Supraventricular Tachycardia

EM Notes

Initial Steps to SVT

  1. Get the patient on a cardiac monitor, IV access,  crash cart, airway setup, and labs. 
  2. Stable or Unstable
  3. Is the rhythm regular or irregular? 
    • Irregular – AF, multifocal AT
    • Regular – sinus tachycardia, AV nodal reentrant tachycardia, AV reciprocating tachycardia, atrial flutter (usually), atrial tachycardia (AT)
Note: If tachycardia continues despite successful induction of at least some degree of AV nodal blockade, the rhythm is almost certainly AT or atrial flutter; AVRT is excluded, and AVNRT is very unlikely.
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SVT Management

Stable
Unstable

Adenosine 
6-mg rapid IV bolus.
If no result within 1–2 min, 12-mg rapid IV bolus; can repeat 12-mg dose 1 time.

Esmolol
250-500-mcg/kg IV bolus over 1 min.
Then infusion at 50–300 mcg/kg/min, with repeat boluses between each dosing increase

Amiodarone
150 mg IV over 10 min.
Then infusion at 1 mg/min (360 mg) over next 6 h; then 0.5 mg/min (540 mg) over remaining 18 h

Unstable patients with SVT and a pulse are always treated with synchronized cardioversion.

Narrow complex and Regular: 50-100J.
If sinus rhythm is not restored following an initial 50 to 100 joule shock, subsequent shocks should be at higher energy levels

Narrow complex and Irregular: 120-200J.

ECG following Adenosine

Further Learning