What is the acute management of symptomatic Supraventricular Tachycardia (SVT)?

From the Guidelines

The acute management of symptomatic supraventricular tachycardia (SVT) should begin with vagal maneuvers, such as the Valsalva maneuver or carotid sinus massage, as first-line treatment. If these are unsuccessful, adenosine is the drug of choice, administered as a rapid IV bolus of 6 mg, followed by a 12 mg dose if needed, and a second 12 mg dose if the arrhythmia persists, as recommended by the most recent guidelines 1. Adenosine works by temporarily blocking AV nodal conduction, often terminating the reentry circuit responsible for most SVTs.

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 2.
• Adenosine has been shown to effectively terminate SVT in approximately 95% of patients and will unmask atrial activity in arrhythmias, such as atrial flutter or AT 2.
• For patients with contraindications to adenosine (such as severe asthma or pre-excitation syndromes), or if adenosine fails, beta-blockers such as metoprolol (5 mg IV over 2-5 minutes, up to 3 doses) are also effective alternatives, as their strength of recommendation has been increased in the new guidelines 1.
• For 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 guidelines 2, 3.

Additional Options

• Other treatment options, such as calcium channel blockers like verapamil or diltiazem, have been downgraded in the new guidelines 1, and their use should be considered on a case-by-case basis.
• The new guidelines also recommend ivabradine, alone or in combination with beta-blockers, in symptomatic patients with inappropriate sinus tachycardia and postural orthostatic tachycardia syndrome 1.

Long-term Management

After acute termination, patients should be evaluated for underlying causes and considered for long-term management options, including catheter ablation for recurrent episodes. Proper ECG documentation before and after treatment is essential for diagnosis and future management planning.

From the Research

Acute Management of Symptomatic Supraventricular Tachycardia (SVT)

The acute management of symptomatic SVT involves several steps, including:

• Diagnostic evaluation to confirm the diagnosis, which may include a comprehensive history and physical examination, electrocardiography, and laboratory workup 4
• Identification of the type of SVT, as the management may vary depending on the type 5

Hemodynamically Unstable Patients

For patients who are hemodynamically unstable, the first-line management is:

• Synchronized cardioversion 4, 6

Hemodynamically Stable Patients

For patients who are hemodynamically stable, the first-line management is:

• Vagal maneuvers, such as the modified Valsalva maneuver 6
• If vagal maneuvers are ineffective, stepwise medication management may be used, including:
  • Adenosine 7, 6
  • Beta blockers and/or calcium channel blockers 4, 5, 8, 6

Long-term Management

Long-term management of SVT may involve:

• Catheter ablation, which is a highly effective and recommended therapy to prevent recurrence of PSVT 4, 5, 8, 6
• Pharmacotherapy, including calcium channel blockers, β-blockers, and antiarrhythmic agents, which may be used to prevent recurrence of SVT 4, 5, 8, 6