What is the recommended beta blocker (beta-adrenergic blocking agent) for supraventricular tachycardia (SVT)?

Recommended Beta Blockers for Supraventricular Tachycardia (SVT)

Intravenous metoprolol is the recommended beta blocker for acute treatment of SVT, while oral metoprolol is recommended for ongoing management of SVT. 1

Acute Management of SVT

First-line treatments (in order):

1. Vagal maneuvers - First attempt to terminate SVT 1
2. Intravenous adenosine - First-line pharmacological therapy 1
3. Intravenous beta blockers, diltiazem, or verapamil - When adenosine fails 1
   • Metoprolol IV is specifically mentioned in guidelines for SVT treatment 1

Beta blocker selection for acute SVT:

• Metoprolol IV is the preferred beta blocker mentioned in guidelines 1
• Propranolol IV is an alternative, particularly in pregnant patients 1

Special considerations:

• In hemodynamically unstable patients, synchronized cardioversion is recommended rather than medications 1
• Beta blockers should be avoided in patients with:
  • Severe bronchospastic pulmonary disease
  • Decompensated heart failure
  • Severe conduction abnormalities
  • Sinus node dysfunction 1

Ongoing Management of SVT

First-line treatments:

1. Catheter ablation - Recommended as definitive treatment with >95% success rate 1
2. Oral medications - For patients who are not candidates for or prefer not to undergo ablation:
   • Oral beta blockers (Class I recommendation) 1
   • Oral diltiazem or verapamil (Class I recommendation) 1

Beta blocker selection for chronic SVT:

• Metoprolol is specifically mentioned in guidelines for ongoing management 1
• Propranolol has been studied at doses of 240 mg/day 1
• Atenolol has shown efficacy in long-term management at doses of 0.7 mg/kg/day (median effective dose) 2

Second-line options:

If beta blockers, diltiazem, or verapamil are ineffective or contraindicated:

• Flecainide or propafenone (in patients without structural heart disease) 1
• Sotalol (combines beta-blocking and Class III antiarrhythmic properties) 1
• Dofetilide or amiodarone (for refractory cases) 1

Type-Specific SVT Recommendations

For AVNRT (AV Nodal Reentrant Tachycardia):

• Acute: IV metoprolol, diltiazem, or verapamil (Class IIa) 1
• Chronic: Oral metoprolol or other beta blockers (Class I) 1

For AVRT (AV Reentrant Tachycardia):

• Similar approach as AVNRT with beta blockers as first-line therapy 1

For MAT (Multifocal Atrial Tachycardia):

• IV metoprolol can be useful for acute treatment (Class IIa) 1
• Oral metoprolol is reasonable for ongoing management (Class IIa) 1

Clinical Pearls and Pitfalls

• Dosing: For metoprolol, typical IV dose is 5 mg slow IV push, which can be repeated up to 3 times; oral dosing typically ranges from 25-100 mg twice daily
• Contraindications: Never use beta blockers in patients with pre-excited AF (can increase risk of ventricular fibrillation) 1
• Pregnancy: Beta-1-selective blockers (like metoprolol) are preferred over non-selective agents during pregnancy, but all beta blockers can cause fetal bradycardia 1
• Monitoring: When using beta blockers, monitor for bradycardia, hypotension, and heart block
• Combination therapy: In some cases, combining a beta blocker with another agent may be more effective than monotherapy

In summary, metoprolol is the preferred beta blocker for both acute and chronic management of SVT based on current guidelines, with other beta blockers serving as alternatives based on specific patient characteristics and comorbidities.