What are the management options for a patient with paroxysmal supraventricular tachycardia (PSVT)?

Management of Paroxysmal Supraventricular Tachycardia (PSVT)

For acute PSVT, perform vagal maneuvers immediately, followed by adenosine 6 mg IV if unsuccessful; for long-term management, catheter ablation is the definitive first-line therapy with 94-98% success rates, while oral beta blockers, diltiazem, or verapamil serve as alternatives for patients who decline or cannot access ablation. 1, 2

Acute Management Algorithm

Step 1: Assess Hemodynamic Stability

Hemodynamically unstable patients require immediate synchronized cardioversion at 50-100 J without attempting vagal maneuvers or medications. 1, 2 Instability is defined by hypotension, altered mental status, signs of shock, chest pain, or acute heart failure 2. If the initial shock fails, increase energy stepwise 1.

Step 2: Hemodynamically Stable Patients

For stable patients, proceed sequentially through the following interventions:

First-Line: Vagal Maneuvers

• Perform vagal maneuvers with the patient in the supine position as the immediate first intervention. 3, 1
• The modified Valsalva maneuver (bearing down against a closed glottis for 10-30 seconds at 30-40 mmHg) terminates 27-43% of PSVT episodes 3, 2
• Alternative techniques include carotid sinus massage (after confirming absence of bruit, apply steady pressure for 5-10 seconds) or applying an ice-cold wet towel to the face 3, 1
• Carotid massage should be avoided in elderly patients (>65 years) due to higher risk of cerebrovascular disease 4

Second-Line: Adenosine

• If vagal maneuvers fail, administer adenosine 6 mg IV rapid push through a large vein, followed immediately by 20 mL saline flush. 1, 2
• Adenosine terminates approximately 90-95% of AVNRT and orthodromic AVRT 3, 1, 2
• If the first dose fails, give 12 mg IV rapid push as a second dose 1
• Critical contraindications: severe bronchial asthma and patients with pre-excitation (Wolff-Parkinson-White syndrome) who have atrial fibrillation. 1
• Adenosine may precipitate atrial fibrillation in 1-15% of patients, which is particularly dangerous in those with accessory pathways 1

Third-Line: Calcium Channel Blockers or Beta Blockers

• Intravenous diltiazem or verapamil are highly effective alternatives for patients who fail or are contraindicated for adenosine. 3, 1, 5
• Verapamil produces peak therapeutic effects within 3-5 minutes and converts approximately 60-80% of PSVT cases 5, 6
• Never use calcium channel blockers or beta blockers in patients with suspected ventricular tachycardia, pre-excited atrial fibrillation, or systolic heart failure, as this can cause hemodynamic collapse or ventricular fibrillation. 3, 2
• Intravenous beta blockers (such as esmolol or metoprolol) are reasonable but less effective than diltiazem 3, 1
• Extreme caution with concomitant IV calcium channel blockers and beta blockers due to potentiation of hypotensive/bradycardic effects. 1

Fourth-Line: Synchronized Cardioversion

• If pharmacologic therapy fails or the patient begins to decompensate, proceed immediately to synchronized cardioversion 3, 2

Long-Term Management Strategy

First-Line: Catheter Ablation

Electrophysiological study with catheter ablation is the definitive first-line therapy for recurrent symptomatic PSVT, offering potential cure without chronic medication. 3, 1, 2 Large registry studies demonstrate:

• Single-procedure success rates of 94.3-98.5% for AVNRT and AVRT 3, 2
• Low complication rates (see Table 8 in guidelines) 3
• Particularly indicated for patients with frequent episodes, occupational requirements (pilots, bus drivers), or those preferring definitive cure 3

Second-Line: Pharmacological Therapy

For patients who decline ablation, lack access to electrophysiology services, or have infrequent episodes:

Oral beta blockers, diltiazem (up to 480 mg/day), or verapamil (up to 480 mg/day) are first-line pharmacological options for ongoing management in patients without ventricular pre-excitation. 3, 1

• These agents reduce SVT episode frequency and duration 3
• All three medications demonstrate similar efficacy and tolerability 3

Flecainide or propafenone are reasonable second-line options for patients without structural heart disease or ischemic heart disease. 3, 1

Patient Education Component

All patients should be educated on proper vagal maneuver technique for self-management of acute episodes. 3, 1 This includes:

• Modified Valsalva maneuver technique (forcefully exhaling against closed airway for 10-30 seconds) 3
• Applying ice-cold wet towel to face 3
• Instructions to seek emergency care immediately if signs of hemodynamic instability develop 1

Critical Special Considerations

Wolff-Parkinson-White Syndrome with Pre-Excited Atrial Fibrillation

This is a life-threatening emergency requiring different management:

• For unstable patients: immediate synchronized cardioversion 1, 2
• For stable patients: IV ibutilide or procainamide 1, 2
• Absolutely avoid AV nodal blocking agents (adenosine, beta blockers, calcium channel blockers, digoxin) as these can accelerate ventricular rate and precipitate ventricular fibrillation. 1, 2

Common Pitfalls to Avoid

• Never assume wide-complex tachycardia is SVT with aberrancy; treat as ventricular tachycardia until proven otherwise 2
• Obtain a 12-lead ECG immediately to confirm narrow-complex tachycardia before administering AV nodal blockers 2, 7
• Monitor for atrial or ventricular premature complexes after conversion, as they may trigger recurrence 1
• Verapamil should not be used in patients with severe conduction abnormalities, sinus node dysfunction, or suspected systolic heart failure 3

Post-Conversion Management

After successful acute conversion, arrange cardiology follow-up for consideration of catheter ablation 2. An antiarrhythmic drug may be required temporarily to prevent acute reinitiation 2.