Comparative analysis of 6-lead and single-lead consumer-grade electrocardiograms: diagnostic accuracy, numerical agreement, and inter-rater reliability.

AIMS: Consumer-grade electrocardiogram (ECG) devices enable accessible rhythm monitoring. Recently developed six-lead handheld ECGs promise improved signal quality and diagnostic performance; however, comparative validation remains limited. Using 12-lead ECGs as reference, we compared diagnostic performance and quantitative agreement of a 6-lead and single-lead consumer ECGs.

METHODS AND

RESULTS

In this prospective single-centre study, 194 arrhythmia-clinic patients (498 paired recordings) underwent simultaneous 10-s 12-lead and 30-s 6-lead ECG acquisition, followed by sequential 30-s single-lead recording. Two blinded electrophysiologists interpreted ECGs. Diagnostic performance for predefined rhythm categories (sinus rhythm, atrial/ventricular premature complex, atrial fibrillation/flutter/tachycardia, atrioventricular block, others) was assessed by sensitivity, specificity, and accuracy. Waveform agreement was evaluated using Bland-Altman analysis and intraclass correlation coefficients (ICC) accounting for repeated measures. Sensitivity was higher for the 6-lead ECG for ectopic beats, atrial flutter, and first-degree atrioventricular block, with comparable specificity across categories. Overall diagnostic accuracy was 98.6% (95% confidence interval, 97.4-99.6) for the 6-lead and 96.9% (94.7-98.7) for the single-lead ECG. Agreement with the 12-lead ECG was higher for the 6-lead device for PR interval (ICC 0.89; 0.85-0.92) and QRS amplitude (0.96; 0.94-0.97) than for the single-lead device (0.57; 0.48-0.63 and 0.04; -0.13-0.21, respectively). Bland-Altman analysis demonstrated generally narrower limits of agreement for the 6-lead ECG. Findings were consistent in patient-level sensitivity analyses.

CONCLUSION

The 6-lead handheld ECG demonstrated a higher point estimate for diagnostic accuracy and closer agreement with the 12-lead ECG than the single-lead smartwatch ECG, supporting its use for arrhythmia assessment and interval measurement.