Evaluate for underlying causes (e.g. electrolyte imbalances, ACS)
Wide QRS (>100ms or 3 small boxes)
QRS complexes of varied amplitude, axis and duration
Torsades: QRS complexes appear to twist around isoelectric line
Rapid rhythm (usually 140-160 bpm, but can be up to 300 bpm)
Irregular
Torsades: QRS complexes appear to twist around isoelectric line
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: