Wide complex tachycardia and hypotension in a 50-something with h/o cardiomyopathy -- what is it?

A 50-something male with unspecified history of cardiomyopathy presented in diabetic ketoacidosis (without significant hyperkalemia) with a wide complex tachycardia and hypotension.Bedside echo showed " mildly reduced " LV EF.Here is the ED ECG:What do you think?Analysis: there is a wide complex tachycardia. It is regular.  There are no P-waves.  The morphology is of RBBB and LAFB.  The initial part of the QRS is very fast, suggesting that it starts in conducting fibers and not in myocardium.  Thus, it is probably SVT with aberrancy (RBBB + LAFB) or it is posterior fascicular VT (which starts in the posterior fascicle and therefore also has a fast initial depolarization nearly identical to RBBB + LAFB).The fact that he has a cardiomyopathy argues for a more typical ventricular tachycardia, as does the absence of rSR ' in lead V1.  One of the Brugada criteria is RBBB pattern but with the firsr R-wave being larger than the 2nd (true RBBB has rSR ' -- that is, the first r- is small and the 2nd R- is large).The providers for this patient did not spend a lot of time trying to figure this out.  Because the patient was critically ill, they just went ahead and sedated and cardioverted.  They probably would have had time to give adenosine (after all, they had time to draw up sedatives prior to electrical cardioversion).  Adenosine is safe even if it is VT.  If it is posterior fascicular VT, then verapamil works, but that is very risky ...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs