Wide complex tachycardia in the context of >>>>>
Digitalis toxicity = Epanutin or lidocaine .
Prolonged QT and TdP = mg sulphate and correction of hypokalemia (Amiodarone is contraindicated).
TCA toxicity = NaHco3 and correction of electrolyte disturbance ( amiodarone is contraindicated )
Heart failure or IHD = Amiodarone ( or DC shock if unstable).
WPW and normal heart = IV flecanide or Propafenone ( or amiodarone with structural abnormality ) .
Preexcited AF ( irregular WCT , very fast 
)= DC shock ( even if blood pressure is normal ) .
Idiopathic RVOT VT ( young patient , LBBB morphology , normal Echo , stable )= IV adenosine .