Axis Determination on an EKG

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Axis Determination on an EKG

• by
• Don Hudson, D.O., FACEP/ACOEP

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I prefer to keep it real simple !!

• There are lot of nuances that will not be picked
  up this way but that is in the area for the
  Cardiologist.
• First do the EKG
• Lay it down and put your thumbs over leads I and
  aVf.
• Point them in the same direction as the QRS.

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Place your thumb over leads I aVf pointing in
the direction of the QRS
NORMAL
LAD
RAD
NO MANS LAND
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Why do you care about the Axis

• Normal is simply obvious
• Left Axis Deviation indicated that ½ of the two
  left Bundles of HIS is not working either the
  anterior or posterior branch. In this simple
  format we dont care which one, anterior or
  posterior.
• Right Axis Deviation indicates a probable Rt.
  Ventricle Hypertrophy

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No Mans Land Axis

• This problem with this lead is it may represent
  either an extreme RAD or an extreme LAD.
• The point is in the simplified version you
  recognize it as abnormal and it may be an
  indication of either a left hemiblock or right
  ventricular hypertrophy.
• Either finding requires further testing and
  evaluation of the patient.

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Right Axis Deviation

• We have already considered that this finding
  indicates right ventricle hypertrophy
• Since this side of the pump normally pumps to the
  lung the consideration of a disease process
  causing the vessels in the lung to be
  non-complient and therefore more difficult for
  the heart to pump blood into.

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What is most important

• These are all important factors.
• You will most often see LAD in the general ER
  patient.
• The other abnormality you will need to add to the
  axis determination is Bundle Branch Blocks
• These will be gone over in another section