From Wrist to Precision: Enhanced Atrial Flutter Detection with Modified Smartwatch Single-Lead Electrocardiogram...

Area of Science:

• Cardiology
• Medical Devices
• Electrocardiography

Background:

• Smartwatches like the Apple Watch (AW) are used for detecting atrial fibrillation (AF).
• Traditional single-lead ECG configurations may misdiagnose atrial flutter (AFL).
• Modified smartwatch lead positioning may enhance AFL diagnostic accuracy.

Purpose of the Study:

• To evaluate the diagnostic accuracy of standard lead-I (AW-I) versus modified lead-II (AW-II) smartwatch ECG configurations for atrial flutter (AFL).
• To assess the impact of device positioning on AFL detection by physicians across different specialties.

Main Methods:

• Obtained standard AW-I and modified AW-II ECG recordings from 75 patients (25 AFL, 25 AF, 25 SR).
• 20 physicians from 4 specialties independently analyzed 100 tracings (75 AW-I, 25 AW-II).
• Assessed diagnostic accuracy for AFL detection using both configurations.

Main Results:

• Physicians had poor AFL detection rates with AW-I (11.6%), frequently misdiagnosing it as AF.
• Diagnostic accuracy for AFL significantly improved with AW-II, exceeding 80% across specialties (P=0.001).
• Variable atrioventricular conduction was linked to correct AFL diagnosis solely via AW-II (OR 1.85, P=0.012).

Conclusions:

• Standard smartwatch lead-I ECG configurations are unreliable for AFL detection and prone to misdiagnosis as AF.
• A simple modification to lead-II positioning substantially enhances smartwatch-based AFL diagnostic accuracy.
• This AW-II modification is valuable for rhythm identification in clinical decision-making, including post-ablation surveillance.