Form of<unk>  tachycardia
Multiple<unk>  foci
QRS complexes with varying morphology
Subtypes include:
Torsades de pointes
bidirectional<unk>  VTach (as seen in digoxin toxicity)
Multiple<unk>  foci
QRS complexes with varying morphology
Torsades de pointes
bidirectional<unk>  VTach (as seen in digoxin toxicity)
Myocardial ischemia (most common)
Acquired or congenital prolonged QT
TCAs, phenothiazines, Type I antiarrhythmics (quinidine, procainamide)
Hypokalemia
Hypomagnesemia
Elevated intracranial pressure
Brugada syndrome, short QT syndrome, congenital catecholaminergic<unk> 
TCAs, phenothiazines, Type I antiarrhythmics (quinidine, procainamide)
Hypokalemia
Hypomagnesemia
Elevated intracranial pressure
Polymorphic ventricular tachycardia
Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise 
Wandering atrial pacemaker
Regular
Wide-complex tachycardia
Monomorphic ventricular tachycardia
Accelerated idioventricular rhythm
PSVT with aberrant conduction: