What is the management plan for a patient with a history of supraventricular tachycardia (SVT) who has been treated and is now in normal sinus rhythm?

Management of SVT After Conversion to Normal Sinus Rhythm

After successful conversion of SVT to normal sinus rhythm, obtain a 12-lead ECG immediately to identify pre-excitation patterns, then stratify management based on episode frequency: teach vagal maneuvers for infrequent episodes (1-2 per year) or initiate oral beta blockers, diltiazem, or verapamil for frequent episodes, with referral to cardiology for catheter ablation consideration in recurrent symptomatic cases. 1

Immediate Post-Conversion Assessment

Obtain a 12-lead ECG immediately after conversion to identify baseline abnormalities that reveal the SVT mechanism. 1 This is critical because:

• Pre-excitation patterns (delta waves) make calcium channel blockers and beta blockers contraindicated, as these agents may enhance accessory pathway conduction and precipitate ventricular fibrillation if atrial fibrillation develops. 2
• The ECG findings determine your entire management strategy going forward. 1

Risk Stratification by Episode Frequency

Infrequent Episodes (1-2 per year)

For patients with rare episodes, teach vagal maneuvers as the primary management strategy rather than initiating daily suppressive medications. 1 This includes:

• Modified Valsalva maneuver (bearing down for 15 seconds while supine, then lying flat with legs elevated). 1
• Carotid sinus massage (if no carotid bruits present). 1
• These techniques have a combined success rate of approximately 27.7% and empower patients to self-manage episodes. 1

Frequent Episodes (>2 per year)

Initiate oral beta blockers, diltiazem, or verapamil as first-line suppressive therapy (Class I recommendation). 2, 1 These medications work by slowing AV nodal conduction and have proven efficacy:

• Oral diltiazem or verapamil achieve 64-98% success rates for preventing SVT recurrence. 2, 1
• Beta blockers are equally appropriate as first-line agents, with choice depending on comorbidities (e.g., avoid beta blockers in asthma, avoid calcium channel blockers in systolic heart failure). 2

Definitive Treatment: Catheter Ablation

Refer for electrophysiologic study with catheter ablation as the preferred long-term management for patients with recurrent symptomatic SVT. 1, 3, 4 This is particularly important because:

• Catheter ablation has success rates of 94-98% and is potentially curative. 1, 3
• All patients treated for SVT should be referred for a heart rhythm specialist opinion to discuss ablation as a definitive option. 4
• Ablation is especially recommended for Wolff-Parkinson-White syndrome due to the risk of sudden death. 3, 5

Critical Contraindications and Pitfalls

Avoid calcium channel blockers and beta blockers in the following situations:

• Pre-excitation on ECG (delta waves indicating accessory pathway), as these agents may precipitate ventricular fibrillation if atrial fibrillation develops. 2, 1
• Severe conduction abnormalities or sinus node dysfunction, as these agents further slow conduction. 1
• Decompensated systolic heart failure, particularly with calcium channel blockers (diltiazem/verapamil). 2
• Hypotension, as both drug classes can worsen blood pressure. 1

Patient Education Components

Provide specific trigger avoidance counseling:

• Avoid caffeine, alcohol, stress, and fatigue, which commonly precipitate SVT episodes. 1
• Ensure patients can demonstrate proper vagal maneuver technique before discharge, as this empowers self-management. 1
• Educate patients to seek immediate care if episodes become prolonged, more frequent, or associated with chest pain or syncope. 3

Follow-Up Strategy

Schedule cardiology follow-up within 2-4 weeks to: 1

• Review ECG findings and assess for pre-excitation or other abnormalities. 1
• Assess response to suppressive therapy if initiated. 1
• Discuss definitive management options, particularly catheter ablation, which should be offered to most patients with recurrent symptomatic SVT. 1, 4
• Monitor for breakthrough episodes, medication side effects, and development of new conduction abnormalities. 1

Alternative Pharmacologic Options

For patients who cannot tolerate or fail first-line agents:

• Flecainide (Class IC antiarrhythmic) may be used for prevention of paroxysmal SVT in patients without structural heart disease, starting at 50 mg every 12 hours. 6
• Flecainide should be reserved for patients in whom benefits outweigh risks due to proarrhythmic effects, and should not be used in patients with recent myocardial infarction or structural heart disease. 6
• Initiation should occur with rhythm monitoring, and dosage increases should be made no more frequently than every four days. 6