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According to Harvard Professor of Medicine, Dr. Peter Zimetbaum, “Using digital technology for personal health applications will soon become ubiquitous.” Smartwatches offer numerous possibilities: tracking the number of daily steps, helping you stay fit, checking your blood oxygen levels, stress, and even allowing you to record in just 30 seconds clinically relevant Electrocardiograms (ECG or EKG in short).
The Harvard Medical School estimates that more than 160 million people will soon use a watch or tracker to monitor their health and fitness. We are in the middle of a revolution in which personal healthcare will be a matter of being connected and quantified in real-time. In the world of smartwatches, not many of them are approved or cleared by the Food and Drug Administration (FDA). To obtain results you can rely on, it is key to choose the right wearable ECG. This article will present what the current best smartwatches to care for your heart health are.
What is an electrocardiogram (EKG/ECG)?
The electrocardiogram is one of the easiest and most informative clinical investigations in medicine. According to the American Heart Foundation, an electrocardiogram “measures the electrical activity of the heartbeat.” The heart will generate an electrical impulse that will flow from the atria to the ventricles to beat. By measuring the time it takes for the electrical signals to propagate and their intensity, cardiologists can define the heart’s health status.
The gold standard EKG uses 12 electrodes (12-lead electrodes) positioned around the heart and the torso. Without entering into too many details, only six of them will be on the torso (precordial), and the other six will be called limb electrodes.
An Electrocardiogram will not only provide valuable clinical data about heart rhythm diseases but will also inform the physician on:
- Blood flow within the heart,
- potential thickening of the walls of the cavities,
- electrolyte imbalances. Potassium and calcium are critical for the proper contractions of the cardiac muscle.
Smartwatches will, of course, not as relevant as a clinically validated 12-lead electrocardiogram. Still, they can be used as a very informative device that will unveil potential heart-health issues that will need to be addressed by cardiologists using more sophisticated instruments.
Instead of waiting for a chronic disease to progress silently, these smart devices have the potential to ring the alarm bell and potentially save your life. In cardiology, time is critical, and addressing issues promptly is the best way to stay healthy. Believe me on this. I suffered a heart attack when I was 39 years old, and I still suffer the consequences of not acting quickly enough.
Is a smartwatch with an ECG useful?
ECG smartwatches can not detect heart attacks or strokes but it doesn’t mean that they are not useful medical devices. Their main function is to detect arrhythmia.
Detection of Atrial Fibrillation (AFib)
Atrial Fibrillation is a type of heart arrhythmia expected to affect 12.1 million people in the USA by 2030. Every year, AFib leads to more than 450,000 hospitalizations and close to 160,000 deaths. Its prevalence increases with age, and high blood pressure has been associated as a contributing factor in 20 percent of the cases.
AFib is not a death sentence, though, and can be treated properly when diagnosed. ECG smartwatches offer an easy way to detect unknown conditions and check on the ongoing treatments’ efficacy.
Detection of rhythm abnormalities (bradycardia or tachycardia)
Bradycardia refers to a heart rate lower than 60 beats per minute. The amount of oxygenated blood pumped by the heart may not lead to proper body functions. Tachycardia is the opposite. The heart will beat too fast, more than 100 beats per minute. Both conditions can lead to fatigue, shortness of breath, and confusion.
Using an ECG smartwatch is an efficient way to detect heart rhythm anomalies early and to treat them. Being often transient, they can be difficult to diagnose. With the potential to analyze your heart rhythm anytime and anywhere, it becomes easier to reveal heart diseases and check on medications’ efficacy.
When in doubt, always consult your physician or cardiologist, who is the only one qualified to conduct clinical analyses and establish a diagnostic.
How does an ECG smartwatch work?
Contrary to clinical electrocardiograms that rely on detecting micro-currents at the skin’s surface, smartwatches ECG sensors use light beams and light-sensitive sensors. They detect the changes in the blood flowing through the wrist. This method of recording heart rate is known as photoplethysmography (PPG). Algorithms will process the signals and extract various information such as the ECG, Blood Pressure, or Heart Rate Variability.
In 2018, Dr. Castaneda et al. wrote a review of the potential of wearable photoplethysmography sensors in healthcare. They concluded that PPG could provide health-care providers with early detection of various cardiovascular diseases such as vascular aging. The key being to limit the effects of motion artifacts on the quality of acquired PPG signals.
The Apple Watch from Series 4 adds a one-lead electrode. Combine wrist photoplethysmography and electrical signals allow to improve the accuracy and reliability of the results.
The AliveCor KardiaBand also relies on a one-lead EKG. Dr. Kajakariar, from Box Hill Hospital, Australia, analyzed the clinical benefits of such a device compared with a full 12-lead EKG.
They concluded that the device offered moderate diagnostic accuracy. We somehow think that comparing devices that are so different introduced a negative bias in the study. This research somehow sheds light on the need to use devices that the regulatory authorities have approved.
Why does an FDA-approved/cleared device matter?
As part of its mission of protecting health in the U.S, the Food and Drug Administration is in charge of regulating and evaluating the potential health risk-benefit ratio of drugs and medical devices. Obtaining formal approval from the Agency is not an easy process as companies must follow a rigorous regulatory process and submit the results of the clinical tests they have conducted.
Most countries follow an equivalent pathway, with each of them having slight specificities. It explains why a smartwatch may be approved in Europe or Japan but not yet in the U.S. Regulatory matters take time and require patience from the manufacturers or pharmaceutical laboratories. Depending on the potential risk involved for human health, medical devices will fall into different categories.
