EKG of the Week


+ EKG Interpretation

Dr. Ohlbaum's Explanation

So, how do you get a BLANK or nearly blank lead II?!?

At quick glance you notice that the lead II on this ekg has only tiny tiny blips where there should be QRS complexes. How does that happen? You might also notice that some of the other limb leads look “odd”. You can get a blank V lead by leaving off that electrode but there is no “lead II electrode”:

  • Lead II - A comparison between extremities (right arm and left leg) as part of the triangle.
  • Lead I - Goes from right arm to left arm, lead II from right arm to left leg, and lead III from left arm to left leg, making a triangle around the heart.

For great diagrams see the LITFL article about axis

How can a comparison be nearly blank?

If you remember how to perform an ekg, there are actually 4 limb leads placed, right arm, left arm and left leg for that triangle but there is also a right leg lead placed. It is a grounding lead. The right arm and right leg come off the machine next to each other so it is really easy to reverse them.

What happens if you reverse right arm and right leg?

Lead I is supposed to compare right arm to left arm but here compares Right leg to left arm so just “odd”, not like any standard lead

Lead II is supposed to compare right arm to left leg, across the heart but here it compares from the right leg to the left leg totally “missing” the heart so all we see is tiny residual blip of electrical activity.

Based on the V leads, I think this is NSR, but the limb leads are “uninterpretable” and the ekg needs to be repeated.

Further Reading:

Life in the Fast Lane: Axis Discussion

Follow up EKGs:

Full EKG Index