A Watch-Type Electrocardiography Is a Reliable Tool for Detecting Paroxysmal Cardiac Arrhythmias

Abstract

Background: A substantial proportion of cardiac arrhythmias are paroxysmal in nature, and 12-lead electrocardiography (ECG) and Holter monitoring often fail to detect paroxysmal arrhythmias. We designed and evaluated a watch-type, electrocardiograph-recording, wearable device (w-ECG) to overcome the limitations of 12-lead ECG and Holter monitoring. Methods: We prospectively enrolled 96 patients with symptoms assumed to be related to cardiac arrhythmias. Electrocardiography recording was performed with both the w-ECG and Holter monitoring. Detection of any arrhythmia was the primary outcome endpoint and was compared between the w-ECG and Holter monitoring. Results: Any arrhythmia was detected in 51 (53.1%) and 27 (28.1%) patients by the w-ECG and Holter monitoring, respectively (odds ratio (OR) = 2.9, p < 0.001). The w-ECG was superior to Holter monitoring for the detection of clinically significant arrhythmias (excluding atrial premature contraction, ventricular premature contraction, and non-sustained atrial tachyarrhythmia) (OR = 2.34, p = 0.018). In 27 (28.1%) patients, cardiac arrhythmias were detected only by the w-ECG, with atrial fibrillation being the most frequent case (13 patients). Based on ECGs recorded by using the w-ECG, 17 patients (17.7%) received therapeutic interventions, including radiofrequency catheter ablation. Conclusions: The w-ECG is capable of recording ECGs of good quality, with a discernable P wave and distinguishable QRS morphology. The ability of the w-ECG to detect cardiac arrhythmias was significantly better than that of Holter monitoring, and a significant proportion of patients received therapeutic intervention based on ECGs recorded by the w-ECG.

Keywords: arrhythmia; electrocardiography; smartwatch; watch-type ECG; wearable device.

Figure 1

The watch-type ECG device (w-ECG): (A) Representative image of the w-ECG. (B) ECG recorded by the w-ECG. (C) Processing of the w-ECG. Recorded ECGs are sent to the centralized server and analyzed by an artificial intelligence-based algorithm. ECG: electrocardiography.

Figure 2

Study flow.

Figure 3

Atrial fibrillation and ventricular tachycardia detected by the w-ECG. Patients #7, #17, and #79 were diagnosed with atrial fibrillation based on w-ECG recordings. The w-ECG was able to record rate-dependent functional QRS widening in patient #79 (blue arrows). Patient #21 was diagnosed with ventricular tachycardia and the initiation point was clearly captured (red arrow). w-ECG: watch-type ECG device.

Figure 4

Paroxysmal supraventricular tachycardia and atrial tachycardia detected by the w-ECG. Patient #55 was diagnosed with paroxysmal supraventricular tachycardia using the w-ECG, and electrophysiology study revealed atrioventricular nodal reentrant tachycardia, fast–slow type. Different T-wave morphology during tachycardia and sinus rhythm (black arrows) is compatible with atrioventricular nodal reentrant tachycardia, fast–slow type. Sudden termination of tachycardia was clearly recorded, and the mode of termination was A-no-V, suggestive of paroxysmal supraventricular tachycardia. This image suggests that the w-ECG can detect subtle differences in T-wave morphology. Patient #19, with a prior history of radiofrequency catheter ablation for atrial fibrillation, was diagnosed with narrow QRS complex tachycardia using the w-ECG. Electrophysiology demonstrated that the tachycardia was atypical atrial flutter, and it was successfully ablated. w-ECG: watch-type ECG device.

Figure 5

Diagnostic yield of Holter monitoring versus the w-ECG. The w-ECG was superior to Holter monitoring at detecting all arrhythmias and major arrhythmias. OR: odds ratio; w-ECG: watch-type ECG device.