Supraventricular Tachycardia (SVT)

Supraventricular Tachycardia (SVT)

David Ray Velez, MD

A Rapid Rhythm that Originates from Foci at or Above the Atrioventricular (AV) Node

  • The Term “SVT” is Often Mistakenly Used Synonymously with Atrioventricular Nodal Reentrant Tachycardia (AVNRT) – A Type of SVT
  • Sinus Tachycardia and Atrial Fibrillation are Technically Types of SVT

Types

  • Atrial Origin, Regular Rhythm:
    • Sinus Tachycardia
    • Atrial Flutter
    • Focal Atrial Tachycardia
    • Sinoatrial Nodal Reentry Tachycardia (SNART)
  • Atrial Origin, Irregular Rhythm:
    • Atrial Fibrillation
    • Multifocal Atrial Tachycardia (MAT)
  • AV Nodal Origin, Regular Rhythm:
    • Atrioventricular Nodal Reentrant Tachycardia (AVNRT)
    • Atrioventricular Reentrant Tachycardia (AVRT)
    • Junctional Ectopic Tachycardia

General EKG Pattern

  • Heart Rate > 100 bpm
  • Narrow QRS Complex (< 120 ms)
  • Compared to Sinus Tachycardia:
    • Often Has No Identified Underlying Cause
    • Sudden Onset
    • Rate is Usually Very High > 150 bpm
    • Typically See Combined P and T Waves
    • Generally Symptomatic (Chest Pain, Dyspnea, Anxiety)
    • Often Has Limited Rate Variability

Supraventricular Tachycardia (SVT)

Treatment

  • Unstable: Synchronized Cardioversion
  • Stable: Vagal Maneuvers and Adenosine
    • Try Vagal Maneuvers Initially and then Give Adenosine if Fails
      • Ex: Carotid Massage or Valsalva Maneuver
      • 12-18% Success
    • Adenosine Dosing: 6 mg IV Rapidly Over 1-3 Seconds
      • Can Repeat with 12 mg Doses if Needed
      • Decrease Dose by 50% if Given Through a Central Line (3 mg/6 mg)
    • *See Antiarrhythmic Pharmacology