He presented to urgent care and was found to be in wide complex tachycardia at the rate of about 200 bpm (Figure 1). The patient was given diltiazem intravenously and converted to atrial flutter ...

The three irregularly irregular rhythms are atrial fibrillation ... and ventricular tachycardia. Treat a wide-complex tachycardia like ventricular tachycardia until proven otherwise.

At times it can be difficult to distinguish "SVT with aberrancy" from ventricular tachycardia ... wide R wave in lead V1 or V2 measuring > 40 ms (one little box). This is not the case in the QRS ...