Discussion to 60 year old male CC: "I don't feel well"

This is the discussion for 60 year old male CC: "I don't feel well".

Go back and familiarize yourself with the history and clinical presentation because it's important to the case (as it always is).

Here is the rhythm strip and 12-lead ECG that was presented.

You may recall from my series on ineffective or inappropriate ICD shocks rhythm analysis for patients with an implantable cardioverter-defibrillator can be challenging.

That's because patients with sick hearts often suffer from both atrial fibrillation and bundle branch blocks which predisposes them to "wide and fast" rhythms.

If you've taken nothing else away from the EMS 12-Lead blog I hope you've taken away the message that "wide and fast" is VT until proven otherwise! 

Granted, irregular wide and fast rhythms are a special case. In the first place you avoid adenosine according to the 2010 AHA ECC Guidelines. That's because atrial fibrillation is unlikely to respond to adenosine, not to mention that giving adenosine to a patient with WPW and atrial fibrillation can precipitate VF.

So let's look at the differential diagnosis of the wide complex tachycaria.

Could it be VT?

Sure. It's rare for VT to be irregular but it's certainly not impossible. We need to remember that the patient has received an ICD so one assumes the patient is at high risk for malignant ventricular arrhythmias. "But the axis is normal!" you might say. Yes, but as I've mentioned so many times before, it's an EMS myth that VT always shows an extreme axis deviation. In fact, LBBB in lead V1 with a normal frontal plane axis is normal for VT orignating in the right ventricular outflow tract.

Could it be AF with LBBB and RVR?

Yes. This is entirely possible. Quite often irregular wide complex tachycardias turn out to be AF with RBBB, LBBB, or nonspecific IVCD. It's a bit unusual but certainly not impossible for LBBB to show a normal frontal plane axis.

So, if it could be either VT or "SVT" (a term I don't care for) with aberrancy (or preexisting bundle branch block) then how should we treat the patient? Should we treat the patient at all?

When faced with a situation like this I think it's far more important to "risk stratify" the tachycardia rather than "diagnose" it. In other words, remember the first rule of medicine: "Do No Harm!"

Above all else, avoid IV medications that could kill the patient if it turns out to be VT.

So why isn't the ICD shocking? Because the rate isn't fast enough. It's not unusual at all for patients with an ICD to present with a wide complex tachycardia below the rate limit that initiates cardioversion or defibrillation.

So what else happened in this case?

En route to the hospital an additional 12-lead ECG was captured and several more rhythm strips.

This 12-lead ECG reveals an important problem with prehospital 12-lead ECGs. They often crop the S-wave, especially in the right precordial leads (V1-V3) which can makes it impossible to compare the ST-segments to the depth of the S-waves (rule of proportionality).

The patient was delivered to the emergency department where the following 12-lead ECG was taken.

Now we can see the depth of the S-waves in leads V1-V3 and there's a problem (beyond the fact that the precordial leads have been placed differently on the patient's chest).

If this is a left bundle branch block then excessively discordant ST-elevation is present in leads V2 and V3 which indicates acute STEMI.

So what was the outcome?

All we know for certain is that the patient received successful synchronized cardioversion in the emergency department. The paramedic who submitted the case was told by the RN in the emergency department that the QRS complexes were narrow after the cardioversion (which would support a ventricular origin). However, we don't have a post-cardioversion 12-lead ECG to confirm.

We also don't know whether or not the patient ruled-in for AMI. But I certainly wouldn't be surprised! 

9 Comments

  • VinceD says:

    Jeebus that's some excessive discordance. I've been checking this case daily for follow-up since it was first posted, so it's nice to see at least partial resolution. As always, an interesting case with a very useful discussion, thanks Tom.

  • Nina says:

    You wouldn't by chance know of a web site that has a variety of cardiac strips to practice interpreting them? I'm halfway into getting a monitor tech job and the more I can thoroughly identify blocks increases my chances of landing this job

  • Nick Adams says:

    Yes I do Nina, http://ecg.bidmc.harvard.edu/maven/mavenmain.asp. Have fun.
    Tom, I know at times that a VT can be irregular (slightly). But in this case, I would call this an A-Fib with RVR and a LBBB. A couple of reasons: Rhythm is irregularly irregular, normal axis (not definitive), QRS morphology in V1 (being negative) supports a LBBB and not VT (no fat r-wave, QS notching or slurring).  No concordance in the precordial leads, and a positive V6.  I would assume that after cardioversion, with the resolution of the LBBB morphology and wide QRS, could indicate VT, but I would like to know the post-cardio version sinus rate.  If the rate was slower post cardioversion, this could indicate a rate dependant LBBB and not VT.
    I would totally agree that this is extremely suspicious for an Anterial wall MI with the excessive discordant ST segment elevation in V2 and V3.  I'd also point out that V4 is also showing signs of ST segment elevation. 
    I guess if the patient really needed prehospital medication treatment, the safest drug to use would be Amiodarone because it could effectively treat a rapid A-Fib or VT.
    Am I wrong to say?
    Respectfully,
    Nick Adams

  • I agree with amiodarone over a CCB but it simply isn't true that LBBB morphology in lead V1 points away from VT or that lack of concordance in the precordial leads rules-out VT. I'm not saying this rhythm isn't AF with LBBB. I'm saying that I look at these situations through the lens of risk stratification.

  • Tom,
    Great case!!
    I wouldn't say that a narrow complex after cardioversion necessarily supports ventricular origin.  Rate-related LBBB is very common.  My guess due to the irregularity is that it was atrial fib with RVR and rate-related LBBB, and sure looks like LAD occlusion with that disproportionally discordant ST elevation.
    Steve Smith

  • Nick Adams says:

    I totally agree with Steve. 
    Tom – It would have been much easier to call this VT if the rhythm was more regular with ERAD, and a positive V1 with a negative V6….lol.  I'd just like to make it clear about what I meant when I said that V1 was negative.  I meant that a negative complex in V1…….WITH an absent (fat R-wave), (QS nothching), or (QS slurring) is no help with diagnosing this as VT.  The absence of concordance is also not a determining factor.  I'm just saying that an irregularly/irregular rhythm, no ERAD, morphology of the QRS in V1 (not BBB morphology), no concordance, and a positive V6 are no help in calling this VT.  I have a 12-lead of a patient who was in a, more regular, wide complex tachycardia which did not meet any of the VT 12 lead criteria (like this one).  He was treated with Lidocaine without success, and then treated with Amio which slowed the rhythm to show an A-Fib with a preexhisting LBBB (very cool).  I've found that rapid a-fib at high ventricular rates can be extremely regular.
    Reguardless, any patient who is to be treated with medicine with a wide complex tachycardia, should be treated with Amiodarone (Procainemide for WPW).  We'll save the Cardizem for the narrow complex irregular tachycardias…….lol

  • Deborah Adams says:

    Hello. I am new to this site. I am a paramedic student & we are just learning to read & interpret ECG strips. I love how informative this site is & I appreciate all the actual pics of the ECG's. I was going over this particular case & it is so interesting to me & I was wondering what would be the easiest way for me to learn more about ECG strips & interpreting them & info on the heart to help me in my class?

  • Deb says:

    RVOT VT would explain why DCCV works!

  • S. Carter says:

    Tom or Dr. Smith,
    Is there any literature out there that suggests coronary artery involvement when Sgarbossa's Criteria is used?  I can't find any and if there is I would like to pass it along to my students.

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