What is the treatment for supraventricular tachycardia (SVT)?

Treatment for Supraventricular Tachycardia (SVT)

The first-line treatment for hemodynamically stable SVT is vagal maneuvers, specifically the modified Valsalva maneuver, followed by adenosine if unsuccessful, while synchronized cardioversion is the first-line treatment for hemodynamically unstable patients. 1

Acute Management Algorithm

Hemodynamically Stable Patients

1. First-line: Vagal Maneuvers (Class I, Level B-R) 1

   • Modified Valsalva maneuver is most effective 1, 2
   • Other options include carotid sinus massage or applying ice to the face
   • Modified Valsalva has superior conversion rates (43.7%) compared to standard Valsalva (24.2%) or carotid sinus massage (9.1%) 3

2. Second-line: Adenosine IV (Class I, Level B-R) 1

   • Initial dose: 6 mg rapid IV bolus
   • If ineffective, up to 2 subsequent doses of 12 mg may be administered
   • For pediatric patients: 0.1 mg/kg, may increase to 0.2 mg/kg 1

3. Third-line: IV Calcium Channel Blockers or Beta Blockers (Class IIa, Level B-R) 1

   • Calcium channel blockers (diltiazem, verapamil)
     • Contraindicated in heart failure
     • Avoid in suspected ventricular tachycardia, pre-excited atrial fibrillation, or systolic heart failure
   • Beta blockers
     • Excellent safety profile

4. Fourth-line: Synchronized Cardioversion (Class I, Level B-NR) 1

Hemodynamically Unstable Patients

• Immediate Synchronized Cardioversion (Class I, Level B-NR) 1
  • Dose: 0.5-1 J/kg

Long-term Prevention of Recurrent SVT

1. First-line Medications:

   • Beta blockers (Class IIa, Level B-R) 1
     • Recommended for their excellent safety profile
     • Propranolol is first-line for infants 1
   • Calcium channel blockers (Class IIa, Level B-R) 1
     • Contraindicated in infants due to risk of hypotension and cardiovascular collapse

2. Alternative Medications:

   • Flecainide (Class IIa, Level B) 1, 4
     • Indicated for prevention of PSVT in patients without structural heart disease
     • Contraindicated in patients with recent myocardial infarction or structural heart disease 1, 4
     • Requires careful monitoring due to proarrhythmic effects 4

3. Definitive Treatment:

   • Catheter ablation (Class I, Level B-NR) 1
     • Recommended for recurrent, symptomatic SVT
     • Success rates of 93-95% with low complication rates (approximately 3%)

Important Considerations and Pitfalls

• Diagnostic Errors: Avoid mistaking ventricular tachycardia for SVT with aberrancy; when uncertain, treat as ventricular tachycardia 1

• Treatment Approach Errors: Do not delay cardioversion in unstable patients 1

• Special Populations:

  • Pregnant patients: Same management algorithm applies (vagal maneuvers → adenosine → cardioversion) with careful electrode pad placement 1
  • Infants: Beta blockers (propranolol) are first-line; avoid verapamil 1

• Contraindications:

  • Digoxin is potentially harmful in patients with pre-excited AF (Class III: Harm, Level C-LD) 1
  • Diltiazem and verapamil should be avoided in suspected ventricular tachycardia, pre-excited atrial fibrillation, or systolic heart failure 1

• Monitoring: Regular assessment with ECG and Holter monitoring is necessary for all SVT patients 1

• Evaluation: Assess for accessory pathways, especially Wolff-Parkinson-White syndrome 1