distinguishing heart blocks EKG

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Specializes in ICU.

Hi everyone,

I am practicing to get my tele certification. The only thing I am having difficulty with is distinguishing between 2nd degree AV block type 1 and 2. I know that in type 1, usually the PR interval gets longer, longer, longer, then a block. But in some of my practice strips, this is not always the perfect case.

I figured someone here would be able to give a good explanation of the two!!! Thanks for any help. I take my exam on Thursday and I definitely want to pass. I've been an RN since the end of September and work on a tele floor, so it will be nice to finally read my own strips.:yeah::redpinkhe

Nicole:D

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Specializes in ER/ICU/Flight.

hey nicole,

av blocks can be hard. in a mobitz 1 the conduction through the av node is delayed slightly with each beat until it finally drops one, then the pr interval "resets" itself. so the qrs is getting farther away with each conducted beat. interestingly enough, this rhythm was diagnosed prior to the onset of ekgs and the physician was just listening to the s1 and s2 sounds. sounds pretty tough (no pun intended).

with a mobitz 2 or classic heart block, an occasional beat is not conducted through the av node. with either of these 2 rhythms you can have 2:1, 3:1, etc or a mixture of everything, which makes it more difficult to determine. the best way of approaching it is just to look at the pr interval. you shouldn't have to break out your calipers, i've heard cardiologists-including my grandfather-say: if you're using calipers you're putting too much energy into it, don't split hairs over 1/100th of a second. if the pr interval is the same with each conducted beat and less than .20, then you have a type 2. if the interval is varying in a discernable pattern, then you have a type 1. but the bottom line of either rhythm is the hemodynamic stability. how are they tolerating the rhythm?

anyway, hope that helps some. good luck on your test, most tracings are notoriously horrible. don't let it throw you off track!

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Specializes in Emergency.

I hope I can break it down simply for you:

In a first degree heart block, there is a normal sinus rhythm, with P waves regular at a normal rate, but the P-R interval is > than 0.20. There is always a P-wave for every QRS complex, just a longer time.

In a second degree heart block (also called Wenckebach or Mobitz I), you have normal sinus P-waves at a normal rate, but there are more P-waves than QRS complexes. Typically, there is a P-wave followed by a QRS that is normal, then the next P-wave with a longer delay before the next QRS, then a P-wave with an even longer delay, then a P-wave WITHOUT a QRS, before starting the sequence over again.

To go on, in second degree, you will have the P-wave without the QRS every second beat

In third degree, there is total disassociation, and the P-wave will be regular, but the QRS will never be consistent.

Hope this helps, it's hard to describe without showing strips.

Amy

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Specializes in ICU.

Thanks everyone for the help. I passed my exam today. I got 101%! (there were 3 bonus questions). Yay, I can read my own strips now:yeah:

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Specializes in Cardiac Telemetry, ED.

Congratulations!

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First degree:

You are dating a guy and you tell him to pick you up at 8 o'clock. Instead the first date he picks you up at 8:15..second date..8:30...third date....9:00.(PR INTERVAL is getting longer and longer.)

He always shows up (QRS) BUT IS ALWAYS LATE AND LATER LATER for each date. You forgive him but he starts all over again...8:15...8:30....9:00 HE IS PROGRESSIVELY LATE BUT ALWAYS SHOWS UP.

Second degree TYPE 1.

You are dating this guy for quite sometime now. He is still late.(PR INTERVAL) He is doing the same crap as before (SAME AS FIRST DEGREE) 8:15..8:30...(later and later each date) BUT THIS TIME.....Hes late...he's late...he's late..but then..HE DOESNT SHOW UP! (QRS) HE IS PROGRESSIVELY LATE and DOESNT SHOW UP.

But there is something about him you like and you forgive him and he does it all over...late..late..late..NO SHOW!

Second degree TYPE 2:

So you decide to have a talk with the guy. He said he is going to try to not be late.

He is still late but least he is constant. Instead of the agreed time of 8:00..he keeps showing up at 8:30...8:30..8:30..then BAM HE DOESNT SHOW UP. You are devesatated!

(ALSO HE COULD OF BEEN ON TIME ON TIME ON TIME (PR 0.12-.20) BUT AFTER AWHILE HE DOESNT SHOW UP (QRS) YOU HAD NO WARNING. YOU ARE HEART BROKEN.

HE IS CONSTANT BUT THEN FOR NO REASON DOESNT SHOW UP.

You forgive him and decide to marry this IDIOT WHICH LEADS TO THIRD DEGREE HEART BLOCK.

He is on the couch..always on the couch..always there doing his own thing. You are always there too (P wave) but you are doing your own thing as well.

HE IS ALWAYS THERE BUT YOU WANT NOTHING TO DO WITH HIM.

HEART RATE GIVES 3RD DEGREE AWAY...SLOOOOOW, dont confuse it for whatever reason with 1st DEGREE.

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Specializes in Critical Care.

Have fun with the 2:1 blocks. ;)

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:DNuala thanks so much love :redpinkhethat :yeah:..........I learned it the same way except they made it a married comple first the go every where together but later more distant till finally they do there own thing .............so love this explanation because it helps you remember the blocks any way thanks

Love little tricks that come with a story to help you remember !!!!!!!!!!!!!:up::D:loveya:

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Specializes in Cardiac Telemetry, Emergency, SAFE.
First degree:

You are dating a guy and you tell him to pick you up at 8 o'clock. Instead the first date he picks you up at 8:15..second date..8:30...third date....9:00.(PR INTERVAL is getting longer and longer.)

He always shows up (QRS) BUT IS ALWAYS LATE AND LATER LATER for each date. You forgive him but he starts all over again...8:15...8:30....9:00 HE IS PROGRESSIVELY LATE BUT ALWAYS SHOWS UP.

Thats a wonderful way to remember, but I thought 1* AVB was a PR greater than .20? Thats it. Whats this with the PRI being progressively longer? Im lost now. lol

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This helped me remember...

If your R is far from P, then you have a 1st degree.

Longer, longer, longer, drop...then you have a Wenckebach.

If your Ps don't go through, then you have a Mobitz 2.

If your Ps don't agree, then you have a 3rd degree.

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Specializes in Cardiac.
This helped me remember...

If your R is far from P, then you have a 1st degree.

Longer, longer, longer, drop...then you have a Wenckebach.

If your Ps don't go through, then you have a Mobitz 2.

If your Ps don't agree, then you have a 3rd degree.

Thank you for this!

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