What are the management options for Supraventricular Tachycardia (SVT)?

Management of Supraventricular Tachycardia (SVT)

Catheter ablation is the most effective first-line therapy for recurrent, symptomatic SVT, with success rates of 94-98% and should be offered to all eligible patients with symptomatic SVT. 1, 2

Acute Management Algorithm

Hemodynamically Unstable Patients

1. Synchronized cardioversion (Class I, Level B-NR) is the immediate treatment of choice for hemodynamically unstable SVT when vagal maneuvers or adenosine are ineffective or not feasible 1

Hemodynamically Stable Patients

1. Vagal maneuvers (Class I, Level B-R) - First-line treatment 1, 2

   • Modified Valsalva maneuver is most effective (43% effective) 3
   • Should be performed with patient in supine position
   • Techniques include:
     • Forceful exhalation against closed airway for 10-30 seconds (30-40 mmHg)
     • Application of ice-cold wet towel to face (diving reflex)
     • Quickly lying backward from seated position 4

2. Adenosine (Class I, Level B-R) - If vagal maneuvers fail 1, 2

   • Initial dose: 6 mg IV rapid bolus
   • If ineffective after 1-2 minutes: 12 mg IV bolus
   • Success rate approximately 91% 3

3. IV calcium channel blockers (Class IIa, Level B-R) - If adenosine fails 1

   • Diltiazem or verapamil
   • Administer as slow infusion (up to 20 minutes) to reduce hypotension risk
   • Conversion rate approximately 60% within 10 minutes
   • Contraindicated in suspected VT, pre-excited AF, or systolic heart failure

4. IV beta blockers (Class IIa, Level C-LD) - Alternative to calcium channel blockers 1

   • Options include esmolol, metoprolol, atenolol, propranolol
   • Less effective than calcium channel blockers but have excellent safety profile

5. Synchronized cardioversion (Class I, Level B-NR) - If pharmacological therapy is ineffective or contraindicated 1

Long-Term Management Options

First-Line Option

• Catheter ablation (Class I, Level B-NR) 1, 2, 5
  • Success rates of 94-98% for AVNRT and AVRT
  • Low complication rates
  • Provides potential cure without need for chronic medications
  • Particularly recommended for:
    • Recurrent symptomatic SVT
    • Patients in certain occupations (pilots, bus drivers)
    • Wolff-Parkinson-White syndrome

Pharmacological Options (if ablation not preferred/available)

1. AV nodal blockers (Class I, Level B-R) 1, 2

   • For patients without ventricular pre-excitation during sinus rhythm
   • Options:
     • Oral beta blockers (propranolol up to 240 mg/day)
     • Diltiazem
     • Verapamil (up to 480 mg/day)

2. Class IC antiarrhythmics (Class IIa, Level B-R) 1, 6, 7

   • For patients without structural heart disease or ischemic heart disease
   • Options:
     • Flecainide (100-300 mg/day)
     • Propafenone (450-900 mg/day)
   • CAUTION: Contraindicated in patients with structural heart disease or recent myocardial infarction due to proarrhythmic risk

3. Other antiarrhythmics (if above options ineffective/contraindicated)

   • Sotalol (Class IIb, Level B-R) 1
   • Dofetilide (Class IIb, Level B-R) 1
   • Amiodarone (Class IIb, Level C-LD) - last resort due to side effect profile 1, 2
   • Ivabradine (Class IIa, Level B-R) - 2.5-7.5 mg twice daily 2

4. Oral digoxin (Class IIb, Level C-LD) - May be reasonable but less effective than other options 1

Special Considerations

1. Patient education

   • Teach proper vagal maneuver techniques to terminate episodes at home
   • Explain warning signs requiring medical attention

2. Pregnancy

   • Adenosine is safe due to short half-life
   • Use lowest recommended medication doses
   • Avoid medications in first trimester if possible

3. End-stage renal disease

   • Monitor for electrolyte abnormalities
   • Be aware of dialysis-related fluid shifts triggering arrhythmias

Follow-up Recommendations

• Cardiology referral within 1-2 weeks after initial presentation
• Consider electrophysiology study for definitive diagnosis and treatment
• Monitor patients on medication therapy for side effects and efficacy

Common Pitfalls to Avoid

1. Delaying cardioversion in hemodynamically unstable patients
2. Using verapamil or diltiazem in patients with suspected VT or pre-excited AF
3. Prescribing flecainide or propafenone to patients with structural heart disease
4. Attempting vagal maneuvers in hypotensive patients
5. Failing to refer patients for definitive treatment with catheter ablation