Bedside to Bench

Arrhythmia Grand Rounds, April 2015, Volume 1, Issue 1: 38-41
DOI: 10.12945/j.agr.2015.00021-14

Bedside to Bench – A Difficult Journey: An Irregular Wide QRS Tachycardia

Negar Salehi, MD, Aravdeep S. Jhand, MD, Vaibhav Satija, MD, Watchara Lohawijarn, MD, Ranjan K. Thakur, MD, MPH

Sparrow Thoracic and Cardiovascular Institute, Michigan State University, Lansing, MI, USA

Abstract

A 40 year old man presented with palpitations and was found to have a sustained, monomorphic, irregular wide QRS tachycardia. He had a history of sarcoidosis, based on muscle biopsy. Cardiac MRI, PET scan and electrophysiology study were normal. Potential mechanisms of this tachycardia are discussed.

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Paul Levine — Oct 13, 2015 3:58 PM
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I was struck by the periods of group beating in the monomorphic tachycardia shown by … et al (1). In 1976, I had the privilege of attending a 5 ½ day course at Michael Reese Hospital in Chicago by Drs. Alfred Pick and Richard Langendorf. On the last afternoon of the course, they presented an arrhythmia similar to this but at a slower rate where they indicated the potential diagnoses were either Wenckebach exit block out of an ectopic focus or dual pathways out of that same focus, similar to the case by Josephson (2) presented in this issue of the AGR. The next morning, they came into the lecture hall with a report that when they returned to their office after the course the previous day, they found a letter from Dr. Gordon Moe reporting an isolated tissue preparation in which Dr. Moe demonstrated both 2nd degree Wenckebach exit block and dual pathways out of the same tissue to result in a monomorphic rhythm with grouped beating. I captured the image from Figure 2 and attempted to laddergram it. There is the ectopic focus, the peri-ectopic focus tissue and then the rest of the ventricular activation. This analysis would suggest an extremely rapid ventricular tachycardia (grid marks were not available in the published article) with a Wenckebach exit block out of the VT focus. At time, there are two levels of AV block out of the focus similar to what one might encounter in the AV node in Atrial Flutter with a 5:2 pattern. The presumptive VT rate is identified by the series of closely spaced QRS complexes. If one, using calipers continues to march this rate through the tracing, one can laddergram a Wenckebach pattern, both 3:2 and lower grades of Wenckebach exit block. Although the above mechanism is hypothetical, it also raises the issue of a very rapid ventricular tachycardia occurring spontaneously. Without a definitive etiology that can be addressed and without a sufficient frequency to know if it will respond to pharmacologic therapy, was an EP study performed in an attempt to reproduce this rhythm (although the anticipated inducibility is expected to be low)? How is this patient being managed at this time? Paul A. Levine, MD Clinical Associate Professor of Medicine, UCLA 1. Josephson ME, An irregular narrow QRS tachycardia. What is your diagnosis? Arrhythmia Grand Rounds 2015; 1: 32-34; DOI: 10.12945/j.agr.2015.000020-14 2. Salehi H, Jhand AS, Satigan V, Lahawijan W, Thakur AK, A difficult journey: an irregular wide QRS tachycardia, Arrhythmia Grand Rounds 2015; 1: 38-41; DOI: 1012945/j.agr.2015.00021-14