What is the treatment for Supraventricular Tachycardia (SVT)?

Treatment of Supraventricular Tachycardia (SVT)

The treatment of SVT follows a stepwise approach, with vagal maneuvers as first-line intervention, adenosine as second-line, calcium channel blockers or beta blockers as third-line, and synchronized cardioversion for refractory or unstable cases. 1

First-Line Treatment: Vagal Maneuvers

• Modified Valsalva maneuver is the most effective vagal technique (43% effective) 1, 2
• Other options include carotid sinus massage and cold stimulus (ice to face)
• Switching between different vagal techniques can increase overall success rate to 27.7% 1
• These should be attempted before pharmacological interventions in hemodynamically stable patients (Class I, Level B-R) 1

Second-Line Treatment: Adenosine

• Adenosine IV is recommended when vagal maneuvers fail (91% effective) 1, 2
• Initial dose: 6 mg rapid IV bolus
• Up to 2 subsequent doses of 12 mg may be administered if ineffective
• For pediatric patients: 0.1 mg/kg, which can be increased to 0.2 mg/kg 1

Third-Line Treatment: Calcium Channel Blockers or Beta Blockers

• Verapamil IV is FDA-approved for rapid conversion of SVT to sinus rhythm 3

  • About 60% of patients convert to normal sinus rhythm within 10 minutes after IV verapamil 3
  • Caution: Verapamil is contraindicated in patients with:
    • Accessory bypass tracts (Wolff-Parkinson-White syndrome)
    • Ventricular tachycardia
    • Systolic heart failure 1, 3

• Beta blockers are recommended as third-line medications due to their excellent safety profile (Class IIa, Level B-R) 1

Fourth-Line Treatment: Synchronized Cardioversion

• Indicated for hemodynamically unstable patients or when medications fail
• Dose: 0.5-1 J/kg (Class I, Level B-NR) 1
• Should be performed in a setting with monitoring and resuscitation facilities 3

Long-Term Management

• Catheter ablation is recommended for recurrent, symptomatic SVT (Class I, Level B-NR)

  • Success rates of 93-98.5% with low complication rates (~3%) 1, 2
  • Considered first-line therapy to prevent recurrence 2

• Pharmacotherapy options for prevention include:

  • Beta blockers (first-line for infants, specifically propranolol) 1
  • Calcium channel blockers (contraindicated in infants) 1
  • Flecainide (for PSVT prevention in patients without structural heart disease) 1

Special Considerations

• Diagnostic pitfalls: Avoid mistaking ventricular tachycardia for SVT with aberrancy; when uncertain, treat as ventricular tachycardia 1
• Pregnancy: Same management algorithm applies, with careful electrode pad placement during cardioversion 1
• Contraindications:
  • Digoxin is potentially harmful in patients with pre-excited AF (Class III: Harm, Level C-LD) 1
  • Verapamil should be used with caution as a small fraction (<1%) of patients may develop life-threatening adverse responses 3

Monitoring and Follow-up

• All patients treated for SVT should be referred for heart rhythm specialist opinion 4
• Regular assessment with ECG and Holter monitoring is necessary 1
• Evaluation for accessory pathways is crucial 1

This stepwise approach ensures optimal management of SVT while minimizing risks and complications, with treatment decisions based on patient stability, response to initial interventions, and specific contraindications.