key: cord-0844412-z9ulwgqk
authors: Strik, Marc; Caillol, Théo; Ramirez, F. Daniel; Abu-Alrub, Saer; Marchand, Hugo; Welte, Nicolas; Ritter, Philippe; Haïssaguerre, Michel; Ploux, Sylvain; Bordachar, Pierre
title: Validating QT-Interval Measurement Using the Apple Watch ECG to Enable Remote Monitoring During the COVID-19 Pandemic
date: 2020-06-01
journal: Circulation
DOI: 10.1161/circulationaha.120.048253
sha: 7bf651a906a21f0c84f8b726d2f6822aded2748e
doc_id: 844412
cord_uid: z9ulwgqk

nan

There was excellent agreement between cardiologists on whether recordings were acceptable for QTc measurements (κ=0.92). Interobserver agreement for QTc measurements was similarly high with a median absolute error of 9 milliseconds (interquartile range, 5-15 milliseconds) and an intraclass correlation coefficient of 0.92 (95% CI, 0.85-0.95). Compared with the 12-lead ECG, the median absolute error in QTc was 18 milliseconds for AW-I (interquartile range, 9-35 milliseconds), 20 milliseconds for AW-II (interquartile range, 8-33 milliseconds), and 16 milliseconds for AW-LAT (interquartile range, 8-27 milliseconds). There were no significant differences in absolute offset between smartwatch positions. Bland-Altman analyses revealed a bias of −5 milliseconds (95% limits of agreement, −65 to 54) with AW-I, −9 milliseconds with AW-II (95% limits of agreement, −67 to 50), and −11 milliseconds (95% limits of agreement, −60 to 37) with AW-LAT. The negative bias suggests that using the smartwatch slightly overestimated the QTc interval. T waves were significantly higher in AW-LAT than in AW-I and AW-II (0.28 mV versus 0.20 mV and 0.19 mV, respectively; P<0.001, ANOVA). Tracings with T-wave amplitudes >1 mV demonstrated lower absolute errors in AW-I (21±16 milliseconds versus 30±25 milliseconds; P=0.03, unpaired t test).

In our study, Apple Watch electrocardiographic tracings allowed adequate QT measurements when the smartwatch was worn on the left wrist in 85% of patients. This figure increased to 94% when the smartwatch was moved to alternative positions. Performance depends on factors such as electrocardiographic tracing quality and T-wave amplitude. Therefore, identifying the best smartwatch position (ie, T-wave mapping) at baseline may improve accuracy. Other electrocardiographic systems were not evaluated but may be similarly valuable 4,5 such as the Kardia 6 L system (AliveCor, Mountain View, CA), which has received US Food and Drug Administration clearance for QT measurement. Overall, this technology has the potential to facilitate remote QT monitoring, including among quarantined outpatients on QT-prolonging treatments.

The data from this study are available from the corresponding author on reasonable request.

The QT interval in patients with COVID-19 treated with hydroxychloroquine and azithromycin

Ventricular arrhythmia risk due to hydroxychloroquine-azithromycin treatment for COVID-19. American College of Cardiology

Single-lead ECG recordings including Einthoven and Wilson leads by a smartwatch: a new era of patient directed early ECG differential diagnosis of cardiac diseases?

QTC intervals can be assessed with the AliveCor heart monitor in patients on dofetilide for atrial fibrillation

A wearable remote monitoring system for the identification of subjects with a prolonged QT interval or at risk for druginduced long QT syndrome

None.