What are the treatment options for supraventricular tachycardia (SVT)?

Treatment Options for Supraventricular Tachycardia (SVT)

The first-line treatment for SVT is vagal maneuvers, followed by adenosine administration if vagal maneuvers fail, and synchronized cardioversion for hemodynamically unstable patients or when pharmacological therapy is ineffective. 1, 2

Acute Management Algorithm

Step 1: Vagal Maneuvers (First-Line)

• Perform vagal maneuvers with the patient in a supine position 1, 2
• Valsalva maneuver: Have patient bear down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg) 1
• Modified Valsalva maneuver is superior with 43.7% success rate compared to 24.2% for standard Valsalva 3
• Carotid sinus massage: Apply steady pressure over carotid sinus for 5-10 seconds after confirming absence of bruits 1, 2
• Cold stimulus: Apply ice-cold wet towel to face (based on diving reflex) 1
• Switching between techniques can increase overall success rate to 27.7% 1, 2

Step 2: Pharmacological Treatment (If Vagal Maneuvers Fail)

• Adenosine (Class I recommendation): First-line drug for hemodynamically stable patients with 91-95% effectiveness 1, 2, 4
• Calcium channel blockers (Class IIa recommendation): Intravenous diltiazem or verapamil are highly effective for converting AVNRT to sinus rhythm in hemodynamically stable patients 1, 2
• Beta-blockers (Class IIa recommendation): Alternative for hemodynamically stable patients, though less effective than calcium channel blockers 1, 2

Step 3: Synchronized Cardioversion

• Indicated for hemodynamically unstable patients when vagal maneuvers and adenosine fail or aren't feasible 1
• Also recommended for hemodynamically stable patients when pharmacological therapy is ineffective or contraindicated 1
• Highly effective in terminating SVT 1

Special Considerations

Pre-excited AF (Wolff-Parkinson-White Syndrome)

• Synchronized cardioversion is first-line for hemodynamically unstable patients 1, 2
• Ibutilide or intravenous procainamide are recommended for hemodynamically stable patients 1, 2
• AVOID AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation as they may accelerate ventricular rate and lead to ventricular fibrillation 2

Long-term Management

• Catheter ablation is highly effective (94.3-98.5% success rate) and recommended as first-line therapy to prevent recurrence 4
• Flecainide can be used for prevention of paroxysmal SVT in patients without structural heart disease 5
• Long-term pharmacotherapy options include calcium channel blockers, beta-blockers, and antiarrhythmic agents 4, 6

Important Caveats and Pitfalls

• Never apply pressure to the eyeball as this practice is dangerous and has been abandoned 1, 2
• Carotid massage should only be performed after confirming absence of carotid bruits 1, 2
• Proper ECG diagnosis is essential before treatment to distinguish SVT from ventricular tachycardia 2
• Flecainide can cause proarrhythmic effects, including new or worsened supraventricular or ventricular arrhythmias 5
• Flecainide should not be used in patients with recent myocardial infarction or structural heart disease 5
• AV nodal blocking agents should be avoided in patients with suspected pre-excited AF, ventricular tachycardia, or systolic heart failure 2