Treatment of Supraventricular Tachycardia (SVT)
The treatment of SVT should follow a stepwise approach, beginning with vagal maneuvers (particularly modified Valsalva maneuver) as first-line therapy, followed by adenosine if vagal maneuvers fail, and progressing to calcium channel blockers, beta blockers, or synchronized cardioversion for refractory cases, with catheter ablation recommended for long-term management of recurrent symptomatic SVT. 1
Acute Management Algorithm
First-Line Treatment
- Vagal Maneuvers (Class I, Level B-R) 1
- Modified Valsalva maneuver is most effective with 43% efficacy 2 and superior to standard Valsalva or carotid sinus massage 3
- Should be performed with patient in supine position
- Technique: Have patient perform strain (like blowing against resistance) for 15 seconds, then immediately lie flat with legs elevated
Second-Line Treatment
- Adenosine (Class I, Level B-R) 1
- Indicated if vagal maneuvers fail
- Initial dose: 6 mg IV rapid bolus
- Success rate approximately 91% 2
- Follow with saline flush and arm elevation for optimal delivery
Third-Line Treatment
IV Calcium Channel Blockers (Class IIa, Level B-R) 1
IV Beta Blockers (Class IIa, Level C-LD) 1
- Options: Esmolol, metoprolol, atenolol, propranolol
- Less effective than calcium channel blockers but excellent safety profile
Emergency Treatment
- Synchronized Cardioversion (Class I, Level B-NR) 1
- Immediate treatment of choice for hemodynamically unstable SVT
- Do not delay for medication administration if patient is unstable
Chronic Management Options
Definitive Treatment
- Catheter Ablation (Class I, Level B-NR) 1
Pharmacologic Options
AV Nodal Blockers (Class I, Level B-R) 1
- For patients without ventricular pre-excitation
- Options: Oral beta blockers, diltiazem, verapamil
Class IC Antiarrhythmics (Class IIa, Level B-R) 1
- Options: Flecainide, propafenone
- Only for patients without structural heart disease or ischemic heart disease
- Contraindicated in patients with structural heart disease or recent MI
Ivabradine (Class IIa, Level B-R) 1
- Dosage: 2.5-7.5 mg twice daily
- Shown to be effective for ongoing management
Special Considerations
Hemodynamic Status
- Stable Patients: Follow stepwise approach starting with vagal maneuvers
- Unstable Patients: Proceed directly to synchronized cardioversion 1, 5
Pregnancy
- Adenosine is safe due to short half-life 1
- Use lowest recommended medication doses
- Avoid medications in first trimester if possible
Contraindications and Cautions
- Do not use vagal maneuvers in hypotensive patients 1
- Avoid flecainide and propafenone in structural heart disease 1
- Monitor closely when administering amiodarone IV due to hypotension risk 1
- Verapamil is contraindicated in patients with WPW syndrome and atrial fibrillation 4
Follow-up Care
- Cardiology referral within 1-2 weeks after initial presentation 1
- Consider electrophysiology study for definitive diagnosis and treatment
- Monitor patients on medication therapy for side effects and efficacy
- Patient education on proper vagal maneuver techniques for home use
Common Pitfalls to Avoid
- Delaying cardioversion in hemodynamically unstable patients
- Using verapamil in patients with accessory pathways (can cause ventricular fibrillation)
- Failing to refer for definitive treatment with catheter ablation
- Inadequate follow-up after initial SVT episode
- Using Class IC antiarrhythmics in patients with structural heart disease
The treatment approach for SVT has evolved significantly, with strong evidence supporting the efficacy of modified Valsalva maneuver as the optimal vagal technique 3 and catheter ablation as the most effective long-term solution 2. While pharmacologic options provide symptomatic relief, they do not offer the curative potential of ablation.