This is an interesting case I wanted to share with you. This was an older person with a wide complex tachycardia. The most important thing from this case I want everyone to know is that you will never go wrong by treating these patients as if the rhythm were ventricular tachycardia.
The differential for wide complex regular tachycardia includes: V-tach, SVT with bundle branch, and sinus tachycardia with bundle branch or with WPW. The thing you must remember is that there is no reliable way of ruling out VT with these patients on a 12-lead ECG. My medication treatment of choice is procainamide. Lidocaine and amiodarone are still acceptable therapies, but case reports of adverse outcomes if this is, in fact, a very fast irregular tachycardia have been reported (see below.)
The differential for wide complex irregular tachycardia includes: Afib with bundle branch block and afib with pre-excitation (e.g. WPW.) At very rapid rates these can appear regular. Again, you can not go wrong by treating as VT. The only effective treatments are procainamide or cardioversion.
The two medication class you should avoid are calcium channel blockers and beta blockers.