FDA Clearance is a different level of acknowledgment. After submitting a “pre-market authorization” or 510(k) form, the company can get clearance for the device if it can prove that the performances are “equivalent” to a previously cleared product. The potential issue with cleared medical devices is that manufacturers can use old predicates.
In a perfect world, products should all be approved, meaning that specific clinical studies have been specifically conducted. The issue for health-related smartwatches is that these independent trials take time and are often not compatible with the products’ life cycle. Finally, the software can also be “regarded as a medical device.”
Pros and Cons of ECG smartwatches.
In 2018, the American Heart Foundation published an article stating that the use of new wearable technologies such as EKG watches could be beneficial for patients with heart diseases.
Dr. Ivor Benjamin, the President of the AHF, said that in his experience, “people often report symptoms that are absent during their medical visits. That’s why information is vital – information about a person’s daily lifestyle choices and their specific health data.” While the AHA does not endorse any ECG smartwatches, Dr. Benjamin added that they support any “advancements in the tools that can help fight heart disease, the No. 1 killer of Americans.”
According to a study published recently by Dr. Nino Isakadze, from the Johns Hopkins University School of Medicine, other benefits of ECG apps include:
- Screening for Atrial Fibrillations in a high-risk population,
- empowering the patients,
- evaluation of patients with palpitations,
- management of Atrial Fibrillations treatments and the impact of lifestyle modification.
Though challenges exist, smartwatches and fitness trackers should not be considered the ultimate tool to manage heart conditions. Some of the cons include:
- Price and accessibility, which are part of the so-called Social Determinant of Health,
- a false positive or false negative, which can lead to stress or a non-justified relief,
- lack of continuous monitoring,
- potential breach of privacy even though the devices are HIPAA compliant,
- clinical unreliability due to the use of PPG or single-lead EKG.
Best FDA-approved/cleared ECG smartwatches.
Below are the currently FDA-approved/cleared smartwatches offering the possibility to record an electrocardiogram and obtain a first analysis of the results. All of these devices should not be used by people under 22 years old.
Apple Watch Series 6
Samsung Galaxy Watch 3
Apple Watch Series 6
The Apple Watch Series 6 is undoubtedly one of the best smartwatches on the market, and not only when it comes to ECG. It combines everything from sleep tracking features to ECG monitoring and even detects falls. With a sleek design and a larger screen (44 mm), its only drawbacks may be linked to its battery life. But with so many to offer, the Apple Watch is a clear winner.
Apple Watch Series 6 (GPS)
Price when reviewed: $379.00
The latest TV ad for the Apple Watch focused on the possibility to take an electrocardiogram whenever or wherever you wanted. It is exactly what it is. The Apple Watch use both a 1-lead EKG and PPG. In less 30 seconds, the results will appear as:
- “Sinus Rhythm,” which means that heart rate is uniform and appears as normal,
- “Atrial Fibrillation,” which indicated that the heart beating pattern is not constant. Check with your physician.
- “Low or high heart rate,” which could signify that you are either experiencing bradycardia or tachycardia episodes. Check with your physician.
Apple validated the accuracy of the results in a study that included 600 subjects. The ECG app had a specificity of 99.6% for sinus rhythm detection and a sensitivity of 98.3% for AFib.
Samsung Galaxy Watch 3
With its rotating bezel, the Samsung Galaxy Watch3 is a smartwatch that doesn’t look like it. It will comfortably fit the boardroom and the gym. For Android fans, the choice is clear. The watch face comes in 2 sizes, 41mm or 45mm. Packed with fitness and health features, the performances are in line with a modern and premium smartwatch. Like the Apple watch, it will detect atrial fibrillation, tachycardia, and bradycardia. Its 340 mAh battery is rated for 2 full days.
Galaxy Watch 3 by Samsung
Price when reviewed: $329.00
The Samsung Galaxy Watch 3 offers the possibility to measure numerous health parameters, including blood oxygen saturation, blood pressure, and electrocardiogram. Atrial Fibrillation and other heart rhythm abnormalities are detected.
All health data are safely stored in the Samsung Health Monitor app that offers the possibility to send a pdf report to your health care provider. In the quantified world we live in, the Galaxy Watch 3 is also a device to consider, especially with its recent price drop, making it very affordable.
The Fitbit Sense is the latest model offered by Fitbit. It includes ECG readings and all you can expect from a fitness watch, but where it really shines is for stress measurement. Using an Electro Dermal Activity (EDA) sensor will detect your stress level and skin temperature. Some users have reported issues with the side inductive button that will activate unintentionally, but it offers all you can expect from the competitors when it comes to ECG.
Sense by Fitbit
Price when reviewed: $329.95
The ECG measurement requires putting two fingers on the Sense rim to complete the electrical circuit and waiting for 30 seconds. Although the Sense is perfectly capable of measuring body temperature and blood oxygen saturation, these measurements will be done at night. The results will be averaged out, making it difficult to get an instant measure, such as after a jog or workout session.
Unfortunately, the Fitbit Sense is not as responsive as other devices and is considered by most as a work in progress. With just a few hardware and software updates, the Sense may well show its full potential.
Also to consider
The KardiaMobile EKG Monitor by Avicor is technically not a smartwatch but works on the same one-lead electrocardiogram principles. Clinically validated and compatible with iOS and Android, it detects Atrial Fibrillation, bradycardia, and tachycardia. The results are displayed directly in the companion app. It only takes 30 seconds to record an FDA cleared electrocardiogram. This small and easy-to-carry device is a great alternative for those who want to benefit from heart rate monitoring without investing or wearing a smartwatch. To be noted that Avicor also offers a 6-lead device which could be a game-changer for portable ECG.
KardiaMobile by Avicor
Price when reviewed: $79.00