From the Guidelines
The most effective treatment for Supraventricular Tachycardia (SVT) is to start with vagal maneuvers, such as the Valsalva maneuver or carotid sinus massage, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. This approach is supported by the fact that vagal maneuvers can be performed quickly and have a high success rate in terminating SVT.
- The Valsalva maneuver involves raising intrathoracic pressure by bearing down against a closed glottis for 10 to 30 seconds, equivalent to at least 30 to 40 mm Hg.
- Carotid massage is performed after absence of bruit has been confirmed by auscultation, by applying steady pressure over the right or left carotid sinus for 5 to 10 seconds. If vagal maneuvers are unsuccessful, adenosine is the recommended first-line medication for acute treatment of SVT, with a success rate of 90% to 95% in converting orthodromic AVRT to sinus rhythm 1.
- Adenosine is typically given as a rapid IV bolus of 6 mg, followed by 12 mg if needed, and another 12 mg dose if the arrhythmia persists. For ongoing management, calcium channel blockers (verapamil 5-10 mg IV or diltiazem 0.25 mg/kg IV) or beta-blockers (metoprolol 5 mg IV) can be effective in controlling the heart rate and preventing recurrence of SVT 1. In hemodynamically unstable patients, immediate synchronized cardioversion at 50-100 joules is recommended to rapidly restore sinus rhythm and prevent further complications 1. For long-term management, options include daily medications such as beta-blockers, calcium channel blockers, or antiarrhythmics like flecainide, or catheter ablation, which offers a definitive cure with success rates exceeding 95% for most SVT types.
- The choice of treatment depends on the specific type of SVT, frequency of episodes, patient preferences, and comorbidities. It is essential to note that SVT occurs due to abnormal electrical conduction pathways or automaticity in the atria or AV node, and targeting these mechanisms effectively terminates the arrhythmia.
- Therefore, the treatment approach should be individualized based on the underlying mechanism of the SVT and the patient's clinical presentation.
From the FDA Drug Label
In patients without structural heart disease, flecainide acetate tablets, USP are indicated for the prevention of: •paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism associated with disabling symptoms
Treatment for SVT: Flecainide acetate tablets, USP are indicated for the prevention of paroxysmal supraventricular tachycardias (PSVT) in patients without structural heart disease.
- The use of flecainide acetate tablets, USP should be reserved for patients in whom the benefits of treatment outweigh the risks 2.
- It is essential to follow the recommended dosage schedule to minimize the risk of proarrhythmic events 2.
From the Research
Treatment Options for SVT
- Vagal manoeuvres are a common first-line treatment for supraventricular tachycardia (SVT), with the Valsalva manoeuvre being a widely used technique 3, 4, 5, 6.
- The Valsalva manoeuvre has been shown to be effective in terminating SVT in approximately 19.4% to 54.3% of cases 4, 5, 6.
- Carotid sinus massage is another vagal manoeuvre that can be used to treat SVT, with a success rate of around 10.5% to 14.0% 5, 6.
- There is no significant difference in efficacy between the Valsalva manoeuvre and carotid sinus massage in terminating SVT 5, 6.
Pharmacological Treatment
- Calcium channel blockers, such as verapamil and diltiazem, can be used to treat SVT, especially in cases where vagal manoeuvres are unsuccessful 7.
- Slow infusion of verapamil and diltiazem has been shown to be effective in terminating SVT, with success rates of 98.8% and 96.3%, respectively 7.
- The dose of medication required to convert SVT varies, with verapamil requiring a lower dose than diltiazem 7.