Abbreviation:<unk> 
Congenital pre-excitation syndrome
Presence of an accessory electrical pathway between atria and ventricles predisposing to supraventricular tachycardia
Associated with certain genetic predispositions, Ebstein anomaly, and hypokalemic periodic paralysis 
Type A
Pathway between the left atrium and ventricle
Delta wave and QRS complex predominantly upright in precordial leads 
Dominant R wave (greater than S amplitude) in V1 may have appearance of right bundle branch block 
Type B
Pathway between the right atrium and ventricle
Delta wave and QRS complex predominantly negative in V1 and V2
Delta wave and QRS complex predominantly positive in other precordial leads 
Appearance of left bundle branch block 
Pathway between the left atrium and ventricle
Delta wave and QRS complex predominantly upright in precordial leads 
Dominant R wave (greater than S amplitude) in V1 may have appearance of right bundle branch block 
Pathway between the right atrium and ventricle
Delta wave and QRS complex predominantly negative in V1 and V2
Delta wave and QRS complex predominantly positive in other precordial leads 
Appearance of left bundle branch block 
Orthodromic
Accessory pathway with retrograde reentry conduction
Most common variant (~95% of cases)
QRS narrow (delta wave absent)
Referred to as 'concealed' accessory pathway 
May see ST depression, TWI
Rate 150-250 bpm
Antidromic
Accessory pathway with anterograde reentry conduction
Least common variant (~5% of cases)
QRS wide, delta wave present
Rate 160-220 bpm, regular
Accessory pathway with retrograde reentry conduction
Most common variant (~95% of cases)
QRS narrow (delta wave absent)
Referred to as 'concealed' accessory pathway 
May see ST depression, TWI
Rate 150-250 bpm
Referred to as 'concealed' accessory pathway 
Accessory pathway with anterograde reentry conduction
Least common variant (~5% of cases)
QRS wide, delta wave present
Rate 160-220 bpm, regular
Atrial fibrillation in up to 20% of patients with<unk> 
Irregular rhythm, wide QRS complexes
Changing QRS complexes in shape and morphology
Axis remains stable as opposed to polymorphic VT
Atrial flutter in ~7% of patients with<unk> 
Similar features to atrial fibrillation with<unk> 
Except regular rhythm
Easily mistaken for monomorphic ventricular tachycardia
Note that if unclear, always safest to assume VT and treat with shock
Treatment with AV nodal blocking agents (adenosine, beta-blockers, calcium-channel blockers, amiodarone, digoxin) may incite ventricular fibrillation or ventricular tachycardia
"Manifest<unk> " = degeneration into VT or VF
Irregular rhythm, wide QRS complexes
Changing QRS complexes in shape and morphology
Axis remains stable as opposed to polymorphic VT
Similar features to atrial fibrillation with<unk> 
Except regular rhythm
Easily mistaken for monomorphic ventricular tachycardia
Note that if unclear, always safest to assume VT and treat with shock
Wolff–Parkinson–White syndrome
Regular
Wernicke-Korsakoff syndrome
AV Node Independent
Vaughn Jackson syndrome
Sinus tachycardia
Sydenham's chorea
Atrial tachycardia 