# Tachy arrythmia Obscured by Pre-existing left bundle branch block?



## mrhunt (Jul 5, 2021)

Hey, so this was a tricky one for me so figured would be good to post it here and get some more feedback!

50yo M,  A&0X4. Sitting in chair complaining of difficulty breathing that was exaccerbated by going out to his garage with physical exertion. History of asthma and hypertension. He's satting 88% RA, Skins are Very diaphoretic but its also 110 degree's outside at the time. He's in moderate resp distress at about 25 resp and slightly labored.  

No chest pain, nausea, vomiting, weakness, dizziness, confusion, syncope or any other complaints. He denies any cardiac history whatsoever aside from asthma and hypertension (i SUPPOSE you could say thats cardiac? but splitting hairs in a way......i digress)

Get him on monitor and 4 lead is showing a sorta bigeminy ranging between 130's to 200's and just all over the place. Im thinking AFIB RVR new onset possibly.  We get out to the rig and 12 lead Is Left bundle branch block but tachy as **** still ranging between 130's to 200's.......200's isnt sustained and only briefly stays there and he's more on the lower end.   Lungs are pretty clear, VERY minimal wheezing so i do a duoneb just to rule it out. Get IV enroute. 

The duoneb actually somewhat improved his resp status with SP02 now at 95%, resp rate to about 20 and minimally to not labored anymore. 
BP 150's systolic (hypertension history) 

We go Code 3 to hospital and transport time is less than 3 minutes.  Hospital almost immediately hits him with adenosine...... No change. 
I left after that but they were talking about cardioversion.


I hesitated a bit because how am i gonna Adenosine someone with a Wide complex rhythm that appears left bundle branch block? Lidocain is in our protocols for a wide complex but again....With his rate jumping all over the place im thinking there's an underlying rhythm such as Afib rvr Or something else that i cant see?


What would you guys have done differently? 
(ps i'll try to attach the 12 lead soon. but its basically just a left bundle branch block at a rate of 131bpm)


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## theruralmedic (Jul 5, 2021)

1. Patient is not unstable so attempting to cardiovert (electrical or pharmacological) wouldn't have been on my list of treatments.

2. Lungs are clear with minimal weezing I'd would have held off on the duoneb and just tried some supplemental oxygen first as the albutorol would cause tachycardia.

3. IV fluids, supplemental O2, cooling, and transport. If things didn't improve from there I'd consider more invasive options at that point.

Did his palpated pulse match what you were seeing in the 200 range or was that potential artifact?

Adenosine is indicated in wide complex as a potential treatment however if you could have identified RVR would you have cardioverted or not is the question. In my opinion unless vitals are heading the wrong direction I wouldn't cardiovert. The body is trying to compensate for something and I don't think it's a conduction issue.


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## E tank (Jul 5, 2021)

I would have just tried adenosine. The picture you paint is low threshold for supraventricular and he's stable.  Wouldn't have given a neb as the lungs were clear and the HR is fast enough already. O2 and some fluid.


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## Tigger (Jul 5, 2021)

Gotta have an EKG to make any sort of comment.


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## mrhunt (Jul 6, 2021)

So Fluid wouldnt have HURT but that wasnt the main problem likely , but a heatstroke / dehydration thing wasnt a concern.  Pt stated he was in the garage BRIEFLY and then went back into cool home.  It appeared enough to cause asthma exacerbation but that was about all. 

Pt was placed on nasal cannula @ 4lpm on scene due to 88% RA with improvement. 

And again, The ER immediately used full dose of adenosine but was unsuccessful. Pt clearly had an underlying rhythm but Neither myself, The ER doc or any of the nurses knew what it was.  Even one of the nurses was like "he's got SOME type of rhythm! Either svt or V-tach sorta thing.... dunno"


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## Aprz (Jul 8, 2021)

This post would be a lot more interesting with a 12-lead. :]


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## mrhunt (Jul 8, 2021)

Here we go.


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## Aprz (Jul 8, 2021)

Great 12-lead! Thank you for sharing.

I am usually very suspicious when there is a lot of right axis deviation because the most common cause of that is right and left arm lead reversal. Usually it is beneficial to see a P wave because it would be negative as well in right and left arm lead reversal. Unfortunately, I don't see any definitive P-wave.

Right axis deviation with a left bundle branch block (LBBB) would be a very atypical feature. This is because the left side of the heart is last to depolarize due to the left bundle branch block and this usually actually causes left axis deviation. Although the precordial leads have LBBB-morphology, the frontal leads (limb and augments) do not. A typical LBBB would have left axis deviation (tall R wave in lead I, S waves in the inferior leads II, III, and aVF). Sometimes it has normal axis with an upright R wave in lead I and aVF. This is the opposite with a deep S wave in lead I a small RS in lead II and R waves in lead III and aVF. Lead II is so small because the mean QRS vector is perpendicular to it, both sides are almost equally negative and positive, making the mean QRS vector +150 degrees. That's also why aVF and aVR are small leads, because tehy are just 30 degrees away from being perpendicular. It's almost perpendicular to lead aVF and aVR, almost. Lead aVL should be the biggest, if we could see the nadir, because it travels along the same pathway as aVL in the opposite direction of the positive lead.

Personally, I don't see irregularity. In my eyes, the R-R interval remains the same at a rate of 136 bpm. Of course, when the rate is fast like this, irregular rhythms can look regular and maybe you just happened to capture a moment of regularity. *shrug* I'm not sure if you were confirming as well that the monitor wasn't being tricked into thinking that T waves were QRS, which happened a lot with my monitors. If you were monitoring lead II, the one with the poorest view of the QRS complex due to being perpendicular to the mean QRS vector, the monitor would've easily been fooled into mixing up the QRS and T waves and falsely report a higher heart rate.

To me, it somewhat looks wide-ish for typical LBBB as well. It looks like about 4 mm or 160 ms.

Based on this 12-lead alone, assuming no right and left arm lead reversal, *I would've been thinking ventricular tachycardia* just because it is a wide complex tachycardia, no definitive P waves, looks regular to me, and the right axis deviation being atypical for a LBBB.

Can you get follow up from the hospital? I am definitely interested.


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## Tigger (Jul 9, 2021)

This is a good one. As shown I think this to be Vtach, although the nadir in V1 is maybe less suggestive of that. Right axis, no p waves, wide, and pretty regular appearing. I think @Aprz's point about the monitor counting the T waves as the rate is well taken, and it won't necessarily count _every_ T wave which would explain a calculated irregular rate. 

I dunno what I would have done here. Probably tried just some O2 by NC to avoid giving a rate increase drug unless the patient appeared to be quite symptomatic from asthma, which does not sound to be the case. Get a line, get some fluid running, and if things get much worse I'd probably sedate and cardiovert him. Much of his symptoms could be from being in Vtach.


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