Diagnosis of arrhythmias is better shown by which ECG lead during intraoperative monitoring of their electrocardiogram (ECG).

Electrical axis of lead II is approximately 60deg from the right arm to the left leg, which is parallel to the electrical axis of the atria, resulting in the largest P-wave voltages of any surface lead. This orientation enhances the diagnosis of arrhythmias and the detection of inferior wall ischemia. Esophageal leads are even better than lead II for arrhythmia diagnosis ( general acceptance is not yet gained)