Tachyarrhythmias

Approach to Narrow Complex Tachycardia

Sinus Tachycardia

Regular narrow complex tachycardia with uniform P waves and PR intervals

Focal Atrial Tachycardia

Regular narrow complex tachycardia with abnormal yet consistent P waves

Multifocal Atrial Tachycardia

Irregular narrow complex tachycardia with multiple P wave morphologies and variable PP intervals

Atrial Flutter

Regular narrow complex tachycardia with sawtooth waves

Atrial Fibrillation

Irregular narrow complex tachycardia with absence of P waves and disorganised atrial activity

AV Nodal Reentrant Tachycardia

Regular narrow complex tachycardia with P waves hidden within QRS

AV Reentrant Tachycardia

Orthodromic or antidromic

Regular narrow complex tachycardia with P waves visible after QRS (orthodromic)

Causes of wide complex tachycardia

Distinguishing VT and SVT with aberrancy

Monomorphic Ventricular Tachycardia

Regular tachycardia with broad QRS

Polymorphic Ventricular Tachycardia

Multiple ventricular ectopic morphologies

SVT with Aberrancy or Preexcitation

Regular tachycardia with broad QRS complexes

AF with Aberrancy or Preexcitation

Irregular tachycardia with broad QRS complexes

Ventricular Fibrillation

Chaotic electrical activity without PQRST