A patient with chest discomfort and wide QRS tachycardia: VT or not VT? by Dr. Bojana Uzelac


This ECG case was posted in FB ECG Rhythms page on - 10.29.15 - https://www.facebook.com/ecgrhythms/posts/629361277166523

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Vignette:
(Courtesy of Dr Milena Popovic) This is ECG is from 80 yo woman complaining of chest discomfort and palpitations for one hour. She is hemodynamically stable at the moment of examination. No previous ECGs are available to compare. What do you think about rhythm here: VT or SVT?

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Thank you all for such interesting discussion!

This was a case of wide complex tachycardia (WCT) rate about 140/min; actually, this was atrial flutter 2:1 conduction with left bundle branch block (LBBB).

As I mentioned in my comments on ECG Rhythms page and in the FB Group EKG club, this woman was admitted to a hospital because of acute coronary syndrome (ACS). Initially in ED, she had chest discomfort and palpitations. While waiting for her lab results, physicians tried to decrease her heart rate with labetalol IV (Presolol). Although she stayed hemodynamically stable, Presolol didn’t work and her symptoms didn’t improve. Her Troponin level came back highly elevated 10,3ng/dl, and she was hospitalized as an ACS. In the hospital, they were worried that this WCT could actually be VT. So, they gave her Amiodarone in attempt to convert her. That worked and she was successfully converted into sinus rhythm (Picture 1).


Picture 1. 12 Lead ECG post-conversion

As you can see this is sinus rhythm with LBBB morphology, rate about 96/min. PR interval is borderline for AV block 1st degree: 0.20 sec but the most important fact: the QRS morphology during sinus rhythm match with the QRS morphology during WCT, meaning that origin of WCT is supraventricular.

Our patient is still in the hospital and she is doing well.  

So, what would be correct approach to patients like this? 

The initial rhythm is very similar to VT. As Ken Grauer mentioned in his comment in EKG club, reasons why should we suspect VT are:  i) The QRS is all negative in lead III; ii) the initial slope of the downslope of the S in V1 is slow (and not steep as would suggest lbbb aberration); and iii) there is a fat initial R wave in V2 (makes SVT less likely); and iv) VT is MUCH more likely than SVT with aberration in an 80 yo.

The smartest thing for a PROVIDER to do and the safest for PATIENT is to treat this rhythm as VT until proven otherwise! Remember, 80% of WCTs are VTs!

But, some findings on our first ECG are revealing that this tachycardia is supraventricular in origin. In leads V1-V3, there are clearly visible blips preceding every QRS. These blips are small and so close to QRS that make pseudo R waves in lead V1. Another blip is hidden and (as Chandran Pv said in his comment in EKG club) there is also notching at the beginning of ST segment, indicating atrial activity in addition to the visible blips. Atrial rate in this case is about 280/min. That makes AV conduction ratio of 2:1.


Picture 2. Atrial activity is shown with red lines. Green circles are for visible waves and blue arrows indicate a place of hidden blips.

If you are suspicious about my theory of hidden flutter waves, you could name this rhythm as sinus tachycardia. In other words, only visible P waves in green circles are recognized as atrial activity.

Let us compare leads V1-V3 during WCT and during sinus rhythm.


Picture 3. Leads V1-V3 during tachycardia and in sinus rhythm showing significant differences. 

There are distortions in the ST segments in leads V1-V3 (notching at the beginning as shown by blue arrows) during WCT, while after conversion these blips are gone. ST segment in sinus rhythm is smooth (blue lines).

Pseudo R waves in lead V1 as I’ve mentioned before are labeled with green circle in picture 3. These blips disappeared during sinus rhythm; instead there is QS with smooth initial part (green lines).

Shape and amplitude of atrial activity waves are not same in these two rhythms: P' s are more prominent (rounded and bigger as shown in purple arrows) during sinus rhythm.

PR intervals are significantly different: the longer ones are during sinus rhythm (labeled with red lines).  

Facts above should prove that rhythm from left side of picture 3. is not sinus tachycardia.


Picture 4. Inferior leads during WCT are showing saw-tooth shape suggesting atrial flutter. On contrary, P waves are clearly visible in sinus rhythm (red circles).

