What are the treatment options for supraventricular tachycardia (SVT)?

Treatment of Supraventricular Tachycardia (SVT)

The first-line treatment for acute SVT is vagal maneuvers, followed by adenosine administration if vagal maneuvers fail, and synchronized cardioversion for hemodynamically unstable patients or when pharmacological therapy is ineffective. 1

Acute Management Algorithm

Step 1: Vagal Maneuvers (First-Line)

• Perform in supine position with proper technique 1:
  • Valsalva maneuver: Patient bears down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg pressure) 1
  • Carotid sinus massage: After confirming absence of carotid bruit, apply steady pressure over right or left carotid sinus for 5-10 seconds 1
  • Modified Valsalva is more effective (43% success rate) than standard techniques 2
  • Cold stimulus: Applying ice-cold wet towel to face (diving reflex) 1
• Success rate of switching between techniques is approximately 27.7% 1

Step 2: Pharmacological Treatment (If Vagal Maneuvers Fail)

• For hemodynamically stable patients:
  • Adenosine (Class I recommendation): First-line drug with 91-95% effectiveness 1, 2
  • Calcium channel blockers (Class IIa): Intravenous diltiazem or verapamil are highly effective for converting AVNRT to sinus rhythm 1
  • Beta-blockers (Class IIa): Intravenous administration is reasonable but less effective than calcium channel blockers 1
  • Oral beta-blockers, diltiazem, or verapamil may be reasonable in stable patients (Class IIb) 1

Step 3: Synchronized Cardioversion

• For hemodynamically unstable patients when adenosine and vagal maneuvers fail or are not feasible (Class I recommendation) 1
• For hemodynamically stable patients when pharmacological therapy is ineffective or contraindicated (Class I recommendation) 1

Special Considerations

Pre-excited AF (Wolff-Parkinson-White Syndrome)

• Synchronized cardioversion should be performed for hemodynamically unstable patients (Class I) 1
• Ibutilide or intravenous procainamide for hemodynamically stable patients (Class I) 1
• CAUTION: Avoid AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation as they may accelerate ventricular rate and lead to ventricular fibrillation 1

Orthodromic AVRT

• Treatment algorithm similar to AVNRT 1
• Beta-blockers, diltiazem, or verapamil might be considered for patients with pre-excitation who haven't responded to other therapies (Class IIb) 1

Long-Term Management

• Catheter ablation is highly effective (94-98.5% success rate) and recommended as first-line therapy to prevent recurrence 2
• Pharmacological options include:
  • Beta-blockers, calcium channel blockers for symptom control 3, 2
  • Flecainide for prevention of paroxysmal SVT in patients without structural heart disease 4

Important Caveats and Pitfalls

• NEVER apply pressure to the eyeball - this practice is dangerous and has been abandoned 1
• Always confirm the absence of carotid bruits before performing carotid sinus massage 1
• Ensure proper ECG diagnosis before treatment - distinguish SVT from ventricular tachycardia 1
• Avoid calcium channel blockers and beta-blockers in patients with:
  • Suspected pre-excited AF 1
  • Ventricular tachycardia 1
  • Systolic heart failure 1
• Flecainide has proarrhythmic effects and should not be used in patients with structural heart disease, recent myocardial infarction, or chronic atrial fibrillation 4
• Monitor for proarrhythmic events when using antiarrhythmic medications 4