What are the oral treatment options for Supraventricular Tachycardia (SVT)?

Oral Treatment Options for Supraventricular Tachycardia (SVT)

For ongoing management of symptomatic SVT, oral beta blockers, diltiazem, or verapamil are the first-line pharmacological options, with catheter ablation being the definitive treatment for recurrent cases. 1

First-Line Oral Medications

• Beta blockers (Class I recommendation, Level B-R evidence):

  • Atenolol: 25-50 mg once daily, maximum 100 mg daily 1
  • Metoprolol tartrate: 25 mg twice daily, maximum 200 mg twice daily 1
  • Metoprolol succinate: 50 mg once daily (long-acting), maximum 400 mg daily 1
  • Nadolol: 40 mg once daily, maximum 320 mg daily 1
  • Propranolol: 30-60 mg in divided doses, maximum 160 mg daily 1
  • Caution: Avoid in patients with AV block greater than first degree, sinus node dysfunction, decompensated heart failure, hypotension, or reactive airway disease 1

• Calcium channel blockers (Class I recommendation, Level B-R evidence):

  • Diltiazem: 120-360 mg daily in divided doses 1
  • Verapamil: 120-480 mg daily in divided doses 1
  • Caution: Avoid in patients with heart failure, hypotension, or pre-excitation syndromes 1

Second-Line Oral Medications

• Flecainide (Class IIa recommendation, Level B-R evidence):

  • Initial dose: 50 mg every 12 hours 2
  • May increase in increments of 50 mg twice daily every four days 2
  • Maximum dose: 300 mg daily 2
  • Only for patients without structural heart disease or ischemic heart disease 1, 2
  • Requires in-hospital initiation with rhythm monitoring for sustained VT 2

• Propafenone (Class IIa recommendation, Level B-R evidence):

  • 150 mg three times daily 1
  • Only for patients without structural heart disease or ischemic heart disease 1

Third-Line Oral Medications

• Sotalol (Class IIb recommendation, Level B-R evidence):

  • May be reasonable for patients who are not candidates for catheter ablation 1
  • Requires careful monitoring for QT prolongation 1

• Dofetilide (Class IIb recommendation, Level B-R evidence):

  • 500 μg twice daily has shown 50% probability of complete symptom suppression over 6 months 1
  • Consider when beta blockers, diltiazem, flecainide, propafenone, or verapamil are ineffective or contraindicated 1

• Amiodarone (Class IIb recommendation, Level C-LD evidence):

  • Maintenance dose: 200-400 mg daily 1
  • Reserved for patients when other medications are ineffective or contraindicated 1
  • Has been shown to be safe in patients with structural heart disease and LV dysfunction 1

• Digoxin (Class IIb recommendation, Level C-LD evidence):

  • May be reasonable in patients without pre-excitation 1
  • Less commonly used due to availability of more effective options 1

"Pill-in-the-Pocket" Approach

• Single-dose oral therapy (Class IIb recommendation, Level C-LD evidence):
  • Diltiazem (120 mg) plus propranolol (80 mg) taken together at onset of SVT 1
  • Appropriate for patients with infrequent but prolonged episodes 1
  • Patients should be free of significant LV dysfunction, sinus bradycardia, or pre-excitation 1
  • Has been shown to reduce emergency room visits 1
  • Caution: Risk of syncope has been observed 1

Special Populations

Pregnancy

• Preferred medications (Class IIa recommendation, Level C-LD evidence) 1:
  • Metoprolol
  • Propranolol
  • Digoxin
  • Flecainide
  • Propafenone
  • Sotalol
  • Verapamil

Pediatric Patients

• Beta blockers and calcium channel blockers show similar efficacy (approximately 65-69% success rate after dose adjustments) 3
• Beta blockers are associated with more side effects (18%) compared to calcium channel blockers 3

Definitive Treatment

• Catheter ablation (Class I recommendation, Level B-NR evidence):
  • Success rates of 94-98.5% 4
  • First-line therapy for recurrent SVT 1
  • Provides definitive cure without need for chronic medication 1
  • Low complication rates (1% risk of AV block for AVNRT) 1

Clinical Pearls and Pitfalls

• Always rule out pre-excitation (Wolff-Parkinson-White syndrome) before starting calcium channel blockers, as they can accelerate conduction through accessory pathways and potentially cause ventricular fibrillation 1
• Flecainide should never be used in patients with structural heart disease due to proarrhythmic risk 1, 2
• Medication effectiveness should be assessed after at least 3-5 days of therapy due to the long half-life of some agents (particularly flecainide) 2
• Patients should be educated on performing vagal maneuvers as a first-line approach to terminate acute episodes 1
• For patients with infrequent episodes, the "pill-in-the-pocket" approach may be preferable to daily medication 1