Can atrial lead system ameliorate the diagnosis of atrial arrhythmias?

The diagnosis of atrial arrhythmia is problematic due to low signal voltage and susceptibility to noise and artifacts. Electrocardiogram (ECG) is a commonly used, cost-effective tool for diagnosing cardiac arrhythmias. However, detecting certain waves, such as P and f-waves, in a standard 12-lead ECG is still challenging and frequently cause false positive diagnoses of atrial arrhythmias. Therefore, improving the quality of ECG signals is crucial to minimize false positives and enhance the accuracy of diagnosis. To address this issue, recent studies have explored optimizing lead configurations to improve signal strength and noise resistance for smart and mobile health (mHealth) applications. In this work, we hypothesized that using the newly developed Atrial Lead System (ALS) with an optimal lead configuration could improve the signal quality of ECGs, leading to a better diagnosis of atrial arrhythmias. To test our hypothesis, we recorded 1-minute ECGs from individuals with Normal Sinus Rhythm (NSR) and various atrial arrhythmias, including Atrial Fibrillation (AF), Atrial Flutter (AFL), and Left Atrial Enlargement (LAE). We compared the ECG data obtained from the lead-II of the Standard Limb Lead system (SLL-II) with the leads of ALS (AL-I and AL-II). From each sample in the NSR and AF groups, we computed the atrial characteristic features, Atrioventricular amplitude ratio (A/Vpp ratio), and the PR and RR intervals. Statistical analysis, correlation analysis, and reliability analysis using Bland-Alman plots were performed to assess the significance of the findings. The results showed significant differences in amplitude, duration, area, and A/Vpp ratio between the NSR and AF populations when comparing SLL-II, AL-I, and AL-II. To further validate the enhancement in signal quality, we analyzed the Signal-to-Noise Ratio (SNR) by calculating the ratio of atrial amplitude (AA) to the root mean square value of high-frequency noise (gamma HFN). The analysis revealed a significant improvement in AA and SNR (AA/gamma HFN) when using AL-I and AL-II than SLL-II for both NSR and AF conditions. Correlation analysis and Bland-Alman plots confirmed the reliability of the signal quality enhancement provided by ALS with SLL-II. The results of this work showed that the amplitude of atrial activity from the optimized lead placement in ALS is nearly twice that of SLL-II. The findings of the proposed hypothesis may influence diagnostics specialists to implement the optimized lead configuration of ALS in long-term, ambulatory, telemetric, and mHealth devices for enhanced monitoring and reliable diagnosis of different atrial arrhythmias.