# Heart block

1. Can someome please explain to me a easy way to tell the difference between the different heart blocks thank you.
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2. ### About cns121

Joined: Dec '11; Posts: 30; Likes: 6

5 Comments

3. AV blocks? Lets see what I know...

First degree = PR interval >.20 and consistent

Mobitz I (wenckebach) = PR interval progressively longer until a QRS complex is dropped, then the cycle starts over (long, longer, longest, dropped - then you've got a wenchebach). P-P and R-R are irregular.

Mobitz II = intermittent non-conducted P waves... So, I BELIEVE that P-P is regular, while the R-R is irregular. Bad.

Third degree = P-P regular, R-R regular, but the PR interval changes - no association between the P wave and the QRS complex. Really bad.

BBB? QRS complex >0.10.

Thats all I got..
4. Oh, and the rate is generally brady on the types 2 and 3, in my experience...
5. This is an awesome resource: http://www.icufaqs.org/LastHeartBlock.doc
6. Thank you everyone for the information.
7. A first degree block has a PR interval >0.20. Pretty much benign but in rare cases will progress to a higher block.

Long, longer, drop.....you have a Wenckebach (Mobitz I). The PR interval gets longer and longer and then you have a missed beat.

If your P's don't always go through, then you have a Mobitz II. Here, the PR interval stays the same, then you will see a P wave without a QRS.

If your P's and Q's don't agree, you've got yourself a Third Degree. Also known as AV-dissocation. The P waves and QRS complexes are doing their own thing - think of the P's and QRS complexes as "no longer being married to each other."

Bundle branch blocks have a widened QRS complex, but you really need to do a 12-lead to confirm if it is a left or right BBB.

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