Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular tachycardia with abberancy)
Regular
Monomorphic ventricular tachycardia
PSVT with aberrant conduction:
PSVT with bundle branch block^
PSVT with accessory pathway
Atrial flutter with bundle branch block^
Sinus tachycardia with bundle branch block^
Accelerated idioventricular rhythm (consider if less than or ~120 bpm)
Metabolic
Hyperkalemia
Digoxin toxicity
Severe metabolic acidosis
Irregular
Atrial fibrillation/atrial flutter with variable AV conduction AND bundle branch block^
Atrial fibrillation/atrial flutter with variable AV conduction AND accessory pathway (e.g. WPW)
Atrial fibrillation + hyperkalemia
Polymorphic ventricular tachycardia
Torsades de pointes
Nonsustained ventricular tachycardia
Monomorphic ventricular tachycardia
PSVT with aberrant conduction:
PSVT with bundle branch block^
PSVT with accessory pathway
Atrial flutter with bundle branch block^
Sinus tachycardia with bundle branch block^
Accelerated idioventricular rhythm (consider if less than or ~120 bpm)
Metabolic
Hyperkalemia
Digoxin toxicity
Severe metabolic acidosis
PSVT with bundle branch block^
PSVT with accessory pathway
Atrial flutter with bundle branch block^
Hyperkalemia
Digoxin toxicity
Severe metabolic acidosis
Atrial fibrillation/atrial flutter with variable AV conduction AND bundle branch block^
Atrial fibrillation/atrial flutter with variable AV conduction AND accessory pathway (e.g. WPW)
Atrial fibrillation + hyperkalemia
Polymorphic ventricular tachycardia
Torsades de pointes
Nonsustained ventricular tachycardia
Torsades de pointes
Nonsustained ventricular tachycardia
^Fixed or rate-related
A fib/SVT
Oversensing
Lead fracture
Electrical storm
Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise 
Heat stroke
Regular
Undifferentiated shock
Monomorphic ventricular tachycardia
Undifferentiated shock 
PSVT with aberrant conduction: