Regular
AV Node Independent
Sinus<unk> 
Atrial<unk>  (uni-focal or multi-focal)
Atrial fibrillation
Atrial flutter
Idiopathic fascicular left ventricular<unk> 
AV Node Dependent
Paroxysmal supraventricular<unk>  (PSVT)
AV node re-entry<unk>  (AVNRT)
AV re-entry<unk>  (AVRT)
Lown-Ganong-Levine syndrome
Wolff–Parkinson–White syndrome
Junctional<unk> 
Irregular
Multifocal atrial<unk>  (MAT)
Sinus<unk>  with frequent PACs, PJCs, PVCs
Atrial fibrillation
Atrial fibrillation with RVR
Atrial flutter with variable conduction
Digoxin Toxicity
AV Node Independent
Sinus<unk> 
Atrial<unk>  (uni-focal or multi-focal)
Atrial fibrillation
Atrial flutter
Idiopathic fascicular left ventricular<unk> 
AV Node Dependent
Paroxysmal supraventricular<unk>  (PSVT)
AV node re-entry<unk>  (AVNRT)
AV re-entry<unk>  (AVRT)
Lown-Ganong-Levine syndrome
Wolff–Parkinson–White syndrome
Junctional<unk> 
Sinus<unk> 
Atrial<unk>  (uni-focal or multi-focal)
Atrial fibrillation
Atrial flutter
Idiopathic fascicular left ventricular<unk> 
Paroxysmal supraventricular<unk>  (PSVT)
AV node re-entry<unk>  (AVNRT)
AV re-entry<unk>  (AVRT)
Lown-Ganong-Levine syndrome
Wolff–Parkinson–White syndrome
Junctional<unk> 
AV node re-entry<unk>  (AVNRT)
AV re-entry<unk>  (AVRT)
Lown-Ganong-Levine syndrome
Wolff–Parkinson–White syndrome
Lown-Ganong-Levine syndrome
Wolff–Parkinson–White syndrome
Multifocal atrial<unk>  (MAT)
Sinus<unk>  with frequent PACs, PJCs, PVCs
Atrial fibrillation
Atrial fibrillation with RVR
Atrial flutter with variable conduction
Digoxin Toxicity
Atrial fibrillation with RVR
Assume any wide-complex<unk>  is ventricular<unk>  until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular<unk>  with abberancy)
Regular
Monomorphic ventricular<unk> 
PSVT with aberrant conduction:
PSVT with bundle branch block^
PSVT with accessory pathway
Atrial flutter with bundle branch block^
Sinus<unk>  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<unk> 
Torsades de pointes
Nonsustained ventricular<unk> 
Monomorphic ventricular<unk> 
PSVT with aberrant conduction:
PSVT with bundle branch block^
PSVT with accessory pathway
Atrial flutter with bundle branch block^
Sinus<unk>  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<unk> 
Torsades de pointes
Nonsustained ventricular<unk> 
Torsades de pointes
Nonsustained ventricular<unk> 
^Fixed or rate-related
Narrow-complex tachycardia
Regular
Wide-complex tachycardia
AV Node Independent
Junctional tachycardia
Sinus tachycardia
Wandering atrial pacemaker
Atrial tachycardia 