What is the management of Supraventricular Tachycardia (SVT) for Family Nurse Practitioner (FNP) boards?

From the Guidelines

For the management of Supraventricular Tachycardia (SVT), the initial approach should include vagal maneuvers, and if these fail, adenosine should be administered as the first-line pharmacological treatment. SVT is a rapid heart rhythm originating above the ventricles, typically presenting with sudden onset palpitations, heart rates of 150-250 beats per minute, and possible symptoms of chest pain, dizziness, or shortness of breath 1. The initial management includes vagal maneuvers such as the Valsalva maneuver or carotid sinus massage to stimulate the vagus nerve and slow conduction through the AV node.

Key Points for Management

• Vagal maneuvers alone (Valsalva maneuver or carotid sinus massage) will terminate up to 25% of PSVTs 1.
• If vagal maneuvers fail, the first-line pharmacological treatment is adenosine, administered as a rapid IV push at 6 mg initially, followed by 12 mg if needed, with a possible third dose of 12 mg.
• For hemodynamically unstable patients, synchronized cardioversion at 50-100 joules is indicated.
• Long-term management may include calcium channel blockers like diltiazem or beta-blockers such as metoprolol 1.
• For recurrent SVT, catheter ablation may be considered, especially given its high success rate and the potential for definitive cure without the need for chronic pharmacological therapy 1.

Ongoing Management

• Oral beta blockers, diltiazem, or verapamil is useful for ongoing management in patients with symptomatic SVT who do not have ventricular pre-excitation during sinus rhythm 1.
• EP study with the option of ablation is useful for the diagnosis and potential treatment of SVT, providing the potential for definitive cure without the need for chronic pharmacological therapy 1.
• Patients with SVT should be educated on how to perform vagal maneuvers for ongoing management of SVT, which can help terminate SVT and reduce the need to seek medical attention 1.

From the FDA Drug Label

Adenosine injection is indicated as an adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately The recommended dose is 0.14 mg/kg/min infused over six minutes as a continuous peripheral intravenous infusion

SVT Treatment with Adenosine

• Adenosine is used for the treatment of supraventricular tachycardia (SVT)
• The dose for SVT is typically 6-12 mg IV given as a rapid bolus, which may be repeated as needed
• However, the provided drug labels do not explicitly state the dose for SVT treatment, only the dose for myocardial perfusion scintigraphy
• Key Considerations:
  • Contraindications: second- or third-degree AV block, sinus node disease, bronchoconstrictive lung disease, and known hypersensitivity to adenosine
  • Warnings: cardiac arrest, ventricular arrhythmias, sinoatrial and atrioventricular nodal block, bronchoconstriction, hypotension, cerebrovascular accidents, seizures, and hypersensitivity
• Given the information provided, it appears that adenosine may be used for SVT treatment, but the exact dosing and administration may vary depending on the specific clinical scenario 2, 2

From the Research

SVT Diagnosis and Management

• SVT is a common cause of hospital admissions and can cause significant patient discomfort and distress 3
• The most common SVTs include atrioventricular nodal re-entrant tachycardia, atrioventricular re-entrant tachycardia, and atrial tachycardia 3
• Diagnosis can be made using electrocardiography during tachycardia, comparing it with sinus rhythm, and assessing the onset and offset of tachycardia 3

Treatment Options

• Vagal maneuvers and adenosine are first-line therapies in the acute diagnosis and management of SVT 3, 4
• Alternative therapies include the use of beta-blockers and calcium channel blockers 3, 5, 6
• Adenosine and verapamil are equally effective in converting out-of-hospital SVT to sinus rhythm 7
• Calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine without the negative short-term side effects 6

Long-term Management

• Long-term treatment is dependent on several factors including frequency of symptoms, risk stratification, and patient preference 3
• Management can range from conservative, if symptoms are rare and the patient is low risk, to catheter ablation which is curative in the majority of patients 3, 5
• Catheter ablation has a success rate of 95% and recurrence rate of less than 5% 5

Special Considerations

• AVNRT is the most common tachydysrhythmia in pregnancy, and vagal maneuvers and adenosine are first line 6
• Electrical cardioversion should be utilized for hemodynamically unstable patients 6
• Most patients with AVNRT may be discharged with appropriate follow-up 6