Adenosine should never be used in the setting of a wide complex regular tachycardia as a diagnostic maneuver. Adenosine will convert some types of VT, and this may mislead the health care provider into thinking that the WCT is an SVT. The electrophysiology literature is rife with reports of "adenosine-sensitive VT," and these patients are often young and without prior history of CAD...the very patients that we'd most be inclinded to assume have SVT.
The bottom line is that one should always assume that a regular WCT (without obvious evidence of sinus tachycardia) is VT, and treat the tachydysrhythmia as such.
