What is the algorithm for supraventricular tachycardia (SVT) treatment?

From the Guidelines

The treatment algorithm for supraventricular tachycardia (SVT) begins with vagal maneuvers like the Valsalva maneuver or carotid sinus massage as first-line interventions, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. If these fail, adenosine is the medication of choice, administered as a rapid IV bolus starting at 6 mg, followed by 12 mg if needed, and another 12 mg dose if the arrhythmia persists, with a success rate of 90% to 95% in terminating orthodromic AVRT 1. For patients with contraindications to adenosine, calcium channel blockers like verapamil or diltiazem are appropriate alternatives, with success rates of 80% to 98% in converting AVNRT to sinus rhythm 1. Beta-blockers such as metoprolol or esmolol can also be effective in terminating SVT, although evidence for their effectiveness is limited 1. For hemodynamically unstable patients, immediate synchronized cardioversion at 50-100 joules is indicated, as it is highly effective in terminating SVT and restoring sinus rhythm 1. Long-term management may include catheter ablation for definitive treatment or chronic medication with calcium channel blockers, beta-blockers, or antiarrhythmics like flecainide or propafenone. These treatments work by interrupting the reentry circuit that causes SVT, either by transiently blocking AV nodal conduction (adenosine), slowing conduction (calcium channel blockers, beta-blockers), or by directly terminating the arrhythmia through electrical cardioversion. Some key points to consider in the treatment of SVT include:

• Vagal maneuvers should be performed with the patient in the supine position, and carotid massage should be performed after absence of bruit has been confirmed by auscultation 1.
• Adenosine may precipitate AF that may then conduct rapidly to the ventricle and even cause ventricular fibrillation, so electrical cardioversion should be available 1.
• Synchronized cardioversion is highly effective in terminating SVT, including AVRT and AVNRT, and should be considered early in the management of hemodynamically unstable patients 1.

From the FDA Drug Label

Verapamil Hydrochloride Injection, USP is indicated for the following: • Rapid conversion to sinus rhythm of paroxysmal supraventricular tachycardias, including those associated with accessory bypass tracts (Wolff-Parkinson-White [W-P-W] and Lown-Ganong- Levine [L-G-L] syndromes). When clinically advisable, appropriate vagal maneuvers (e.g., Valsalva maneuver) should be attempted prior to verapamil hydrochloride administration.

The algorithm for SVT treatment may involve:

• Attempting vagal maneuvers (e.g., Valsalva maneuver) prior to administration of verapamil hydrochloride
• Administering verapamil hydrochloride for rapid conversion to sinus rhythm of paroxysmal supraventricular tachycardias 2 Note that propafenone is also used to reduce the rate of paroxysmal supraventricular arrhythmias (including PSVT), but the provided text does not describe a specific algorithm for SVT treatment using this medication 3

From the Research

Algorithm for SVT Treatment

The algorithm for supraventricular tachycardia (SVT) treatment involves several steps, including:

• Hemodynamically unstable patients with SVT should be treated with electrical cardioversion 4
• If the patient is stable, acute termination of tachycardia can be achieved by vagal maneuvers or medical therapy 4
• Vagal maneuvers, such as the Valsalva maneuver, carotid massage, and ice to the face, can be used to terminate SVT 4, 5, 6
• The Valsalva maneuver is a non-invasive means of increasing myocardial refractoriness by increasing intrathoracic pressure for a brief period, thus stimulating baroreceptor activity in the aortic arch and carotid bodies, resulting in increased parasympathetic (vagus nerve) tone 7
• The effectiveness of the Valsalva maneuver in terminating SVT has been studied, with reversion rates ranging from 19.4% to 54.3% 5, 6, 7

Vagal Maneuvers

Vagal maneuvers are simple and non-invasive, but yield positive results in less than half the cases 8

• The Valsalva maneuver and carotid sinus massage (CSM) are commonly used vagal maneuvers 5, 6
• The reverse Valsalva maneuver is a new technique that has been tested for the treatment of SVT, with encouraging results 8
• The Valsalva maneuver and CSM achieved conversion in a total of 41 instances of SVT (success rate 27.7%) 5, 6

Medical Therapy

Medical therapy can be used to terminate SVT if vagal maneuvers are unsuccessful 4

• Pharmacological agents, such as adenosine, can be used to increase the refractoriness of atrioventricular nodal tissue within the myocardium 7
• Electrical cardioversion can be used if medical therapy is unsuccessful or if the patient is hemodynamically unstable 4