# ST elevation in the presence of a pacemaker



## rhan101277 (Nov 20, 2010)

I just wanted everyone to see this video about ST elevation in the presence of a pacemaker.  I had one this weekend and they don't happen often so I thought it would be good to post.  Many people think it is not possible to have ST elevation with a paced rhythm, however it is.  

http://vimeo.com/1139092


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## Medic785 (Nov 20, 2010)

Great video...thank you for posting!


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## Veneficus (Nov 21, 2010)

rhan101277 said:


> I just wanted everyone to see this video about ST elevation in the presence of a pacemaker.  I had one this weekend and they don't happen often so I thought it would be good to post.  Many people think it is not possible to have ST elevation with a paced rhythm, however it is.
> 
> http://vimeo.com/1139092



I never heard anyone say it was impossible, and logically it would depend on where the pacemaker electrodes are.

Could you tell me why some people think it is impossible?


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## Smash (Nov 21, 2010)

Veneficus said:


> I never heard anyone say it was impossible, and logically it would depend on where the pacemaker electrodes are.
> 
> Could you tell me why some people think it is impossible?



It is a long held EMSism that it is impossible to determine elevation in paced rhythms or when a left bundle branch block is present. It's also commonly held that a new left bundle block _must_ indicate an infarct. I've no idea why that is the case, but for some reason Sgarbossa's criteria are not that commonly taught or understood. 

Why that is, I have no idea, that is merely my observation.


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## piranah (Nov 21, 2010)

interestingly, in a conversation I have had with a local ER MD. He stated that in the presence of an LBBB you cannot identify a infarct via 12-lead but by only obviously blood-work. I also agree with linuss, it all depends on the placement due to the fact that different placement or pacemaker site with augment the electrical conduction of the heart. As we all know the 12-lead is only a presentation of the electrical conduction, so having a separate pacemaker site will change the pattern viewed. I am open to new ideas though...


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## EMSrush (Nov 21, 2010)

Nice video- thanks! B)


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## TomB (Nov 21, 2010)

Nice video! If you're not aware, this is Dr. Smith from Dr. Smith's ECG blog. The point about concordant ST-elevation is well taken, but Dr. Smith's greatest gift is his research into discordant ST-elevation (or excessive discordance). With a paced rhythm or LBBB, a lead showing a negative QRS complex (lead V2 for example) would be expected to show ST-elevation. However, the ST-elevation should not be more that 0.2 (or 1/5) the depth of the S-wave (ST/QRS ratio). This modifies Sgarbossa's criterion that calls for at least 5 mm of discordant ST-elevation. Dr. Smith's ECG Blog is "must reading" for all ECG geeks.

http://hqmeded-ecg.blogspot.com/

Tom


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## Akulahawk (Nov 21, 2010)

Thanks for chiming in, Tom!


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