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 hemodynamically stable patients, and synchronized cardioversion for unstable patients or when pharmacological therapy fails. 1, 2

Acute Management

First-Line Treatments

• Vagal maneuvers should be performed first in hemodynamically stable patients with SVT 1, 2

  • Perform in supine position using proper technique:
    • Valsalva maneuver: bearing down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) 1, 2
    • Carotid sinus massage: apply steady pressure over carotid sinus for 5-10 seconds after confirming absence of bruits 1, 2
    • Cold stimulus: applying ice-cold wet towel to face 1
  • Success rate is approximately 27.7% when switching between techniques 2
  • NEVER apply pressure to eyeball (dangerous and abandoned practice) 1, 2

• Adenosine is recommended if vagal maneuvers fail 1, 2

  • Highly effective (91-95% success rate) for acute termination of SVT 1, 2, 3
  • Acts as both diagnostic and therapeutic agent 1
  • Monitor for brief side effects (occur in ~30% of patients) 1
  • Have resuscitation equipment available as adenosine may precipitate atrial fibrillation 1

Second-Line Treatments (for hemodynamically stable patients)

• Calcium channel blockers (IV diltiazem or verapamil) are effective for acute treatment 1, 2

  • Particularly effective for AVNRT conversion to sinus rhythm 1
  • Only use in hemodynamically stable patients 1

• Beta blockers (IV) are reasonable for acute treatment in stable patients 1, 2

  • Less effective than calcium channel blockers 2

Emergency Treatment

• Synchronized cardioversion is indicated for: 1, 2
  • Hemodynamically unstable patients when vagal maneuvers/adenosine fail or aren't feasible
  • Hemodynamically stable patients when pharmacological therapy fails or is contraindicated
  • Immediate treatment for hemodynamically unstable patients with pre-excited AF 1

Special Considerations

Pre-excited AF

• Avoid AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation 2
  • These may accelerate ventricular rate and lead to ventricular fibrillation 2
• Use ibutilide or IV procainamide for hemodynamically stable patients with pre-excited AF 1, 2

Long-Term Management

Pharmacological Options

• Oral medications for ongoing management: 1
  • First-line: Beta blockers, diltiazem, or verapamil for symptomatic SVT without pre-excitation 1
  • Second-line: Flecainide or propafenone for patients without structural heart disease 1, 4
    • Flecainide is indicated for prevention of PSVT and paroxysmal atrial fibrillation/flutter 4
    • Monitor for proarrhythmic effects (can cause new or worsened arrhythmias) 4
  • Third-line: Sotalol, dofetilide, amiodarone, or digoxin may be considered when other options fail 1

Definitive Treatment

• Electrophysiological study with catheter ablation is highly effective (94.3-98.5% success rate) 1, 3
  • Recommended as first-line therapy to prevent recurrence of SVT 3
  • Should be considered for patients with symptomatic, recurrent SVT 1

Important Pitfalls to Avoid

• Ensure proper ECG diagnosis before treatment to distinguish SVT from ventricular tachycardia 2
• Never use AV nodal blocking agents in patients with suspected pre-excitation, VT, or systolic heart failure 2
• Flecainide should not be used in patients with structural heart disease, recent myocardial infarction, or chronic atrial fibrillation 4
• Monitor for proarrhythmic effects with antiarrhythmic medications, especially in the first 14 days of therapy 4