What is the management of Paroxysmal Supraventricular Tachycardia (PSVT)?

Management of Paroxysmal Supraventricular Tachycardia (PSVT)

For acute PSVT management, start with vagal maneuvers followed immediately by adenosine 6 mg IV rapid push if vagal maneuvers fail, and proceed to synchronized cardioversion for hemodynamically unstable patients. 1, 2

Acute Management Algorithm

Hemodynamically Stable Patients

First-Line Interventions:

• Perform vagal maneuvers immediately - specifically the Valsalva maneuver (forceful exhalation against closed airway for 10-30 seconds at 30-40 mmHg pressure) with patient supine, or apply ice-cold wet towel to face to trigger diving reflex 1, 2
• Vagal maneuvers terminate 25-27.7% of PSVT episodes 1, 2

Second-Line Pharmacologic Treatment:

• Adenosine 6 mg IV rapid push through large vein, followed by 20 mL saline flush - this is the drug of choice with 90-95% conversion success rate 1, 2
• If no response, give adenosine 12 mg IV rapid push 2
• Minor side effects occur in ~30% but last <1 minute 1
• Critical warning: Have cardioversion equipment immediately available as adenosine may precipitate atrial fibrillation with rapid ventricular response or even ventricular fibrillation 1

Third-Line Options (if adenosine fails or contraindicated):

• Intravenous diltiazem or verapamil - effective in 80-98% of cases 1, 2
• Intravenous beta blockers are reasonable but less effective than diltiazem 1, 2

Hemodynamically Unstable Patients

Immediate synchronized cardioversion is mandatory when vagal maneuvers or adenosine are ineffective or not feasible 1, 2

• Start with 50-100 J biphasic energy 2
• Increase energy stepwise if initial shock fails 2
• Provide adequate sedation/anesthesia for stable patients before cardioversion 1

Special Consideration: Pre-excited Atrial Fibrillation (Wolff-Parkinson-White Syndrome)

Critical distinction: If patient has WPW with pre-excited AF, management differs completely:

• Hemodynamically unstable: Immediate synchronized cardioversion 1, 2
• Hemodynamically stable: Use ibutilide or IV procainamide - these slow accessory pathway conduction and may terminate AF 1, 2
• NEVER use AV nodal blocking agents (adenosine, beta blockers, calcium channel blockers, digoxin) in pre-excited AF as they can enhance accessory pathway conduction and precipitate ventricular fibrillation 1, 2

Long-Term Management Strategy

First-Line Definitive Therapy

Catheter ablation with electrophysiology study is the preferred first-line therapy for recurrent symptomatic PSVT 1, 2, 3

• Single procedure success rates: 94.3-98.5% 3
• Low complication rates 1, 2
• Provides definitive cure without need for chronic medications 1
• Particularly important for patients in safety-sensitive occupations (pilots, bus drivers) 1

Pharmacologic Management (when ablation declined or not feasible)

First-Line Medications:

• Oral beta blockers, diltiazem, or verapamil for patients without ventricular pre-excitation 1, 2
• Verapamil studied at doses up to 480 mg/day with documented reduction in episode frequency and duration 1
• All three medication classes showed similar efficacy in reducing SVT episodes 1

Second-Line Medications (for patients without structural/ischemic heart disease):

• Flecainide (100-300 mg/day) or propafenone (450-900 mg/day) are reasonable alternatives 1, 4, 5
• 12-month effective treatment probability: 86% for propafenone, 93% for flecainide 1
• Absolute contraindication in structural heart disease or ischemic heart disease due to proarrhythmia risk 1, 4
• FDA-approved specifically for prevention of PSVT in patients without structural heart disease 4, 5

Third-Line Options:

• Sotalol may be reasonable and can be used in structural heart disease (unlike flecainide/propafenone) 1
• Dofetilide may be considered when other agents fail or are contraindicated 1
• Amiodarone may be considered as last resort when all other options exhausted 1

Patient Education Component

All patients must be taught proper vagal maneuver technique for self-management 1, 2

• Perform in supine position 1
• Valsalva: forceful exhalation against closed airway for 10-30 seconds 1
• Ice-water immersion of face as alternative 1
• This education may reduce need for emergency department visits and shorten episode duration 1

Critical Pitfalls to Avoid

Pre-excitation screening is mandatory before starting calcium channel blockers or beta blockers - review baseline ECG for delta waves indicating WPW syndrome 2

Do not use flecainide or propafenone without excluding structural heart disease - obtain echocardiogram if any doubt, as these drugs carry proarrhythmic risk in structural disease 1, 4

Anticipate post-conversion arrhythmias - atrial or ventricular premature complexes immediately after adenosine or cardioversion may reinitiate tachycardia, requiring antiarrhythmic pretreatment 1

Adenosine administration technique matters - must use large vein with rapid push followed immediately by saline flush, or drug will be metabolized before reaching heart 2