Smartwatches have quickly evolved from simple fitness trackers to advanced health devices with features like integrated electrocardiograms (ECG). These innovations have sparked great interest, as ECG-enabled smartwatches offer convenient, everyday heart health monitoring and the ability to detect arrhythmias such as atrial fibrillation (AFib).
While these technologies are promising, it is important to understand the key differences between ECG measurements from a smartwatch and those in a clinical setting. In this article, we will explore these differences, assess the reliability of ECG smartwatches, and determine whether they truly represent a breakthrough in health monitoring.
| Also read: | Which Smartwatch is Recommended for Heart Patients | Blood Pressure Monitors | Heart Rate Monitor Watches |
What is an ECG, and how does it work in clinical practice?
An electrocardiogram (ECG) is a medical test that measures the electrical activity of the heart to detect irregularities. In clinical practice, multiple electrodes are attached to the skin, typically on the chest, arms, and legs. These electrodes capture electrical signals from different areas of the heart and provide detailed data that is analyzed by a doctor to diagnose arrhythmias, heart attacks, and other heart problems.
What problems can an ECG detect?
A clinical ECG provides detailed information about the rhythm, structure, and function of the heart. It is used to diagnose and monitor a variety of heart conditions, including:
- Arrhythmias: Irregular heart rhythms, such as atrial fibrillation (AFib), ventricular tachycardia, or bradycardia, can be detected by observing the electrical patterns of the heart.
- Heart Attacks (Myocardial Infarction): An ECG can reveal signs of a current or past heart attack by identifying changes in the heart's electrical activity.
- Coronary Artery Disease (CAD): ECGs can detect reduced blood flow to the heart muscle, indicating the presence of CAD, which untreated could lead to a heart attack.
- Heart Enlargement (Hypertrophy): Conditions like left ventricular hypertrophy can be detected by analyzing electrical signals indicating that the heart muscle is thicker than normal.
- Electrolyte Imbalances: Changes in ECG patterns can indicate abnormal electrolyte levels (such as potassium or calcium), which can affect heart function.
A 12-lead ECG, commonly used in medical settings, provides a comprehensive view of the heart's electrical activity from different angles, enabling a more accurate diagnosis of these conditions.
How do Smartwatches with ECG Function Work?
Smartwatches with ECG functionality, often referred to as ECG watches, provide a simplified version of a traditional ECG by using built-in sensors to measure the heart's electrical signals. Typically, these devices use a single-lead ECG system, where the user must touch a sensor on the watch (like the crown) with a finger from the other hand. This closes the circuit, allowing the smartwatch to record heart activity over a short period, usually around 30 seconds. While this can provide a quick snapshot of the heart rhythm, it is important to understand that not all smartwatches with heart monitoring functions are considered true ECG watches.
Are All Watches that Measure QT Intervals ECG Watches?
Some smartwatches claim to measure QT intervals, heart rate, or blood pressure, but these should not be confused with certified ECG watches. True ECG watches undergo extensive testing and approval processes to ensure their accuracy, safety, and reliability in detecting heart conditions like atrial fibrillation. Regulatory bodies such as the FDA in the U.S. or the CE mark in Europe set stringent standards that these devices must meet to be considered legitimate medical tools.
Limitations of Smartwatches with ECG Function
While some smartwatches with heart rate monitors and QT interval measurement, such as certain models from Kardena, Apple Watch, or Samsung Galaxy Watch, are designed to potentially detect certain arrhythmias like atrial fibrillation, it is important to understand their limitations:
- Single-Lead ECG vs. 12-Lead ECG: Unlike a comprehensive 12-lead ECG performed in a clinical setting, smartwatches provide only a single-lead ECG. This offers a very limited view of the heart's electrical activity and may not capture all types of irregularities. Therefore, they may be useful for detecting certain conditions, but should not be relied upon for a complete diagnosis.
- False Positives and False Negatives: The data from ECG smartwatches can sometimes lead to false positives (indicating a problem when none exists) or false negatives (failing to detect an existing issue). This can result in unnecessary worry or, conversely, a false sense of security.
- Not a Substitute for Professional Diagnosis: Smartwatches with ECG functionality should be viewed as complementary tools that can provide early warnings or assist in monitoring existing conditions. However, they do not replace professional medical examinations or diagnoses. Users should always consult a doctor or specialist if they have concerns about their heart health.
ECG Watches Are Officially Tested and Approved
Many devices that measure heart rate, blood pressure, or QT intervals can offer valuable insights into overall well-being, but they are not a substitute for medically certified ECG watches. Buyers should be aware that such devices, without proper testing and certifications, may not provide reliable or clinically meaningful ECG measurements. When choosing an ECG smartwatch, it is important to look for those that have undergone rigorous clinical validation and are approved by relevant health authorities to ensure that the data provided is accurate and trustworthy.
Benefits of Smartwatches as Early Warning Systems
Despite their limitations, ECG-enabled smartwatches can offer valuable benefits, particularly for users who are at risk for certain heart diseases or need to monitor their heart rhythm regularly. They allow for quick and convenient checks at home or on the go and provide data that can be shared for further analysis with a doctor.
- Monitoring Atrial Fibrillation (AFib): Some studies suggest that ECG smartwatches can help detect episodes of atrial fibrillation – a common but potentially serious heart rhythm issue that can increase the risk of stroke. However, it is crucial that users consult a doctor for confirmation and proper treatment.
- User-Friendly and Accessible: The ability to use a wearable and user-friendly device to check heart rhythm can empower users to take a more active role in health monitoring, always under professional guidance.
The Role of ECG Watches in Health Monitoring
Smartwatches with ECG functionality offer a promising tool for personal health monitoring, but they also have inherent limitations that users should be aware of. They provide a useful and accessible way to keep track of potential heart rhythm issues like atrial fibrillation. However, they do not replace professional, multi-lead ECG exams conducted in clinical environments. It is important that users view these devices as a supplement to regular medical care, to make informed decisions about their heart health in consultation with a doctor.
