Fig. 1.

Simultaneous acquisition and synchronous pairing of 12-lead and 6-lead ECGs. A Illustrations of the standard acquisition positions for each device: 12-lead ECG in the supine position and 6-lead ECG in the sitting position. In the supine position, the 6-lead device was held with both hands, and the left leg electrode was simulated by attaching an additional electrode to the left ankle (highlighted in red). B In this study, to account for positional effects that may influence signal morphology, both 12-lead and 6-lead ECGs were recorded in both supine and sitting positions. Although the HATIV device records a continuous 30-s 6-lead ECG, only the 10-s segment temporally aligned with the 10-s 12-lead ECG was used for synchronous analysis