Study validates accuracy of smart watches in measuring rapid heart rate

Presented at Heart Rhythm 2018, first-of-its-kind study includes results from Apple Watch, Samsung Galaxy Gear and Fitbit Charge 2

A new study is the first to validate the accuracy of wrist-worn wearable devices in measuring induced paroxysmal supraventricular tachycardia (PSVT), or episodes of rapid heart rate. Three common wearable devices including the Apple Watch Series 2, Samsung Galaxy Gear S3 and the Fitbit Charge 2, were randomly assigned to patients to measure heart rate. The results of this study are scheduled to be presented on Friday, May 11 at Heart Rhythm 2018, the Heart Rhythm Society’s 39th Annual Scientific Sessions.

PSVT is marked by episodes of rapid heart rate (a heart rate above 100 beats per minute) that is caused by electrical impulses originating above the heart's ventricles. It affects approximately 2.5 per 1,000 adults and can impact people without any prior cardiovascular condition. PSVT is often a cause of palpitations, which is one of the most common complaints of patients who seek medical care from an arrhythmia or cardiology clinic. Wearable devices are very popular and are now widely used not only to track fitness levels, but to also capture and monitor heart rates with photoplethysmography (PPG) technology. However, few studies are published that evaluate the accuracy of these devices especially in an arrhythmic situation.

The study included 51 consecutive patients with a history of PSVT or paroxysmal palpitations who were schedule to undergo an electrophysiology study. The mean patient age was 44.4±16.6 years old and 53 percent were male. The study assessed three common wearable technologies, the Apple Watch Series 2 (Apple), Samsung Galaxy Gear S3 (Samsung) and the Fitbit Charge 2 (Fitbit). Patients were randomly assigned to wear two different devices, one on each wrist. The heart rate at baseline and during induced PSVT was evaluated.

The baseline heart rate ranged from 50 beats per minute (bpm) to 101 bpm. The accuracy of the wearables at detecting baseline heart rate within five bpm was 100 percent, 100 percent and 94 percent for Apple, Samsung and Fitbit, respectively. Heart rate during PSVT ranged from 108 bpm to 228 bpm. The accuracy within 10 bpm was 100 percent, 100 percent and 88 percent for Apple, Samsung and Fitbit, respectively. The rate or type of PSVT, age and sex did not influence device accuracy.

“Millions of people around the world are wearing smart watches or other devices that have the ability to track heart rate, and our study is the first of its kind to assess how effective and accurate these tools are for patients,” said Jongmin Hwang, MD, Seoul Asan Medical Center, Seoul, Korea. “As clinicians, we see these devices as a tool to help patients learn more about their heart health and become more proactive about self-care. With technology delivering information literally to their fingertips, we hope patients will be better informed and more inclined to speak with their doctor about their health.”

To further validate the results of this study, the authors attempted measurement during rapid atrial and ventricular pacing after successful ablation to stimulate tachycardia. Initial findings again show an acceptable accuracy, however there were performance differences between devices. The Apple Watch showed highest accuracy and Galaxy was comparable.