What is the treatment for Supraventricular Tachycardia (SVT)?

Treatment of Supraventricular Tachycardia (SVT)

The treatment of SVT should follow a stepwise approach starting with vagal maneuvers, followed by adenosine for acute termination, and consideration of catheter ablation as definitive therapy for recurrent episodes. 1, 2

Acute Management

First-line Interventions

• Vagal maneuvers should be performed as the initial treatment for hemodynamically stable patients with SVT 1, 2
  • Perform in supine position using proper technique 2
  • Valsalva maneuver: patient bears down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) 1
  • Carotid sinus massage: apply steady pressure over carotid sinus for 5-10 seconds (after confirming absence of carotid bruit) 1, 2
  • Modified Valsalva has higher success rate (43.7%) compared to standard Valsalva (24.2%) and carotid sinus massage (9.1%) 3

Second-line Interventions

• Adenosine (Class I recommendation) should be administered if vagal maneuvers fail 1, 2
  • Highly effective (91-95% success rate) for acute termination of SVT 2, 4
  • Brief side effects occur in approximately 30% of patients (chest discomfort, dyspnea, flushing) 1
  • Caution: may precipitate atrial fibrillation that could conduct rapidly to ventricles 1

Third-line Interventions

• Intravenous calcium channel blockers (diltiazem or verapamil) are reasonable for hemodynamically stable patients (Class IIa recommendation) 1, 2
• Intravenous beta-blockers can be considered for hemodynamically stable patients (Class IIa recommendation) 1, 2

For Hemodynamically Unstable Patients

• Synchronized cardioversion is recommended when patients are hemodynamically unstable or when pharmacological therapy fails (Class I recommendation) 1

Long-term Management

Pharmacological Options

• Oral medications for ongoing management in symptomatic patients:
  • First-line: Beta-blockers, diltiazem, or verapamil (Class I recommendation) 1
  • Second-line: Flecainide or propafenone in patients without structural heart disease (Class IIa recommendation) 1, 5
    • Caution: Flecainide can cause proarrhythmic effects, especially in patients with structural heart disease 5
  • Third-line: Sotalol (Class IIb recommendation) 1
  • Fourth-line: Dofetilide or amiodarone (Class IIb recommendation) 1

Definitive Treatment

• Electrophysiological study with catheter ablation is highly effective and recommended as first-line therapy for prevention of recurrent SVT 1, 4
  • Success rates of 94.3-98.5% with a single procedure 4
  • Particularly recommended for AVNRT due to low risk of complications 6

Special Considerations

• Pre-excited AF (with accessory pathway):

  • Avoid AV nodal blocking agents (verapamil, diltiazem, beta-blockers) as they may accelerate ventricular rate 2
  • Use synchronized cardioversion for hemodynamically unstable patients 1
  • Use ibutilide or IV procainamide for hemodynamically stable patients 1

• Proper diagnosis is essential before treatment to distinguish SVT from ventricular tachycardia 2

• Patient education on how to perform vagal maneuvers is important for ongoing management 1

Common Pitfalls to Avoid

• Never apply pressure to the eyeball as this practice is dangerous 1, 2
• Always confirm absence of carotid bruits before performing carotid sinus massage 1, 2
• Avoid calcium channel blockers and beta-blockers in patients with suspected pre-excited AF, as they may accelerate ventricular rate 2
• Do not use flecainide in patients with structural heart disease or recent myocardial infarction due to increased risk of proarrhythmic effects 5