What is the treatment for Supraventricular Tachycardia (SVT)?

Treatment of Supraventricular Tachycardia (SVT)

For acute management of SVT, vagal maneuvers should be attempted first, followed by adenosine if unsuccessful, and synchronized cardioversion for hemodynamically unstable patients. 1, 2

Acute Management Algorithm

Step 1: Hemodynamic Assessment

• Quickly determine if the patient is hemodynamically stable or unstable 1, 2

Step 2: Treatment Based on Hemodynamic Status

For Hemodynamically Stable Patients:

1. Vagal Maneuvers (First-Line) 1, 2

   • Perform in supine position 2
   • Valsalva maneuver: Patient bears down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) 1
   • Modified Valsalva maneuver: More effective with 43% success rate 3, 4
   • Carotid sinus massage: Apply steady pressure over carotid sinus for 5-10 seconds (after confirming absence of carotid bruit) 1, 2
   • Cold stimulus: Apply ice-cold wet towel to face 1
   • Success rate increases to 27.7% when switching between techniques 1, 2

2. Adenosine (Second-Line) 1

   • Highly effective (91-95% success rate) 2, 3
   • Rapid onset and brief duration of action 5
   • Monitor for common side effects: chest discomfort, dyspnea, flushing (typically short-lived) 5
   • Be prepared for potential induction of atrial fibrillation 1

3. Other Pharmacologic Options 1, 2

   • Intravenous calcium channel blockers (diltiazem, verapamil): Particularly effective for AVNRT 1, 2
   • Intravenous beta-blockers: Reasonable alternative but less effective than calcium channel blockers 1, 2

For Hemodynamically Unstable Patients:

• Immediate synchronized cardioversion when adenosine and vagal maneuvers don't terminate the tachycardia or aren't feasible 1

Special Considerations:

• For pre-excited AF (WPW syndrome):
  • Synchronized cardioversion for hemodynamically unstable patients 1
  • Ibutilide or IV procainamide for hemodynamically stable patients 1, 2
  • AVOID AV nodal blocking agents (verapamil, diltiazem, beta-blockers) as they may accelerate ventricular rate and lead to ventricular fibrillation 2

Long-term Management

First-Line: Catheter Ablation

• Recommended as first-line therapy for recurrent SVT 3, 6
• Highly effective with success rates of 94.3-98.5% 3
• Particularly recommended for AVNRT due to low risk of AV block 6

Pharmacologic Options:

• Oral beta-blockers, diltiazem, or verapamil for symptomatic patients without ventricular pre-excitation 1
• Flecainide or propafenone for patients without structural heart disease who are not candidates for ablation 1, 7
  • CAUTION: Flecainide can cause proarrhythmic effects, especially in patients with structural heart disease or recent myocardial infarction 7
• Sotalol may be reasonable for symptomatic patients not undergoing ablation 1
• Dofetilide may be considered when other medications are ineffective or contraindicated 1
• Amiodarone may be considered as a last resort when other options have failed 1

Important Pitfalls and Caveats

• NEVER apply pressure to eyeballs - this practice is dangerous and abandoned 1, 2
• Always confirm absence of carotid bruits before carotid sinus massage 1, 2
• Ensure proper ECG diagnosis before treatment to distinguish SVT from ventricular tachycardia 2
• Avoid AV nodal blocking agents in patients with suspected pre-excitation 2
• Monitor for tachycardia-mediated cardiomyopathy (rare but serious complication) 3
• Flecainide should not be used in patients with recent myocardial infarction or structural heart disease 7