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Spontaneously Changing Conduction In Wide Complex Tachycardia

Submitted by Dawn on Wed, 04/10/2013 - 22:23

This ECG was donated to the ECG Guru by Dr. Arnel Carmona, one of our favorite Gurus. You will not often see such a great example of this. We are very grateful to Dr. Carmona for his contribution to learning. Dr. Carmona's new blog is EZG - ECG for beginners and enthusiasts.

An adult patient was admitted due to palpitations. What is this rhythm?This is a tachyarrhythmia that initially is regular wide complex (RBB morphology) and later became regular narrow complex at a rate of about 187 bpm. There is normalization of the QRS without a change in heart rate. In the latter part of the tracing (narrow complex), pseudo-r can be seen in V1. So, this is SVT with aberrancy with spontaneous normalization.

What is the cause of the intraventricular aberration during acceleration of heart rate? It could be due to failure of the refractory period to shorten or possible lengthening in response to acceleration.

What is the cause of the normalization of the of the QRS? The normalization of intraventricular conduction could be due to the gradual shortening of bundle branch refractory period in response to the tachycardia.

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Wide Complex Tachycardia: V Tach

Submitted by Dawn on Sat, 06/02/2012 - 14:02

This wide complex tachycardia occurred in a 91 year old man with a history of atrial fibrillation. He complained of "fluttering" in his chest, and denied chest pain or other problems. While the paramedic attempted to start an I.V., he spontaneously converted to atrial fibrillation with left BBB, and PVCs. Once he converted, his symptoms abated. Remember, all wide complex tachycardias (WCT) should be treated as V Tach in the field, as this is by far the most common WTC and the most dangerous.

Some of the ECG clues that this WTC is ventricular tachycardia are:

* Monophasic upright QRS in V1 (does not have RBBB pattern of rsR')

* Extreme left axis deviation (II, III, and aVF are negative, I, aVL, and aVR are poisitive)

* V6 is negative

For a more thorough discussion of the ECG signs of V Tach, go to Jason Roediger's Ask the Expert page discussion on the topic:

http://www.ekgguru.com/node/157

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Wide Complex Tachycardia in a Patient with WPW

Submitted by Dawn on Mon, 03/12/2012 - 16:03

This ECG was submitted by Sebastian Garay, EMT-P and ECG Guru (and ECG Guru Member sebmedic). It is a very interesting case of wide complex tachycardia in a patient with Wolff-Parkinson-White.

This is from a 57 year old man who sought medical help for a complaint of palpitations. He was known to have WPW. The paramedics determined that he was hemodynamically unstable, and in light of the wide-complex tachycardia, they performed a synchronized cardioversion at 100 j. The patient converted to the rhythm shown in the next ECG. The paramedics then administered a Lidocaine bolus and drip, considering this to be a ventricular tachycardia. The patient arrived in the Emergency Dept in improved hemodynamic condition.

This ECG can be used to teach V Tach for beginner students, WPW and WCT tachycardia differential diagnosis for more advanced students. It is also a good ECG for axis discussion, and for how lead placement affects the final product.

The differential diagnosis here is 1) V Tach and 2) SVT with aberrant conduction or left ventricular conduction delay. For a discussion of ECG criteria which help us diagnose WCT, see the "Ask The Expert" column from Jan. 11, 2012. Characteristics that make this look like V Tach include: wide complex and significant left axis deviation. Features which may favor a diagnosis of SVT are the pre-existing WPW and a rate of 222/min. There are no p waves seen. NOTE: V2 in this ECG appears to reflect electrode mis-placement, as it does not "make sense" in the normal progression of the QRS complexes in the precordial leads. It is clearly "out of place".

The second ECG shows the same patient after conversion of the tachycardia. The delta waves of WPW are easily seen.

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Wide Complex Tachycardia, 12 Lead ECG and Rhythm Strip

Submitted by Dawn on Wed, 11/30/2011 - 13:22

This is a good example of wide complex tachycardia that must be evaluated for V Tach vs supraventricular rhythm with left BBB.

There is an irregular rhythm. When the rate is fast, it is important to look at a longer strip, as sometimes fast rates will cause the rhythm to look regular. We know that monomorphic V Tach is not irregular, so that tells us that we are looking at atrial fibrillation.

The ECG criteria for left bundle branch block is met here: 1) supraventricular rhythm (atrial fib), 2) wide QRS, and 3) negative QRS in V1 and positive QRS in Leads V6 and I.

With wide complex tachycardia, there is always a chance of ventricular tachycardia, and the patient should be treated as V tach until proven differently. For more on determining whether a WCT is V tach or SVT with ventricular conduction delay, go to this LINK.

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Wide Complex Tachycardia: Left Bundle Branch Block

Submitted by Dawn on Wed, 11/30/2011 - 13:03

Today, we are revisiting an ECG from the archives, with a NEW comment from Dr Ken Grauer. This ECG is worth a second look because it is a very good example of the left bundle branch block pattern. It's also a good ECG to use when discussing treatment of wide-QRS tachycardias.

This ECG demonstrates a wide complex tachycardia with classic signs of LBBB: wide QRS, QRS negative in V1 and positive in V6 and Lead I, and supraventricular rhythm. P waves are difficult, if not impossible, to discern for sure. The machine does give a P wave axis and PR interval. When evaluating a wide complex tachycardia, the patient's hemodynamic stability will initially determine treatment. All WCTs should be treated as V TACH until proven otherwise. The presence of a typical LBBB pattern makes LBBB very likely, but is not a sure thing. This patient was confirmed to have LBBB when the rate slowed, the P waves became visible, and the QRS complexes did not change.