What are the management options for Paroxysmal Supraventricular Tachycardia (PSVT)?

Management of Paroxysmal Supraventricular Tachycardia (PSVT)

Vagal maneuvers followed by adenosine are the first-line treatments for acute management of PSVT, while catheter ablation is the most effective long-term solution for recurrent symptomatic PSVT. 1

Acute Management Algorithm

Hemodynamically Unstable Patients

• Immediate synchronized cardioversion is recommended for patients with hemodynamically unstable PSVT when vagal maneuvers or adenosine are ineffective or not feasible 1
• Initial energy settings for cardioversion of SVT: 50-100 J (biphasic) 1
• If initial shock fails, increase energy in a stepwise fashion 1

Hemodynamically Stable Patients

1. First-line: Vagal maneuvers

   • Valsalva maneuver: patient bears down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) in supine position 1
   • Carotid sinus massage: apply steady pressure over right or left carotid sinus for 5-10 seconds after confirming absence of carotid bruit 1
   • Modified Valsalva (head down deep breathing) can be effective in some cases 2
   • Vagal maneuvers alone terminate up to 25% of PSVTs 1

2. Second-line: Adenosine

   • Initial dose: 6 mg IV rapid push through large vein followed by 20 mL saline flush 1
   • If no response within 1-2 minutes, give 12 mg IV rapid push 1
   • Effectiveness: approximately 91% successful in terminating PSVT 3
   • Cautions:
     • Have defibrillator available when administering to patients with suspected WPW 1
     • Reduce initial dose to 3 mg in patients taking dipyridamole or carbamazepine, those with transplanted hearts, or if given by central venous access 1
     • Contraindicated in asthma patients 1
     • May require larger doses in patients with significant blood levels of theophylline, caffeine, or theobromine 1

3. Third-line: Calcium channel blockers

   • Intravenous diltiazem or verapamil can be effective for acute treatment in hemodynamically stable patients 1, 4
   • Advantages over adenosine: longer half-life, lower cost, and lower probability of re-initiating arrhythmia 4
   • Caution: avoid in patients with suspected WPW syndrome with pre-excitation as it may accelerate ventricular rate and lead to ventricular fibrillation 1

4. Fourth-line: Beta blockers

   • Intravenous beta blockers are reasonable for acute treatment in hemodynamically stable patients 1
   • Though less effective than diltiazem in terminating SVT, they have an excellent safety profile 1

Long-Term Management Options

Catheter Ablation

• First-line therapy for recurrent symptomatic PSVT 1, 3
• Electrophysiological study with ablation is useful for diagnosis and definitive treatment 1
• High success rates (94.3-98.5%) with low complication rates 3
• Provides potential cure without need for chronic pharmacological therapy 1

Pharmacological Management

For patients who are not candidates for or prefer not to undergo catheter ablation:

1. First-line pharmacological options:

   • Oral beta blockers, diltiazem, or verapamil for symptomatic patients without ventricular pre-excitation 1
   • These medications slow conduction through the AV node, reducing episode frequency and duration 1

2. Second-line pharmacological options:

   • Flecainide or propafenone for patients without structural heart disease or ischemic heart disease 1, 5, 6
   • FDA approved for prevention of PSVT 5, 6
   • Caution: These drugs have proarrhythmic effects and should not be used in patients with structural heart disease 1

3. Third-line pharmacological options:

   • Sotalol may be reasonable for symptomatic patients 1
   • Dofetilide may be reasonable when first and second-line medications are ineffective or contraindicated 1
   • Amiodarone may be considered when other options are ineffective or contraindicated 1
   • Digoxin may be reasonable for symptomatic patients without pre-excitation 1

Special Considerations

Pre-excited AF in WPW Syndrome

• Synchronized cardioversion for hemodynamically unstable patients 1
• Ibutilide or intravenous procainamide for hemodynamically stable patients 1
• Avoid AV nodal blocking agents (adenosine, beta blockers, calcium channel blockers, digoxin) as they may enhance conduction through accessory pathway and precipitate ventricular fibrillation 1

Patient Education

• Patients should be educated on proper technique for performing vagal maneuvers for self-management of PSVT episodes 1
• This can help avoid prolonged tachycardia episodes and reduce the need for medical attention 1

Common Pitfalls to Avoid

• Misdiagnosing the mechanism of tachycardia (record 12-lead ECG) 1
• Administering verapamil or diltiazem in patients with WPW and pre-excited AF 1
• Applying pressure to eyeballs (dangerous and abandoned practice) 1
• Delaying cardioversion in hemodynamically unstable patients 1
• Using flecainide or propafenone in patients with structural heart disease 1, 5