The model and software version of the device
- The quality of the ECG signal
- The user’s posture, physiology, or movement during recording
- The heart rate—many algorithms struggle above 120 bpm
Importantly, even if the ECG trace is high-quality, the algorithm may still misinterpret it. That’s why cardiologist review remains essential.
Are Wearable ECGs Valued by Cardiologists?
Yes—when used appropriately, many cardiologists consider wearable ECGs to be extremely helpful.
Dr Robert Perel, Cardiac Electrophysiologist and Director at QCG, explains:
“Until recently, patients had no way of recording their heart rhythm when symptoms occurred. They would have testing done at their appointment, but we would have no data on the actual symptom episode. Now, people can capture that data on their own watch and then show this to their doctor. This has significantly improved our ability to diagnose atrial fibrillation accurately and quickly.”
Dr Perel emphasises that while devices can alert you to possible AF, the condition is complex and needs thorough evaluation. Smart watches may provide a “snapshot,” but clinical confirmation and follow-up testing are still critical. A Cardiac Electrophysiologist (a sub-specialised cardiologist in heart rhythm) may want to look at the ECGs from your device recorded while your symptoms are present to interpret information beyond the capacity of the current algorithms. They may also need to follow up with a 12-lead ECG and other tests for further information to inform your diagnosis and treatment options.
When Are Wearables Most Useful for Atrial Fibrillation?
Smart watches are especially useful when:
- Atrial fibrillation symptoms are intermittent and difficult to catch during a clinic visit.
- Patients want to monitor response to treatment (e.g. medications or ablation).
- There’s a need to correlate symptoms with heart rhythm.
Additionally, some users benefit from the broader health tracking features – such as sleep monitoring, guided breathing, or fitness metrics- that help manage overall heart health and stress levels.
Are There Downsides to Smart Watch Monitoring?
While self-monitoring technology is useful for some people to monitor their condition, for others, wearable devices and continual monitoring can actually become a source of stress and anxiety – and anxiety can potentially make their atrial fibrillation symptoms worse. Some people find themselves frequently checking the device, limiting their activities or worrying about what each reading might include.
Sometimes there also becomes too high a level of trust in wearable devices – inaccuracies can be introduced where the device doesn’t get a good reading due to poor contact or movement, and their technology is based on heart rates and single-lead ECGs, which are not as accurate as a full 12-lead ECG. At times, cardiologists have found that certain notifications are alarming patients when there wasn’t an actual problem – like a slow heart rate that was detected during a deep sleep, when this can be a completely normal pattern for some patients.
Here are some of the main downsides of using a smart watch ECG for some people:
- Health anxiety: Constant checking and over-interpretation of results
- False reassurance: Missed readings may lead users to ignore worsening symptoms
- Device dependency: Fear of exercising or socialising without the device on
- Information overload: Misinterpreting normal variations in heart rate or rhythm
Dr Perel advises that wearable ECGs are a tool—not a solution. If wearing one increases stress or confusion, then it may not be the right fit for that person.
Choosing the Right Device for Atrial Fibrillation Monitoring
As of 2025, several smart watches and portable ECG devices have been approved by Australia’s Therapeutic Goods Administration (TGA) for their ability to record a medical-grade ECG. A medical-grade ECG is critical if the information is to be trusted (although with the limitations explained above). Each of these options offers unique features—your choice will depend on your health needs, preferences, and lifestyle.
Note, please check current device information
Apple Watch Series 4 and Later
Apple’s ECG feature, introduced with the Series 4, has been TGA-approved since 2021. The latest models, including Series 10, offer advanced features like the AFib History tool, providing users with insights into their heart rhythm patterns over time. However, it’s important to note that the ECG app is not intended for users under 22 years of age or those previously diagnosed with AFib.
Samsung Galaxy Watch Series
Samsung’s Galaxy Watch series, starting from the Galaxy Watch 3, includes TGA-approved ECG functionality. The Galaxy Watch 5 and newer models feature the BioActive Sensor, which combines ECG, heart rate, and body composition measurements, offering comprehensive health monitoring.
Fitbit Sense Series and Charge 5
Fitbit’s Sense series and Charge 5 have received TGA approval for their ECG apps. These devices allow users to record ECG readings and assess them for signs of AFib. The integration with the Fitbit app provides a user-friendly interface for tracking heart health over time.
Google Pixel Watch Series
The Google Pixel Watch, leveraging Fitbit’s technology, includes an ECG app that has been TGA-approved. Users can record ECGs and receive notifications about irregular heart rhythms, aiding in the early detection of AFib.
Withings ScanWatch
Withings’ ScanWatch combines traditional analog watch design with advanced health features, including a TGA-approved ECG function. It continuously monitors heart rate and can detect AFib episodes, providing users with timely alerts.
AliveCor KardiaMobile Devices
AliveCor offers portable ECG devices like the KardiaMobile and KardiaMobile 6L, both TGA-approved. These devices connect to smartphones and provide single-lead or six-lead ECG recordings, which can be shared with healthcare providers for further analysis.
CardiacSense Medical Watch
CardiacSense’s medical watch is designed for continuous monitoring of vital signs, including ECG. TGA-approved, it offers long-term tracking suitable for both in-hospital and ambulatory settings, enhancing patient care through real-time data.
QardioCore Wearable ECG Monitor
QardioCore is a chest-worn device that provides continuous ECG monitoring without the need for wires or patches. TGA-approved, it streams medical-grade data to smartphones, facilitating proactive heart health management.
When selecting a wearable ECG device, it’s crucial to consider factors such as comfort, battery life, compatibility with other health apps, and the specific features that align with your health monitoring needs. Consulting with a healthcare professional can provide personalized recommendations based on your medical history and lifestyle.
So, Are These Devices Useful for People with Atrial Fibrillation?
For many Australians living with atrial fibrillation, TGA-approved smartwatches and portable ECG devices are a powerful tool for self-monitoring. QCG’s electrophysiologists report that these technologies are often instrumental in:
- Capturing real-time ECGs during symptoms
- Supporting earlier diagnosis and treatment planning
- Enabling meaningful discussions between patient and cardiologist
- Tracking response to interventions (e.g. medications, ablation)
Dr John Hayes, Director and Cardiac Electrophysiologist at QCG, shares:
“Many patients bring their watch readings to the consultation, or send them through beforehand. These recordings are often the missing puzzle piece we need to correlate symptoms with rhythm—and take decisive action.”
That said, your device is only one part of the picture. Wearables are most effective when used in partnership with an experienced cardiology team.
The Future of Wearables in Atrial Fibrillation Care
The growth in wearable HealthTech is opening new frontiers in how we detect and manage heart rhythm disorders:
- Big data studies (like the Apple Heart Study with over 400,000 participants) are shaping global understanding of atrial fibrillation.
- Machine learning and AI are improving rhythm detection algorithms.
- Increased accessibility of health data is empowering patients to be active partners in their care.
Dr Robert Perel of QCG explains:
“We’re just at the beginning. As more people wear smart devices and share their heart data, we’ll discover new patterns and interventions—potentially even preventing strokes or hospital admissions through earlier detection.”
From capturing “silent” atrial fibrillation to guiding public health insights, wearable ECGs represent a powerful shift toward personalised, real-time care.
Next Steps – Learn More or Get Help
If you’re considering a wearable ECG device or have already received alerts from your smart watch, it’s important to speak with a healthcare professional.
QCG’s team can help interpret your device data, confirm a diagnosis, and guide your treatment—whether you’re newly diagnosed or already managing atrial fibrillation.
Learn more:
Take action:
- Book an Appointment
- Contact Our Team
