Comparative study of a single lead ECG in a wearable device

Area of Science:

• Biomedical Engineering
• Cardiology
• Digital Health

Background:

• Wearable health devices offer accessible electrocardiograph (ECG) functionality for cardiac monitoring.
• High signal quality for accurate diagnosis remains a challenge for consumer-acquired ECGs.
• Effective signal conditioning is essential to render wearable ECG data clinically useful.

Purpose of the Study:

• To evaluate the heart rate (HR) performance of the HeartKey® Test Watch, a wrist-worn single-lead, dry electrode wearable.
• To compare the HR accuracy of the HeartKey Test Watch against two criterion devices: the Bittium® Faros 180 and the HeartKey Chest Module.

Main Methods:

• Simultaneous ECG acquisition across three devices during a multi-stage protocol (sitting, walking, standing) simulating real-life motion.
• Processing of raw ECG data from the HeartKey Test Watch and Chest Module using HeartKey software.
• Comparison of outputted HR data accuracy against a gold-standard criterion device, including beat rejection analysis for noise assessment.

Main Results:

• HeartKey software processed ECG data from the wrist wearable to generate HR metrics closely matching criterion devices.
• Bland-Altman analysis revealed mean absolute HR differences within the ANSI EC13 required range (0.74-1.21 bpm).
• The HeartKey Test Watch exhibited a higher beat rejection rate (8.5%) compared to the Chest Module (~0%) due to motion-induced high-frequency noise.

Conclusions:

• HeartKey software achieves highly accurate HR performance comparable to a gold-standard device when processing challenging ECG data from a single-lead, dry electrode wrist wearable.
• The study validates the potential of wearable ECG technology for clinical applications, provided effective signal processing.
• Signal conditioning is critical for overcoming noise challenges in wearable ECGs during motion.