Supraventricular Tachycardia in Infants

Common in infants. May be first presentation of WPW.

ECG

  • Beat varies widely (cf adults)
  • Up to 300 / min (infants only), 160 older children
  • QRS narrow
  • Always assume wide complex = VT

SVT vs Sinus Tachycardia

  • Sinus < 220 beats/minute
  • Variable rate in SVT
  • SVT responds to vagal / adenosine
  • P waves often visible in both!

Treatment

Cardioversion

  • Reserved for patients in shock or CHF
  • Initial dose= 0.5-1.0 watt sec/kilogram

Vagal

  • Diving reflex
  • Iced cloth over nose/mouth for 20 - 30 sec

Digoxin

  • Effective, safe, and long track record
  • Slow onset action

Adenosine

  • Drug of choice

  • Innitial dose= 0.1 mg/kg, may be doubled
  • If Adenosine Fails To Convert
    • 12 lead ECG to reevaluate rhythm (? sinus)
    • Consider cardioversion for SVT

Verapamil

  • Slows conduction, prolongs refractory period of AV node
  • Should be avoided in infants (hypotension)
  • Avoided if chance bypass tract (wide complex)