"Lead Thirteen" Electrocardiograph

Understanding cardiac arrhythmias

“…P wave identification can sometimes be facilitated by using the Lewis lead. 8 Similarly, a transoesophageal lead can be used to identify P waves in difficult cases. The ECG is usually recorded on a time scale of 25 mm/s on the horizontal axis and a voltage sensitivity of 0.1 mv/mm on the vertical axis.…”