Temporary atrial and ventricular electrodes are frequently utilized for diagnosing and treating cardiac arrhythmias in children during the early postoperative period following cardiac surgery. Traditionally, lead I electrodes (right and left hand) are connected to atrial wires to facilitate arrhythmia diagnosis, resulting in high atrial signal display. In the manuscript we described an alternative method involving connecting atrial wires to the right and left leg electrodes, leaving lead I without the atrial ECG signal. This approach serves as a reference lead for postoperative arrhythmia detection, offering potential diagnostic clarity in selected clinical scenarios.