Researchers wanted to know if a smartwatch app could detect atrial fibrillation in those with no prior history of the condition.
We use smartphone apps to keep track of our lives, from coffee dates to shopping lists. But, what about using apps to monitor our health? Can a smartwatch app detect atrial fibrillation?
That is exactly what researchers at Stanford University wanted to see. In a study published in The New England Journal of Medicine, researchers released an app to see if a smartwatch could detect atrial fibrillation in those with no prior history of the condition.
Atrial fibrillation, or abnormal heart rhythm, is a medical condition that affects six million Americans. If left undiagnosed, it doubles the risk of heart failure and quintuples the risk for stroke. Even if someone wears a heart monitor, a device that measures heart rhythm, they are typically worn for a short time period. Some may even require a procedure to implant the device into the user. With a limited monitoring period, it is possible that the fibrillations may be infrequent and missed during the time that the heart monitor is activated.
Smartwatches, on the other hand, can be worn unobtrusively and for longer time periods. Researchers used these smartwatch benefits to run a large, fully online trial to see if a smartwatch app can detect atrial fibrillation.
The app was available in the United States from November 29, 2017, to August 1, 2018. During that time period, 419,297 participants were recruited. Of those participants, 2,161 received a notification that they had an irregular heart rhythm. Those who received a notification were sent an electrocardiogram (ECG) patch in the mail. An ECG checks heart function by measuring the electrical signals in the heart. Participants were given the ECG patch to see if the smartwatch app notifications they received were actual atrial fibrillations.
The study had two major findings for those who received a notification:
- The ECG patch alone showed that 34% of participants had atrial fibrillation.
- When the ECG patch was worn, 84% of subsequent notifications on the app were confirmed to be atrial fibrillation by the ECG patch.
The first finding is clinically important because the ECG detected fibrillations that were quite long and uncomfortable, some even lasting more than an hour. Even if the ECG patch did not show atrial fibrillation, it could be that the fibrillations were infrequent and did not manifest when the ECG was worn.
The second finding shows that the app has a low incidence of false notifications—if the participant was notified, it was most likely because they had atrial fibrillation and not an artefact of the app. The app, however, could not detect short episodes of atrial fibrillation, so those episodes could have been missed.
Despite the study being easily accessible and siteless, only a small number of ECG patches were returned to the researchers for analysis. Even so, the study demonstrates how digital health can change both research and healthcare. The app made a research trial accessible to the general public without the need for travel or high costs to operate the trial.
Furthermore, seventy-six percent of participants who received a notification sought medical attention, whether it was a telemedicine provider or a nonstudy provider. The participants engaged with the healthcare system simply because of an app notification. With the rise of more advanced technology, it is possible that digital health can promote engagement with the healthcare system by making it easier to contact healthcare providers.
Written by Shayna Goldenberg
- Perez, M., Mahaffey, K., Hedlin, H., Rumsfeld, J., Garcia, A., Ferris, T., Balasubramanian, V., Russo, A., Rajmane, A., Cheung, L., Hung, G., Lee, J., Kowey, P., Talati, N., Nag, D., Gummidipundi, S., Beatty, A., Hills, M., Desai, S., Granger, C., Desai, M. and Turakhia, M. (2019). Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation. New England Journal of Medicine, 381(20), pp.1909-1917.
- heart.org. (2019). What is Atrial Fibrillation (AFib or AF)?. [online] Available at: https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af [Accessed 20 Nov. 2019].
- Heart and Stroke Foundation of Canada. (2019). Electrocardiogram. [online] Available at: https://www.heartandstroke.ca/heart/tests/electrocardiogram [Accessed 20 Nov. 2019].