Synchronized Cardioversion - What happened?

[18G]

The wide-QRS, really tall T-waves on the 12-lead and the history of renal failure goes ding, ding for hyperkalemia induced. I would have more than likely wanted to give calcium and be thinking about albuterol.

It would be nice to know if this is a dialysis patient and if pt. has missed dialysis recently. Any way to find out what the patient's potassium was or find out what was causing this ECG?

Smash was the only one that mentioned about hyperkalemia. I'm mkinda surprised no one else suspected this as the cause based on the ECG and the PMH.

Hyperkalemia can easily cause wide-complex tachycardia and VT. And with an ECG looking like that I would suspect a K+ of over 7.

 

[firetender]

There are a couple of things I don't understand here.

My primary question is what's the deal with that monitor/defibrillator?

How on God's Green Earth did it interpret THREE places on each complex as possible targets? Not to mention that one was clearly right on the vulnerable phase if you compared lead II to Lead III.

Why didn't the medic recognize that yellow flag?

Are the machines designed to work off of Lead II and provide a multiplicity of choices? Does the medic have to choose which one to "go for"?

Is that a defective machine? (the monitor, not the medic!)

What do other users of that make and model need to know so this doesn't happen again.

Or has it been happening and nobody's talking?

Maybe our Mr. Physio-control can help enlighten us!

I've gone more in-depth on my BLOG.

 

[Jon]

I don't believe it was easily visible that the rate of sync markers didn't correspond to the rate of the QRS complexes. I've seen this before with sync cardio of afib, but in that case a lead change (to lead I) solved the problem.

Christopher - Thanks for sharing this. Is there any possibility of equipment malfunction here? Or was it just that due to the nature of the wide complex with a bundle branch block.

Also - did the monitor rate fluctuate much more randomly than the Pt's rate?

 

[Christopher]

Christopher - Thanks for sharing this. Is there any possibility of equipment malfunction here? Or was it just that due to the nature of the wide complex with a bundle branch block.

Also - did the monitor rate fluctuate much more randomly than the Pt's rate?

I don't believe it was a malfunction as I've seen it before, it's just the way the ECG "looks" and the way the markers look when superimposed. If you don't remember to pay attention to that, you won't notice.

Perhaps the monitor rate was wavering as well, I'll ask if they noticed anything like that. Good thought!

 

[epipusher]

18G brought up a very important question: Was the patient a dialysis patient, and if so, has the patient been going? For us,as him as well it seems, this leads to a very specific treatment path given the pmhx and the way the patient is presenting.

 

[systemet]

Opinions:

* I don't see why people have issue with this being VT. The 12-lead on the blog page looks suspicious for VT, there's even negative precordial concordance.

* VT can have any axis. A VT originating low in the RV (and probably a few other places) is going to have a leftward axis.

My primary question is what's the deal with that monitor/defibrillator?

It's oversensing. It has an algorithm that's designed to enable it to mark the R waves. This probably relies on seeing where the ECG complex makes an acute change in direction. This monitor is sensing 3 R waves for each complex, inappropriately.

This may be a maintenance problem / defective unit, or it may be a fundamental limitation of the algorithm.

The machine displays where it's sensing with triangles, so that the medic can visually confirm that it's sensing appropriately. In this case, the medic either chose not to do this, or did it carelessly, and assumed the machine had sensed correctly.

The appropriate action, had they determined that the sensing was inappropriate would be to select another lead, and see if that improved matters.

Are the machines designed to work off of Lead II and provide a multiplicity of choices? Does the medic have to choose which one to "go for"?

The medic can choose. The machine is usually fairly reliable, but as illustrated here, has its moments.

Is that a defective machine? (the monitor, not the medic!)

Maybe, maybe not. It would be interesting to know.

What do other users of that make and model need to know so this doesn't happen again.

Assuming that the machine is working correctly, they need to be more diligent in checking that the machine is correctly labelling the R waves.

This "oversensing" can sometimes be a problem in implanted pacemakers, or AICDs.

 

[Aidey]

Just because it is suspicious for V Tach doesn't mean it is V Tach. When you look at the rhythm present right after the v-fib it is obvious that the QRS is still wide, the T waves are still peaked and there is still discordance.

 

[systemet]

Just because it is suspicious for V Tach doesn't mean it is V Tach.

Agreed. I can appreciate the argument that there may be F waves in aVR. But VT seems a strong possibility, and I don't think that the 3 lead or the pre-12-lead really paint a picture where treating this as VT is wildly inappropriate.

When you look at the rhythm present right after the v-fib it is obvious that the QRS is still wide, the T waves are still peaked and there is still discordance.

