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I've been doing the Bob Page 15-lead. Takes <1 minute to switch V4/V5/V6 electrodes and run it.
12 Lead STEMI suspicion w/ LBBB and PPM's
- Thread starter 46Young
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I've been doing the Bob Page 15-lead. Takes <1 minute to switch V4/V5/V6 electrodes and run it.
TomB
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Thanks, vquintessence!
With LBBB and paced rhythm both the ST-segment and T-wave should be deflected opposite the majority (main deflection) of the QRS complex, which is almost always the terminal deflection of the QRS complex (last wave).
In addition, there should be a relationship between the size of the QRS complex and the size of the secondary ST/T-wave abnormality in the opposite direction. So, a small S-wave should yield a tiny bit of ST-elevation and upright T-wave, whereas a huge S-wave can yield a startling amount of ST-elevation and huge T-waves.
That's why it's important to consider the ST/QRS ratio with LBBB (credit to Stephen Smith, M.D. of Dr. Smith's ECG Blog). When the ST-segment is deviated more than 0.2 the depth of the S-wave (or height of the R-wave in the case of upright QRS complexes) it indicates acute STEMI.
What's cool about this discovery is that it improves both the sensitivity and specificity of Sgarbossa's criterion that requires 5 mm of discordant ST-elevation.
I give an overview with graphics here:
Excessive discordance as a marker of acute STEMI in LBBB
So I still use Sgarbossa's criteria but in a modified form. I look for either 1 mm of concordant ST-elevation, 1 mm of concordant ST-depression, or "excessive discordance" (ST/QRS ratio > 0.2) which seems to be working quite well.
One of my favorite topics!
Tom
With LBBB and paced rhythm both the ST-segment and T-wave should be deflected opposite the majority (main deflection) of the QRS complex, which is almost always the terminal deflection of the QRS complex (last wave).
In addition, there should be a relationship between the size of the QRS complex and the size of the secondary ST/T-wave abnormality in the opposite direction. So, a small S-wave should yield a tiny bit of ST-elevation and upright T-wave, whereas a huge S-wave can yield a startling amount of ST-elevation and huge T-waves.
That's why it's important to consider the ST/QRS ratio with LBBB (credit to Stephen Smith, M.D. of Dr. Smith's ECG Blog). When the ST-segment is deviated more than 0.2 the depth of the S-wave (or height of the R-wave in the case of upright QRS complexes) it indicates acute STEMI.
What's cool about this discovery is that it improves both the sensitivity and specificity of Sgarbossa's criterion that requires 5 mm of discordant ST-elevation.
I give an overview with graphics here:
Excessive discordance as a marker of acute STEMI in LBBB
So I still use Sgarbossa's criteria but in a modified form. I look for either 1 mm of concordant ST-elevation, 1 mm of concordant ST-depression, or "excessive discordance" (ST/QRS ratio > 0.2) which seems to be working quite well.
One of my favorite topics!
Tom
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AnthonyM83
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What a coincidence...that also happens to be official AHA recommendations, as a BVM is a two person device. If you only have one, then you do it with one, but it's meant for two.
As far as witholding medications until after the 12-Lead, I would submit that ASA might be appropriate to give as soon as you know suspect possible cardiac related chest pain, since it's the one thing that will really be giving the patient a chance at a good outcome (other than us recognizing the STEMI if he has one). I don't think it would change the EKG that would be run a minute later.