What is the treatment for Paroxysmal Supraventricular Tachycardia (PSVT)?

Treatment for Paroxysmal Supraventricular Tachycardia (PSVT)

Vagal maneuvers and adenosine are the preferred initial therapeutic choices for the termination of stable PSVT, followed by calcium channel blockers or beta-blockers if initial treatments fail, with synchronized cardioversion reserved for hemodynamically unstable patients or refractory cases. 1, 2

Initial Management of Stable PSVT

Step 1: Vagal Maneuvers

• First-line approach with approximately 27.7% success rate 2
• Options include:
  • Modified Valsalva maneuver (most effective vagal technique)
  • Carotid sinus massage (use caution in elderly or those with carotid disease)
  • Cold stimulus to face
• Vagal maneuvers alone will terminate up to 25% of PSVTs 1

Step 2: Adenosine

• If vagal maneuvers fail, administer adenosine:
  • Initial dose: 6 mg IV rapid push through a large vein followed by 20 mL saline flush
  • If no conversion within 1-2 minutes: 12 mg IV rapid push
  • Success rate: 91-95% 2
• Important considerations:
  • Have defibrillator available when administering (risk of atrial fibrillation with rapid ventricular rates in WPW)
  • Reduce initial dose to 3 mg in patients taking dipyridamole or carbamazepine, those with transplanted hearts, or if given by central venous access
  • Larger doses may be required with theophylline, caffeine, or theobromine
  • Contraindicated in asthma
  • Common side effects: flushing, dyspnea, chest discomfort (transient) 1

Step 3: Calcium Channel Blockers or Beta-Blockers

If adenosine fails or PSVT recurs:

• Non-dihydropyridine calcium channel blockers:
  • Verapamil: 2.5-5 mg IV bolus over 2 minutes; may repeat 5-10 mg every 15-30 minutes to total dose of 20 mg
  • Diltiazem: 15-20 mg (0.25 mg/kg) IV over 2 minutes; if needed, additional 20-25 mg (0.35 mg/kg) after 15 minutes; maintenance 5-15 mg/hour
• Beta-blockers (metoprolol, atenolol, propranolol, esmolol)
• Avoid verapamil in patients with impaired ventricular function or heart failure 1

Step 4: Synchronized Cardioversion

• Indicated for hemodynamically unstable patients or when pharmacological therapy fails
• Initial biphasic energy: 50-100 J for SVT
• If unsuccessful, increase energy in stepwise fashion 1, 2

Management of Hemodynamically Unstable PSVT

• Immediate synchronized cardioversion is the treatment of choice
• Highly effective in terminating SVT 2, 3

Long-Term Management

• Oral medications:
  • First-line: Beta-blockers, diltiazem, or verapamil 2
  • Second-line: Flecainide or propafenone (in patients without structural heart disease) 2, 4, 5
• Catheter ablation:
  • Definitive treatment with 94-98% success rate 2, 6
  • Recommended as first-line therapy to prevent recurrence 6
  • Provides potential cure without need for chronic medications

Special Considerations

• Flecainide and propafenone are contraindicated in patients with structural heart disease, recent myocardial infarction, or ventricular dysfunction 2, 4
• In pregnancy, adenosine is safe due to its short half-life 2
• For infrequent, well-tolerated episodes, a "pill-in-the-pocket" approach may be considered 2

Follow-up

• Refer patients to cardiology or electrophysiology within 1-2 weeks after initial presentation 2
• Monitor for recurrence after initial conversion
• Teach patients proper vagal maneuver techniques for home use 2

This algorithmic approach to PSVT management prioritizes treatments with the highest efficacy and safety profiles, with consideration for both acute termination and long-term prevention of recurrence.