True, but we're also looking in paddles at 0.5-30 Hz, probably at lead II, in a stunned heart.

When I referred to negative precordial concordance, what I meant was that, in V1-V6, the complexes were all negatively deflected.

 

[Aidey]

Its ST with a LBBB. Most likely with elevated potassium.

You've got RS complex present in V5 and V6 - Favors an SVT over VT.
The QRS complexes in V1-V6 appear to all be under 100msc - Favors an SVT over VT.
There is no evidence of ectopy or fusion beats - Favors an SVT over VT.
There is no slurred or notched S wave in V1 or V2 - Favors an SVT over VT.
No Q waves in V6 - Favors an SVT over VT.


Also concordance and discordance refer to the direction of the QRS vs the direction of the T wave. Concordance means they are both going in the same direction. Discordance means they are going in opposite direction. The term you are looking for is "deflection". The percordial leads have a negative deflection.

 

[Christopher]

Also concordance and discordance refer to the direction of the QRS vs the direction of the T wave. Concordance means they are both going in the same direction. Discordance means they are going in opposite direction. The term you are looking for is "deflection". The percordial leads have a negative deflection.

In the case of SVT versus VT, the phrase "positive concordance" and "negative concordance" is referring to the polarity/deflection of the complexes, not the QRS/T-wave axis relationship.

 

[Aidey]

Interesting. I have never in any EKG lecture heard it different than what I posted. It may be that our Doc is just simplifying it to avoid confusion.

 

[Christopher]

Interesting. I have never in any EKG lecture heard it different than what I posted. It may be that our Doc is just simplifying it to avoid confusion.

This use/abuse of the term is limited to the discussion of VT versus SVT, but I understand your confusion. It is a relatively specific finding for VT which I've covered in a blog post detailing why its absence does not rule-out VT (not the case here).

 

[systemet]

In the case of SVT versus VT, the phrase "positive concordance" and "negative concordance" is referring to the polarity/deflection of the complexes, not the QRS/T-wave axis relationship.

Although it looks like I'm in error here, and we don't have negative precordial concordance, As this would require the presence of QS complexes throughout the precordial leads. The rS complexes in at least V5-V6 (and possibly V3, V4) make this impossible.

Somehow I'd turned QS waves throughout the precordium into "predominantly negative complexes across the precordium" in my head. My fault.

Were we to have negative precordial concordance it would be highly specific for VT.

 

[systemet]

You've got RS complex present in V5 and V6 - Favors an SVT over VT.

Yes.

The QRS complexes in V1-V6 appear to all be under 100msc - Favors an SVT over VT.

Maybe. Depends on where you put the J point.

There is no evidence of ectopy or fusion beats - Favors an SVT over VT.

True, but very insensitive, especially off a 10 second strip.

There is no slurred or notched S wave in V1 or V2 - Favors an SVT over VT.

Well, V2 looks notched to me, but I agree that there's a rapid downstroke to the nadir of the S wave, and no classic Josephson's sign.

No Q waves in V6 - Favors an SVT over VT.

Yep.

You make a good case, and you're probably right, and I'm probably wrong. But I think I'd still be reluctant to give metoprolol or diltiazem here. These are difficult judgments to make in the field.

 

[TomB]

Who says it requires QS complexes across the precordium?

Although it looks like I'm in error here, and we don't have negative precordial concordance, As this would require the presence of QS complexes throughout the precordial leads. The rS complexes in at least V5-V6 (and possibly V3, V4) make this impossible.

Somehow I'd turned QS waves throughout the precordium into "predominantly negative complexes across the precordium" in my head. My fault.

Were we to have negative precordial concordance it would be highly specific for VT.

 

[Aidey]

I don't think anyone is arguing for advanced pharmaceutical intervention at this point. As someone mentioned a fluid bolus would be one place to start. Since this is a dialysis pt we have the potential for some very whacky electrolyte levels contributing to this.

 

[systemet]

Who says it requires QS complexes across the precordium?

Perhaps a better way for me to have put it is "the absence of RS complexes across the precordium".

(Kusumoto, ECG Interpretation: From pathophysiology to clinical application, googlebooks: http://books.google.ca/books?id=wQ6...Bw#v=onepage&q=precordial concordance&f=false)

For what it's worth, I've read other sources that seem to contradict this. Most of my books are in a storage container waiting to be shipped right now.

Also descibed on p.455, Irwin & Rippe's Intensive Care Manual, here: http://books.google.ca/books?id=ooH...v=onepage&q=precordial concordance RS&f=false