The role of artificial intelligence (AI) in our life is advancing rapidly and is making strides in the early detection of diseases. The consumer market is composed of wearable health devices that enables continuous ambulatory monitoring of vital signs during daily life (at rest or physical activity), or in a clinical environment with the advantage of minimizing interference with normal human activities1. These devices can record a wide spectrum of vital signs, including: heart rate and rhythm, blood pressure, respiratory rate, blood oxygen saturation, blood glucose, skin perspiration, body temperature, in addition to motion evaluation. However, there is a lot of controversies whether these health devices are reliable and secure tools for early detection of arrhythmia in the general population2.
Atrial fibrillation (afib) is the most common arrhythmia currently affecting over 5 million individuals in the US and it’s expected to reach almost 15 million people by 2050. Afib is associated with an increased risk of stroke, heart failure, mortality, and represents a growing economic burden3. Afib represents a diagnostic challenge, it is often asymptomatic and is often diagnosed when a stroke occurs. Afib represents also a long term challenge and often involves hospitalization for cardioversion, cardiac ablation, trans-esophageal echo, anti-arrhythmic treatment, and permanent pacemaker placement. However, if afib is detected, the risk of stroke can be reduced by 75% with proper medical management and treatment3.
Physicians need fast and accurate technologies to detect cardiac events and assess the efficacy of treatment. A reliable, convenient and cost-effective tool for non-invasive afib detection is desirable. Several studies assessed the efficacy and feasibility of wearable technologies in detecting arrhythmias. The Cleveland Clinic conducted a clinical research where 50 healthy volunteers were enrolled. They tested 5 different wearable heart rate monitors including: (Apple Watch, Garmin Forerunner, TomTom Spark Cardio, and a chest monitor) across different types and intensities of exercises (treadmill, stationary bike and elliptical). The study found that the chest strap monitor was the most accurate in tracking the heart rate across different types and intensities of exercises4.
Apple and Stanford’s Apple Heart Study enrolled more than 419,297 Apple Watch and iPhone owners. Among these users, 2,161 (roughly 0.5%) received a notification of an irregular pulse. Of those who received the notifications, only about 450 participants scheduled a telemedicine consultation and returned a BioTelemetry ECG monitoring patch. When the Apple Watch notification and ECG patch were compared simultaneously, researchers found 71% positive predictive value, and about 84% of the cases were experiencing Afib at the time of the alert. Additionally, 34% of participants whose initial notification prompted an ECG patch delivery were later diagnosed with Afib. This finding shows that Apple watch detected afib in about one-third of the cases which is “good” for a screening tool considering the “intermittent nature of afib and that it may not occur for a whole week” says Dr. Christopher Granger, a professor of medicine at Duke University who participated on the steering committee for the Apple Heart study5.
These studies are observational studies and are not outcome-driven. They are not randomized and are not placebo-controlled. There are potentials for false negatives, where the Apple watch fails to detect the afib and false-positive where it detects arrhythmia that does not exist. Unfortunately, patients who are false negative don’t consult the physician about their symptoms of palpitations and shortness of breath since it provides false security. While patients with false-positive are sent unnecessarily to the clinic that could lead to further unnecessary tests and anxiety for the patient.
Is the Apple Watch ready to be used as a default screening tool to monitor the heart rate and rhythm in the general population and by physicians with patients with or at high risk for Afib is still unclear and warrant further studies. In conclusion, physicians should be cautious when using data from consumer devices to treat and diagnose patients.
The views, opinions and positions expressed within this blog are those of the author(s) alone and do not represent those of the American Heart Association. The accuracy, completeness and validity of any statements made within this article are not guaranteed. We accept no liability for any errors, omissions or representations. The copyright of this content belongs to the author and any liability with regards to infringement of intellectual property rights remains with them. The Early Career Voice blog is not intended to provide medical advice or treatment. Only your healthcare provider can provide that. The American Heart Association recommends that you consult your healthcare provider regarding your personal health matters. If you think you are having a heart attack, stroke or another emergency, please call 911 immediately.
- Cheung, Christopher C., Krahn, Andrew D., Andrade, Jason G. The Emerging Role of Wearable Technologies in Detection of Arrhythmia. Canadian Journal of Cardiology. 2018;34(8):1083-1087. doi:10.1016/j.cjca.2018.05.003
- Dias D, Paulo Silva Cunha J. Wearable Health Devices-Vital Sign Monitoring, Systems and Technologies. Sensors (Basel). 2018;18(8):2414. Published 2018 Jul 25. doi:10.3390/s18082414
- Chugh, S., Sumeet, Havmoeller, J., Rasmus, Narayanan, F., Kumar, et al. Worldwide Epidemiology of Atrial Fibrillation: A Global Burden of Disease 2010 Study. Circulation. 2014;129(8):837-847. doi:10.1161/CIRCULATIONAHA.113.005119
- Wrist-Worn Heart Rate Monitors Less Accurate Than Standard Chest Strap. Medical Design Technology. http://search.proquest.com/docview/1875621494/. Published March 9, 2017.
- Turakhia, Mintu P., Desai, Manisha, Hedlin, Haley, et al. Rationale and design of a large-scale, app-based study to identify cardiac arrhythmias using a smartwatch: The Apple Heart Study. American Heart Journal. 2019;207:66-75. doi:10.1016/j.ahj.2018.09.002