What are the treatment options for supraventricular tachycardia (SVT)?

Treatment Options for Supraventricular Tachycardia (SVT)

The most effective treatment approach for SVT begins with vagal maneuvers, followed by adenosine for hemodynamically stable patients, and immediate synchronized cardioversion for unstable patients. 1, 2

Acute Management Algorithm

Step 1: Assess Hemodynamic Stability

• Determine if the patient is hemodynamically stable or unstable (look for hypotension, altered mental status, signs of shock, chest pain, or acute heart failure) 2
• For hemodynamically unstable patients, proceed directly to synchronized cardioversion 1, 2

Step 2: Vagal Maneuvers (for stable patients)

• Modified Valsalva maneuver is the most effective vagal technique with success rates up to 43% 3
• Perform vagal maneuvers in a supine position for optimal effectiveness 1
• Other techniques include standard Valsalva maneuver and carotid sinus massage (only after confirming absence of carotid bruits) 1, 4

Step 3: Pharmacological Management (if vagal maneuvers fail)

• Adenosine is the first-line drug for hemodynamically stable patients with 90-95% effectiveness 1, 2
• If adenosine fails, consider:
  • Calcium channel blockers (diltiazem or verapamil) - highly effective with 80-98% conversion rates 1, 2
  • Beta-blockers - less effective than calcium channel blockers but still a viable option 1

Special Considerations

Pre-excited Atrial Fibrillation

• For hemodynamically unstable patients with pre-excited AF, use synchronized cardioversion 1, 2
• For stable patients with pre-excited AF, use ibutilide or IV procainamide 1, 2
• AVOID AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation as they may accelerate ventricular rate and lead to ventricular fibrillation 1, 2

Long-term Management

• Catheter ablation is the most effective therapy to prevent recurrent SVT, with success rates of 94.3-98.5% 2, 3
• For patients who decline ablation or are not candidates, pharmacological options include:
  • Oral beta blockers, diltiazem, or verapamil 2
  • Flecainide for patients without structural heart disease 2, 5

Important Caveats and Pitfalls

• Proper ECG diagnosis is essential before treatment to distinguish SVT from ventricular tachycardia 1
• NEVER apply pressure to the eyeball as a vagal maneuver - this practice is dangerous 1
• Flecainide can cause proarrhythmic effects, especially in patients with structural heart disease or recent myocardial infarction 5
• In patients with paroxysmal atrial fibrillation treated with flecainide, 4% experienced proarrhythmic events 5
• Calcium channel blockers and beta-blockers should be avoided in patients with suspected pre-excited AF, ventricular tachycardia, or systolic heart failure 1, 2
• Carotid sinus massage should only be performed after confirming the absence of carotid bruits 1