Lewis Leads & Invisible P’s

    NextPrevious

    Lewis Leads & Invisible P’s

    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

    Lewis Lead (diagram 2)

     

    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

    Regular 12-Lead; Leads I & II

    Lewis Lead I

    Lewis Lead I

    Lewis Lead II

    Lewis Lead II

    And there you have it folks! Feel free to throw that one at your next VT vs AFib RVR with aberrency!

     

    Resources:

    The Lewis Lead

    EMCrit Wee: The Lewis Lead and a course in ECGs with Christopher Watford

    • Welcome! This is the website for the Mount Sinai Emergency Ultrasound Division. It serves as an information resource for residents, fellows, medical students and others seeking information about point-of-care ultrasound. There is a lot ofRead more

    • Slow down your tachycardia (but not really)

      You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate wasRead more

    • Otitis externa: use the ear wick!

      Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear”Read more

    • Reach for the COWS

      Your patient in intake is miserable. Doubled over, complaining of pain everywhere, sweating, ill-appearing but not unstable. He tells you that the last time he used heroin was two nights ago, and he is askingRead more

    • Tis the season, summer edition

      As the late spring rains have begun to fade and the temperature rises mercilessly into the 80s and beyond, summer is finally upon us. And with summer comes a host of diseases for the emergencyRead more

    • Meet the newest member of your team

      We have a new resource in the Sinai ED. Say hello to your friendly ED pharmacist. In the past several years, the ED pharmacy has been centralized in a non-ED location. We all know wellRead more

    • In the spirit of roasts and fire-breathing dragons

      You’re on a lovely amble through the backcountry when suddenly you see smoke rising nearby and catch a whiff of a familiar scent that throws you back to your med school OR days: burning flesh.Read more

    • E-point Septal Separation in the Patient with Congestive Heart Failure

      Perhaps never explained so clearly, Cisewki and Alerhand’s article on EPSS is a wonderful read. Bottom line to remember: EPSS > 7 mm was 87% sensitive and 75% specific at identifying reduced EF (<50%).  This isRead more

    • Lidocaine for cough?

      Whether it’s asthma, a U.R.I., or post nasal drip as the cause, cough is a common enough complaint encountered by emergency physicians everywhere. Of course you must always rule out the dangerous causes of coughRead more

    NextPrevious