You ever have a tough time visualizing P waves on EKGs? Have no fear, a Lewis Lead EKG might just be the thing you need!
The Lewis Lead (aka S5) is a modified EKG obtained in a manner that basically triangulates atrial activity to help make the p-waves of your EKG more prominent. Lead placement includes the RA lead placed on the manubrium, the LA lead placed at the 5th intercostal space at the R sternal border, a LL lead placed at the right lower costal margin, and +/- the RL lead placed that the right leg.
In this configuration, lead I will travel directly over the atria, maximizing the size of the P wave
Why or when would you ever want to do this?
- EKGs with questionable P waves — those such as atrial fibrillation/flutter, wide complex tachycardia
What does this even look like?
![regular EKG](https://thephysiologist.files.wordpress.com/2015/10/normal-lead-i-ii.jpg)
![Lewis Lead I](https://thephysiologist.files.wordpress.com/2015/10/s5-atrial-lead-i.jpg)
![Lewis Lead II](https://thephysiologist.files.wordpress.com/2015/10/s5-atrial-leads-ii.jpg)
And there you have it folks! Feel free to throw that one at your next VT vs AFib RVR with aberrency!
Resources:
EMCrit Wee: The Lewis Lead and a course in ECGs with Christopher Watford