What are the management strategies for Supraventricular Tachycardia (SVT), Paroxysmal Supraventricular Tachycardia (PSVT), and Atrial Fibrillation (AF)?

Management of SVT, PSVT, and Atrial Fibrillation

Acute Management of SVT/PSVT

For hemodynamically stable patients with SVT/PSVT, initiate vagal maneuvers immediately (modified Valsalva maneuver has 43% success rate), followed by intravenous adenosine (91% effective) if vagal maneuvers fail, while for hemodynamically unstable patients, proceed directly to synchronized cardioversion. 1, 2

Acute Treatment Algorithm for Stable Patients

First-line interventions:

• Modified Valsalva maneuver or diving reflex activation should be attempted first 2
• If vagal maneuvers fail, administer adenosine 6 mg rapid IV bolus, followed by 12 mg boluses (up to two additional doses) if needed 1, 3
• Adenosine terminates 90-95% of orthodromic AVRT and is effective in 85-100% of PSVT involving the AV node 1, 3

Second-line pharmacotherapy if adenosine fails:

• Intravenous diltiazem or verapamil are recommended alternatives 1
• Verapamil converts 86% of patients who fail vagal maneuvers 4
• Intravenous beta blockers can be considered 1

Critical caveat for pre-excitation (WPW):

• Never use AV nodal blocking agents (verapamil, diltiazem, beta blockers, digoxin) in patients with pre-excited atrial fibrillation as they may enhance accessory pathway conduction and precipitate ventricular fibrillation 1
• For pre-excited AF in stable patients, use ibutilide or intravenous procainamide 1, 5

Acute Treatment for Unstable Patients

Synchronized cardioversion is the definitive treatment for any hemodynamically unstable patient with SVT/PSVT, regardless of mechanism. 1, 5, 2

• Cardioversion should be performed immediately without delay for pharmacologic trials 1
• Have cardioversion equipment readily available even when using adenosine, as it may precipitate AF with rapid ventricular response 1

Long-Term Management of SVT/PSVT

Catheter ablation is the first-line definitive therapy for preventing recurrent PSVT, with single-procedure success rates of 94.3-98.5% and low complication rates, particularly for AVNRT and AVRT. 1, 2

Treatment Selection Strategy

Catheter ablation indications:

• Recommended as first-line therapy for symptomatic patients with recurrent PSVT 1, 2
• Cost-effectiveness analysis favors ablation over medical therapy for patients with monthly episodes 1
• Success rates exceed 90% for common SVT types (AVNRT, AVRT) 1

Pharmacologic prevention (when ablation declined or contraindicated):

• Flecainide 50 mg twice daily (can increase to 100 mg twice daily, maximum 300 mg/day for PSVT) is FDA-approved for prevention of PSVT in patients without structural heart disease 6
• Beta blockers or calcium channel blockers (diltiazem, verapamil) are alternative options 1
• Avoid flecainide in patients with structural heart disease, recent MI, or significant ventricular dysfunction 6

"Pill-in-the-pocket" approach:

• Self-administered single-dose therapy can be developed in partnership with patients for acute episodes 1
• Requires shared decision-making and patient education 1

Management of Atrial Fibrillation

AF management differs fundamentally from PSVT and requires anticoagulation assessment, rate/rhythm control decisions, and consideration of ablation for symptomatic paroxysmal AF, though chronic AF management is not adequately addressed in SVT guidelines. 1, 7

Anticoagulation Strategy

Stroke risk stratification determines anticoagulation need:

• Warfarin (target INR 2.0-3.0) is recommended for AF patients at high stroke risk (age >75, prior stroke/TIA, heart failure, hypertension, diabetes) 7
• For persistent or paroxysmal AF with intermediate risk (age 65-75 without other risk factors), either warfarin or aspirin 325 mg daily 7
• Anticoagulation decisions for AF are independent of rate/rhythm control strategy 7

Rate vs. Rhythm Control

The SVT guidelines explicitly state that chronic AF management is not adequately studied and specific recommendations are not provided. 6

• Flecainide is FDA-approved for prevention of paroxysmal AF with disabling symptoms in patients without structural heart disease 6
• Flecainide should not be used in chronic AF 6

Catheter Ablation for AF

• Early ablation for atrial flutter significantly reduces hospital utilization and AF risk 1
• AF ablation is more complex than PSVT ablation and requires specialized expertise 1

Special Populations

Adult Congenital Heart Disease (ACHD)

ACHD patients require specialized management with pediatric/congenital cardiology collaboration, as acute success rates are lower (70-85%) with higher recurrence (20-60% within 2 years). 1

• Acute antithrombotic therapy aligns with AF guidelines 1
• Intravenous adenosine, diltiazem, or esmolol (with caution for hypotension) for stable patients 1
• Avoid flecainide in ACHD patients with significant ventricular dysfunction 1

Pregnancy

Pregnant patients with SVT have increased arrhythmia susceptibility but safe treatment options exist, with vagal maneuvers and adenosine preferred acutely. 1

• Avoid medications in first trimester when possible due to teratogenicity risk 1
• Use lowest effective doses with regular monitoring 1

Adolescents

Adolescent patients (age 14-17) require immediate referral to pediatric cardiology/electrophysiology, as adult guidelines do not provide pediatric-specific dosing or management recommendations. 8

• Teach vagal maneuvers while awaiting cardiology evaluation 8
• Never initiate pharmacotherapy without specialist input due to significant pediatric dosing differences 8
• Expedited referral (1-2 weeks) for frequent episodes; urgent referral (within days) for pre-excitation concern 8

Key Pitfalls to Avoid

Common dangerous errors:

• Using AV nodal blockers in pre-excited AF (can cause ventricular fibrillation) 1, 5
• Initiating flecainide in patients with structural heart disease or recent MI (proarrhythmic risk) 6
• Assuming all SVTs are benign without determining specific mechanism 8
• Performing carotid massage in elderly patients (>65 years) with potential cerebrovascular disease—proceed directly to verapamil 4
• Delaying cardioversion in hemodynamically unstable patients while attempting pharmacologic conversion 1, 5