Inferior leads (especially lead II) are showing saw-tooth shape during tachycardia. After conversion there are distinct P waves preceding every QRS.
Take home point once again: WCT associated with ACS is VT until proven otherwise. And in practice, it usually turns out to be VT.


This case was a rare example of supraventricular origin of WCT in patient with ACS. But remember, this is an exception! 

3 comments:

  1. VERY NICE write-up of this case by Bojana Uzelac. I have always found it highly instructive (if not downright humbling) when something turns out different than expected to GO BACK and review the case once more is known.

    The 1st Lesson for ME about this case — is the humbling reminder that quick iPad review when traveling on-the-road is no substitute for more careful assessment of a better resolution tracing — and, in the case of problematic tachycardias — iPad review is no substitute for the use of CALIPERS … On returning home, I brought up this tracing on a much better resolution larger screen — and now having access to calipers, it became immediately obvious that the original tracing shows CLEAR evidence of “extra P wave deflections” (best seen in V1,V2) that perfectly march out at precisely twice the ventricular rate of 140/minute = 280/minute. So, regular atrial activity at ~280/minute should strongly suggest AFlutter as the initial diagnosis. This is all WELL described by Bojana in her write-up.

    I’ll take this opportunity to emphasize the key points brought up by Bojana’s case. My original assessment = “This is a regular WCT ( = Wide-Complex Tachycardia) at ~140/minute without clear evidence of sinus P waves” still HOLDS TRUE. All too often interpreters feel the need for MORE precision than is possible from a single tracing. So even though extra blips now embarrassingly evident to me on this tracing should strongly suggest AFlutter — we still have a WCT rhythm, and we should continue striving until we are 100% certain for the reason the QRS is wide. Finding an old tracing with LBBB during sinus rhythm would be optimal (Was there ANY prior ECG available on this patient at the time they presented with tachycardia?). Alternatively — Bojana showed us the post-conversion ECG once sinus rhythm was restored, and THAT confirmed underlying LBBB. But, until such time as a supraventricular etiology is proved — I think ( = my opinion) that optimal description of this rhythm is not "arial flutter" — but rather remains that of a regular WCT at ~140/minute without sinus P waves that is probably AFlutter given perfectly regular extra deflections at 280/minute in V1,V2. I realize the difference may seem semantic — but premature "closure" on a diagnosis before certainty is attained is a reason subtle findings can be missed.

    There can be “confounders”. Cases of VT occurring in association with underlying atrial flutter HAVE been reported. Against that in this case, is that the relationship (ie, PR or F-R interval) preceding each QRS complex is constant — whereas simultaneous existence of VT and AFlutter would be expected to show AV dissociation and no regular interval between flutter waves and neighboring QRS complexes.

    Finally — there remains the issue of chest pain and the markedly positive troponin (elevated much more than one would expect for the slight troponin elevations commonly seen with sustained tachyarrhythmias). I would have liked to see at least one more 12-lead ECG (and of a better resolution than on this blog) taken after restoration of sinus rhythm. While I don’t see primary ST elevation on this sinus rhythm LBBB tracing (Picture 1) — the SHAPE of the ST depression in V4,V5 is not as expected for simple LBBB — and the amount of J-point ST depression in neighboring lead V6 looks excessive — so these look like primary ST-T wave abnormalities in the setting of underlying LBBB … Was the patient taken to the cath lab?

    THANK YOU once again Bojana for your great discussion!

    BOTTOM LINE: AFlutter remains the most commonly overlooked diagnosis for SVT rhythms. Best ways not to overlook this rhythm diagnosis is to strongly suspect it in any SVT rhythm with a ventricular rate close to 150/minute (ie, 140-160/minute range) — in which case especially careful search for atrial activity (using calipers) will often reveal extra deflections — that can then be confirmed by subsequent measures.

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  2. Thanks for your comment, Ken! I always appreciate it. :) About this patient: she is still in the hospital and she is doing well for now. I didn’t see her cath lab results yet, but I’ll try to get them. Also, I’m going to ask colleges for another ECG in sinus rhythm.
    And about this rhythm, my point (and the rule I’m using in my clinical practice) is to be very, very careful about declaring some WCT for supraventricular in origin. In majority cases (especially elderly, previous CD or acute CP patients), I feel absolutely comfortable to treat them like VT rather than agonized about they origin.

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  3. Your approach is excellent Bojana — :)

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