What is the recommended management of a patient with supraventricular tachycardia?

Management of Supraventricular Tachycardia

For hemodynamically stable SVT, begin with vagal maneuvers followed immediately by adenosine if unsuccessful; for hemodynamically unstable patients, perform immediate synchronized cardioversion. 1, 2, 3

Acute Management Algorithm

Step 1: Assess Hemodynamic Stability

Hemodynamically unstable means the patient has hypotension, altered mental status, chest pain indicating ischemia, or signs of acute heart failure. 2

• If unstable: Perform immediate synchronized cardioversion after sedation if the patient is conscious. 1, 3 This restores sinus rhythm in nearly all patients. 3
• If stable: Proceed to Step 2.

Step 2: Obtain 12-Lead ECG and Initiate Vagal Maneuvers

• Record a 12-lead ECG immediately to confirm narrow-complex tachycardia and exclude ventricular tachycardia or pre-excited atrial fibrillation. 2, 3
• Perform vagal maneuvers as first-line therapy (Class I recommendation). 1, 2

Vagal maneuver techniques:

• Modified Valsalva maneuver: Patient bears down against a closed glottis for 10-30 seconds (equivalent to 30-40 mm Hg intrathoracic pressure) while supine. 1, 3 Success rate is approximately 43%. 2, 4
• Carotid sinus massage: Apply steady pressure over the carotid sinus for 5-10 seconds after confirming absence of bruit by auscultation. 1, 3 Avoid in elderly patients or those with carotid disease. 3
• Diving reflex: Apply an ice-cold wet towel to the face. 1, 3
• Rotating among different vagal maneuvers increases overall success to approximately 27.7%. 1, 3

Critical pitfall: Never use eyeball pressure—this technique is dangerous and has been abandoned. 1, 2, 3

Step 3: Administer Adenosine

• If vagal maneuvers fail, adenosine is the recommended first-line pharmacologic agent (Class I recommendation). 1, 2
• Adenosine terminates SVT in 90-95% of cases. 2, 3, 4
• Brief side effects (flushing, chest discomfort) occur in ~30% of patients and resolve within one minute. 3
• Have electrical cardioversion equipment immediately available because adenosine can precipitate rapid atrial fibrillation. 3

Step 4: Second-Line Pharmacologic Therapy

If adenosine fails or is contraindicated:

• Intravenous diltiazem or verapamil are highly effective alternatives (Class IIa recommendation), converting SVT in 64-98% of patients. 1, 2, 3 The FDA label confirms verapamil converts approximately 60-80% of supraventricular tachycardias to sinus rhythm within 10 minutes. 5
• Administer slowly over 20 minutes to reduce hypotension risk. 3
• Intravenous beta-blockers are reasonable second-line agents but slightly less effective than calcium channel blockers. 1, 3

Critical pitfall: Do NOT use calcium channel blockers (verapamil, diltiazem) if ventricular tachycardia or pre-excited atrial fibrillation is possible, as this can precipitate ventricular fibrillation and hemodynamic collapse. 2, 3 The FDA label specifically warns about life-threatening responses (<1%) including rapid ventricular rate in atrial flutter/fibrillation with an accessory bypass tract. 5

Additional critical pitfall: Never combine IV calcium channel blockers with IV beta-blockers due to potentiation of hypotensive and bradycardic effects. 2

Step 5: Synchronized Cardioversion for Refractory Cases

• When pharmacologic therapy fails or is contraindicated in stable patients, perform synchronized cardioversion with appropriate sedation. 1, 3
• Success rate is 80-98% when combined with prior drug therapy. 3

Post-Conversion Management

• Observe patients for approximately 4 hours with continuous cardiac monitoring after successful conversion. 2
• Be prepared for immediate recurrence of SVT after cardioversion or adenosine (due to premature atrial or ventricular complexes) and have antiarrhythmic drugs readily available. 3

Long-Term Management

For patients with recurrent symptomatic SVT:

• Catheter ablation should be considered for all patients as first-line definitive therapy. 2, 3, 4 Single-procedure success rates range from 94.3% to 98.5%. 3, 4
• If ablation is declined or unsuitable: Oral beta-blockers, diltiazem, or verapamil are appropriate first-line options for patients without ventricular pre-excitation. 2, 3
• In patients without structural heart disease or ischemic heart disease: Flecainide or propafenone are reasonable choices. 3
• Sotalol may be used when first-line agents fail. 3
• Dofetilide is an option when beta-blockers, calcium channel blockers, flecainide, and propafenone are ineffective or contraindicated. 3

Do NOT use digoxin acutely for SVT termination; reserve it only for selected cases of chronic management. 3

Patient Education

• Teach all patients how to perform vagal maneuvers (modified Valsalva, carotid massage, facial cooling) for self-management of SVT episodes. 3