Narrow Complex Tachycardia

Pathology:                  

Abnormalheart rhythm arising from improper electrical activity in the atria

These are divided into 2 groups

Atrioventricularnodal re-entrant tachycardia (AVNRT)

Atrioventricular re-entrant tachycardia (AVRT)

Aetiology:                  

‍AVNRT:Extra pathway within or close to the AV node, usually presents in late

teens, can beprecipitated by stress, emotion, exertion, caffeine, alcohol,  

hyperthyroidismand electrolyte abnormalities

AVRT: Accessory pathway between atria and ventricles(Wolff-Parkinson-White)

Symptoms:                  

Regularpalpitations sometimes radiating into neck and ears, dizziness, syncope

Signs:                              

Rapidregular pulse, hypotension in some cases

Investigations:          

‍ECG:narrow complex tachycardia at approximately 200beats per minute

Echo: Toassess for structural abnormality

Treatment:                

Vagal manoeuvres e.g. Valsalva,carotid sinus massage, ice cold drink

IV adenosine (transiently blocks theAV node)

DCCV

Accessory pathway ablation

Complications:          

Sudden death in Wolff-Parkinson WhiteSyndrome occurs in approximately 0.4%

of patients however if patients are symptomatic therisk is increased therefore ablation of the accessory pathway is the treatmentof choice

Prognosis:                    

Excellent when treated

Figure 1.5 Narrow Complex Tachycardia - AVNRT