A 50-something with Regular Wide Complex Tachycardia: What to do if electrical cardioversion does not work?

Case submitted by anonymous. Written by Smith.  Ken ' s piece at the bottom is excellent.A 50-something presented with sudden onset palpitations 8 hrs prior while sitting at desk at work. He had concurrent sharp substernal chest pain that resolved, but palpitations continued.Over past 3 months, he has had similar intermittent episodes of sharp chest pain while running, but none at rest. Past medical history includes coronary stenting 17 years prior. A brief chart review revealed his most recent echo in 2018, with LV EF 67%, “very small” inferior wall motion abnormality.Initial ED ECG:What do you think?This was shown to me with no clinical information and I said " It is VT until proven otherwise. "  Why did I say that?1.It does not look like RBBB or LBBB; therefore, if there is aberrancy, it is atypical aberrancy2. The rapidity of onset of the QRS is slow (in SVT with aberrancy, the first part of the QRS is through fast conducting Purkinje fibers and is therefore narrow).  Look at the R-wave in V4: it takes 60 ms to reach its peak.  It should be less than 30 ms.3. It has a" Northwest Axis " (towards aVR).  Correspondingly, as Ken notes below, the inferior leads are 100% negative, which virtually never happens in SVT.4. There is a 40 ms q wave in aVR.  5. The 2 R-waves in V1 fulfillBrugada criterion of having the first R larger than the 2nd R (in true RBBB, the first r-wave is small and the 2nd R ' -wave is large)6. The...
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