What is the emergency treatment for supraventricular (SV) tachycardia?

From the Guidelines

The emergency treatment for supraventricular tachycardia (SVT) begins with vagal maneuvers, such as the Valsalva maneuver or carotid sinus massage, which can terminate the arrhythmia by increasing parasympathetic tone. If these fail, intravenous adenosine is the first-line medication, typically administered as a rapid bolus of 6 mg, followed by a 12 mg dose if needed, and another 12 mg dose if the arrhythmia persists, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. Adenosine works by temporarily blocking AV node conduction, interrupting the reentry circuit responsible for SVT. For patients with contraindications to adenosine (such as asthma or heart transplant recipients), calcium channel blockers like verapamil (5-10 mg IV) or diltiazem (0.25 mg/kg IV) can be used, as supported by the guideline 1. Beta-blockers such as metoprolol (5 mg IV) are also effective alternatives.

Key Considerations

• Vagal maneuvers should be performed with the patient in the supine position, and there is no "gold standard" for proper Valsalva maneuver technique, but in general, the patient raises intrathoracic pressure by bearing down against a closed glottis for 10 to 30 seconds, equivalent to at least 30 mm Hg to 40 mm Hg 1.
• Adenosine may also be useful diagnostically, to unmask atrial flutter or AT, but it is uncommon for adenosine to terminate these atrial arrhythmias, as noted in the guideline 1.
• In hemodynamically unstable patients presenting with hypotension, altered mental status, or chest pain, immediate synchronized cardioversion at 50-100 joules is indicated, as recommended by the guideline 1.
• After the acute episode is controlled, patients should be evaluated for long-term management options, which may include catheter ablation or maintenance medications to prevent recurrence.

Treatment Options

• Vagal maneuvers: Valsalva maneuver or carotid sinus massage
• Intravenous adenosine: 6 mg rapid bolus, followed by 12 mg dose if needed, and another 12 mg dose if the arrhythmia persists
• Calcium channel blockers: verapamil (5-10 mg IV) or diltiazem (0.25 mg/kg IV)
• Beta-blockers: metoprolol (5 mg IV)
• Synchronized cardioversion: 50-100 joules for hemodynamically unstable patients

Important Notes

• The practice of applying pressure to the eyeball is potentially dangerous and has been abandoned, as noted in the guideline 1.
• The safety and effectiveness of cardioversion in the prehospital setting was analyzed in a cohort of patients with hemodynamically unstable SVT who had failed to convert with vagal maneuvers and intravenous pharmacological therapy, and cardioversion successfully restored sinus rhythm in all patients, as reported in the guideline 1.

From the FDA Drug Label

ADENOSINE INJECTION, USP for intravenous use Initial U. S. Approval: 1995 INDICATIONS AND USAGE Adenosine Injection, a pharmacologic stress agent, is indicated as an adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately ( 1)

DOSAGE AND ADMINISTRATION Recommended dose is 0.14 mg/kg/min infused over six minutes as a continuous peripheral intravenous infusion (total dose of 0. 84 mg/kg) ( 2)

The emergency treatment for supraventricular (SV) tachycardia is adenosine (IV), administered as a 0.14 mg/kg/min infusion over six minutes as a continuous peripheral intravenous infusion, with a total dose of 0.84 mg/kg 2.

From the Research

Emergency Treatment for Supraventricular Tachycardia

The emergency treatment for supraventricular (SV) tachycardia involves several options, including:

• Vagal maneuvers as the first-line treatment for stable patients 3
• Adenosine or calcium channel antagonists (CCAs) when vagal maneuvers fail 4, 5, 6, 7
• Synchronized cardioversion for unstable patients, although this may not always be feasible or accepted by the patient 5
• Digoxin as an alternative in resource-limited settings or when other treatments are not available or acceptable 5

Treatment Options

The following treatment options are available for SV tachycardia:

• Adenosine: effective but with a significant side-effect profile, including minor adverse events such as nausea, chest tightness, shortness of breath, and headache 4, 6, 7
• Calcium channel antagonists (CCAs): also effective but with a risk of hypotension 4, 6, 7
• Digoxin: may be used as an alternative in certain situations, but its use requires further investigation 5
• Vagal maneuvers: the most effective and safe vagal maneuver is the Valsalva maneuver, which can be modified to improve its efficacy 3

Considerations

When choosing a treatment option, the following factors should be considered:

• The patient's stability and acceptance of treatment options 5
• The potential side effects and risks associated with each treatment option 4, 6, 7
• The availability of resources and treatment options in the specific setting 5
• The need for further investigation into the use of certain treatments, such as digoxin 5