Smartwatch 12-lead ECG: Accuracy of standard 12-lead electrocardiography from serial single lead acquisitions

Teddy ML Curtis, Todd T Schlegel, Martin Ugander

Background: Clinical electrocardiography (ECG) is performed using a standard 12-lead ECG to assess for signs of heart disease. However, until recently, it has not been possible to acquire a standard 12-lead ECG using only a smartwatch.

Aims: To evaluate the accuracy, compared to conventional standard 12-lead ECG, of a modified 12-lead ECG and a standard 12-lead ECG, respectively, acquired using only serial acquisitions from different lead positions that can be acquired using a smartwatch.

Methods: Healthy volunteers (n=91) underwent a standard 12-lead ECG twice using a conventional system and identical electrodes. Using the same electrodes, serial acquisitions were performed using only leads that can be acquired using a smartwatch, thus generating: 1) a modified 12-lead ECG using chest-to-arm leads as surrogates for leads V1-V6, and 2) a standard 12-lead ECG using a novel proprietary algorithm. The difference between ECGs was quantified as the average root mean square error per lead for average beats of all 12 leads.

Results: The difference comparing two repeated conventional standard 12-lead acquisitions was (median [interquartile range]) 14.4 [10.7-18.8] microV; comparing the conventional and smartwatch standard 12-lead ECG was 20.3 [15.6-24.9] microV; and comparing the conventional and the smartwatch modified 12-lead ECG was 68.6 [57.1-88.8] microV.

Conclusions: This study provides proof-of-concept for the accuracy of a novel smartwatch standard 12-lead ECG that is effectively equivalent to the conventional standard 12-lead ECG, thus overcoming the shortcomings of a modified 12-lead ECG approach.