Wednesday, June 14, 2017

An adolescent with trauma, chest pain, and a wide complex rhythm

This case was sent by Dr Avinash Krishnamurthy, a fine emergency medicine resident from Australia Cairns base hospital


An adolescent male had a mechanical fall and injured his left shoulder and arm.  There was apparently no syncope and he had no bony injuries, but he did complain of left sided chest pain.  His chest was tender.  A bedside cardiac ultrasound was normal.

An ECG was recorded:
Avinash was understandably confused by this ECG.
He wrote:
"ECG 1 - shows wide ???IVCD type rhythm ?? Delta waves in them and then his native rhythm, with ectopic pace maker??"

This was recorded shortly after:
"Wide complex rhythm"

This was recored seconds later:
QRS are normal. P-waves are inverted with normal PR interval.  This is low atrial rhythm.

Here is my response:

The QRS morphology looks like WPW, but it can't be because there are no P-waves, and when P-waves do appear, the QRS normalizes.
I think this is accelerated idioventricular rhythm, but with a slightly strange QRS.

Accelerated idioventricular rhythm is a generally benign rhythm. It is commonly seen in the reperfusion setting.  It appears to be benign in children as well (see references below).

I sent it to my friend, Ken Grauer, who is very meticulous in his ECG reading.  He has a great blog too: ECG Interpretation

He is also well known on the Facebook EKG Club page, where you can learn tons about ECGs:

Here is his response, with the first ECG labelled:

Hello Steve & Avinash.

I agree completely with Steve — that this is AIVR with a strange-looking QRS complex. I labeled ECG. As we see in ECG #3  — the regular rhythm is NOT sinus, because the P wave is negative in lead II. The P wave is positive in lead aVL of ECG #3, which means it is a low atrial (or probably coronary sinus) rhythm — which of itself is not necessarily “abnormal” in a child if there is no other sign of underlying heart disease. 

So if we now come back to ECG #1 (directly below what I’m writing) — we can see this low atrial rhythm resume for beats #10,11,12 at the end of the tracing. The first 8 beats are AIVR — and beat #9 is a FUSION beat. You can see in simultaneously obtained lead V2 for beat #9 that this beat IS wider than the low atrial beats that followbut NOT quite as wide as beats #7 and 8 in lead V2. This makes sense, because the PR interval preceding beat #9 in the long lead II at the bottom is slightly SHORTER than the PR interval of the normally conducted low atrial beats (#10,11,12). This PROVES ventricular etiology for wide beats #1-thru-8. Sometimes (depending on the site of the ventricular rhythm) you may see initial slurring in the QRS that in some leads resembles a delta wave — but the rhythm here is AIVR.

In ECG #2 — we see the REASON why this slightly accelerated ventricular rhythm was able to “take over” — namely that there is a slight slowing of the rhythm after the 1st beat in the long lead II of ECG #2, just enough to allow the slightly accelerated ventricular rhythm to take over! 

In ECG #3, the low atrial rhythm rate becomes slight faster than the AIVR rhythm — so that’s why it again takes over.

AIVR is NOT common in otherwise healthy children. I’ve attached an article and an abstract (that article is in Japanese unfortunately … ) that do document that you CAN however on occasion find AIVR in otherwise healthy children — and I suppose that IS what we have here. Perhaps the circumstances surrounding the ED visit cause slight acceleration in the ventricular escape rate to allow this all to happen.

Here the full text of the article:

Hope that helps!

: ) Ken

Case Outcome:

The patient had never had any cardiopulmonary complaints, was otherwise completely healthy. He was admitted overnight and had no complications.  He was discharged and schedule for an outpatient echo which has not been done yet.

More literature on this:

Here are other examples of Accelerated Idioventricular Rhythm, Usually a Reperfusion "Dysrhythmia"

I saw this on the computer. Most physicians, at first glance, get this wrong. What is it?

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