From the Guidelines
Oral verapamil or diltiazem is recommended for ongoing management in patients with supraventricular tachycardia (SVT) who are not candidates for, or prefer not to undergo, catheter ablation. The management of SVT, specifically atrioventricular nodal reentrant tachycardia (AVNRT), involves several oral medication options. According to the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1, first-line treatment includes oral beta blockers, such as metoprolol, atenolol, or propranolol, which are effective in managing symptoms by slowing conduction through the AV node.
Key Medications for SVT Management
- Beta blockers: Metoprolol (25-100 mg twice daily), atenolol (25-100 mg daily), or propranolol (10-40 mg three to four times daily) are commonly used.
- Calcium channel blockers: Diltiazem (120-360 mg daily in divided doses) and verapamil (120-480 mg daily in divided doses) are recommended for patients who are not candidates for beta blockers or have specific indications for their use.
- Antiarrhythmic agents: Flecainide (50-200 mg twice daily) and propafenone (150-300 mg three times daily) may be considered for patients with recurrent SVT despite first-line therapy, but their use is limited by potential proarrhythmic effects and should be guided by the presence of structural heart disease or ischemic heart disease.
Considerations for Medication Choice
- The choice of medication should be tailored to the individual patient's condition, including the presence of structural heart disease, ischemic heart disease, and symptoms.
- Patients should be monitored for side effects, including fatigue, bronchospasm, and bradycardia with beta blockers, and constipation, hypotension, and edema with calcium channel blockers.
- The potential for proarrhythmic effects with antiarrhythmic medications necessitates careful patient selection and monitoring.
Additional Management Strategies
- Catheter ablation of the slow pathway is a highly effective treatment for AVNRT and is considered first-line therapy for symptomatic patients 1.
- Clinical follow-up without pharmacological therapy or ablation may be reasonable for minimally symptomatic patients with AVNRT, with education on when to seek medical attention and how to perform vagal maneuvers 1.
In summary, the management of SVT involves a stepwise approach, starting with vagal maneuvers and first-line oral medications like beta blockers and calcium channel blockers, with catheter ablation considered for symptomatic patients or those who fail medical therapy. The choice of medication and treatment strategy should prioritize minimizing morbidity, mortality, and improving quality of life, guided by the most recent and highest quality evidence available 1.
From the Research
Oral Medications for Outpatient Management of Supraventricular Tachycardia (SVT)
The following oral medications are recommended for the outpatient management of SVT:
Efficacy of Oral Medications
The efficacy of these oral medications in terminating SVT episodes has been demonstrated in several studies:
- Flecainide and diltiazem/propranolol combination: 61% and 94% conversion to sinus rhythm, respectively 2
- Metoprolol: restored sinus rhythm in 3 out of 6 patients with paroxysmal SVT 4
- Diltiazem and propranolol combination: terminated PSVT in 14 out of 15 patients 3
Safety and Tolerability
The safety and tolerability of these oral medications have also been evaluated:
- Flecainide and diltiazem/propranolol combination: well-tolerated with minimal side effects 2
- Metoprolol: effective and safe in patients with systolic blood pressure greater than 100 mm Hg 4
- Diltiazem and propranolol combination: transient second-degree atrioventricular block and junctional rhythm occurred in 2 patients 3
Drug Choice
The choice of oral medication depends on the correct diagnosis of the arrhythmia and an understanding of its mechanism 5. Drugs that are well-tolerated with minimal side effects are preferred over agents with perhaps more efficacy but higher risk of toxicity 5.