Rhythm interpretation and diagnosis of AV Blocks
Episode 33
April 24, 2012

When interpreting rhythms, always do these three things:
1. Find out what the atrium is doing
2. Find out what the ventricle is doing
3. Figure out the relationship between the atrium and ventricle (PR-interval)
The answer usually lies in the PR-interval !
 
  • 1st Degree AV Block = “delay” > 200ms at AV node or His bundle.

When the P:QRS>1, consider 2nd and 3rd degree AV Blocks

  • 2nd Degree AV Block = Not every atrial impulse goes through to the ventrcles. (ie P:QRS >1)
    • Mobitz Type I (Wenckebach) -Each atrial impulse has longer and longer delay until it fails to conduct to the ventricle. Progressive PR-interval lengthening before a non condected beat
      • Usually no treatment
    • Mobitz Type II - typically due to block below AV node in His bundle. Some but not all impulses are transmitted to the ventricles WITHOUT progressive PR lengthening
      • May progress to 3rd degree block and usually merits a pacemaker
  • 3nd Degree AV Block  = P waves march out normally at 60-100 bpm with no relation to the ventricular rate which is typically slower than sinus or the atrial rate
 
Rhythm interpretation and diagnosis of AV Blocks
Episode 33
April 24, 2012

When interpreting rhythms, always do these three things:
1. Find out what the atrium is doing
2. Find out what the ventricle is doing
3. Figure out the relationship between the atrium and ventricle (PR-interval)
The answer usually lies in the PR-interval !
 
  • 1st Degree AV Block = “delay” > 200ms at AV node or His bundle.

When the P:QRS>1, consider 2nd and 3rd degree AV Blocks

  • 2nd Degree AV Block = Not every atrial impulse goes through to the ventrcles. (ie P:QRS >1)
    • Mobitz Type I (Wenckebach) -Each atrial impulse has longer and longer delay until it fails to conduct to the ventricle. Progressive PR-interval lengthening before a non condected beat
      • Usually no treatment
    • Mobitz Type II - typically due to block below AV node in His bundle. Some but not all impulses are transmitted to the ventricles WITHOUT progressive PR lengthening
      • May progress to 3rd degree block and usually merits a pacemaker
  • 3nd Degree AV Block  = P waves march out normally at 60-100 bpm with no relation to the ventricular rate which is typically slower than sinus or the atrial rate

Learn more about clumped beats and AV Blocks…

 
  1. old-ekgumem posted this
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