Dawn's picture

This six-second monitor strip was from a patient who was designated "Do Not Resuscitate", and whose heart rhythm was slowing dramatically.  It shows an idioventricular escape rhythm, with very wide QRS complexes and only two complexes in six seconds. (The top arrows mark three-second segments.)  If you look closely at the points marked by the lower arrows, you will see small, uniform, regular P waves.  The mechanism leading to this agonal rhythm was complete heart block.  A longer strip would show the P waves as all alike, and fairly regular, but slowing.  

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ekgpress@mac.com's picture

Good teaching example of a slow code rhythm. In addition to highlightlight what appears to be slow atrial activity - a few other teaching points might be made:

  • We can't really tell if the rhythm we see is slow IVR (IdioVentricular Rhythm) vs an Agonal rhythm - since we just don't see what comes next. Obviously in either case prognosis is dismal unless something can be done to increase heart rate.
  • IF this was in fact a slow idioventricular escape rhythm - and the next escape beat came at the same R-R interval - then we can estimate the escape rate by the usual "Rule of 300" = Divide 300 by the number of boxes in the R-R interval. Since the R-R interval here = ~ 25 large boxes - we estimate the rate = 300/25 ~ 12/minute. I like to illustrate that the Rule of 300 works equally well for slow as well as faster rates.

Ken Grauer, MD  www.kg-ekgpress.com   [email protected] 

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