In a 37-year-old woman with intermittent exertional shortness of breath, palpitations, dizziness, diaphoresis, rapid symptom resolution at rest, a normal heart rate, normotensive blood pressure, an unremarkable cardiac exam, and an ECG showing a narrow‑complex paroxysmal supraventricular tachycardia, what is the most appropriate treatment?

Treatment of Paroxysmal Supraventricular Tachycardia in a Young Woman

For this 37-year-old woman with paroxysmal supraventricular tachycardia (likely AVNRT based on her presentation), catheter ablation is the most appropriate treatment, offering a 94-98% single-procedure success rate and definitive cure without the need for lifelong medications. 1

Rationale for Catheter Ablation as First-Line Therapy

Catheter ablation should be recommended as first-line definitive therapy for this patient because:

• She has recurrent symptomatic episodes occurring over several years, indicating this is not a self-limited condition 2
• Her symptoms are significantly impacting quality of life (exertional limitation, palpitations, dizziness, diaphoresis) 1
• She is young (37 years old) and would otherwise require decades of pharmacotherapy with associated side effects and incomplete symptom control 3
• Ablation has exceptional success rates of 94.3-98.5% for AVNRT with minimal complications 1
• The procedure provides a curative solution rather than symptom management 4, 5

Clinical Context: AVNRT Diagnosis

This presentation is classic for atrioventricular nodal reentrant tachycardia (AVNRT), the most common form of SVT:

• AVNRT occurs in >60% of women, typically young adults without structural heart disease 2
• Characteristic symptoms include sudden-onset palpitations, shortness of breath, dizziness, and neck pulsations 2
• Episodes are often triggered by exertion and resolve spontaneously with rest 2
• The narrow-complex tachycardia on ECG with normal baseline exam confirms the diagnosis 2, 1

Acute Management Options (If Needed During Episodes)

While catheter ablation is the definitive treatment, acute episode management includes:

First-Line Acute Therapy

• Vagal maneuvers (modified Valsalva maneuver for 10-30 seconds, carotid massage for 5-10 seconds, or ice-cold towel to face) are Class I recommendations and should be attempted first 2
• Intravenous adenosine is 91% effective for acute conversion and is the pharmacologic agent of choice if vagal maneuvers fail 2, 1

Alternative Acute Pharmacotherapy

• IV diltiazem or verapamil (Class IIa) if adenosine is contraindicated or ineffective 2
• IV beta-blockers (Class IIa) as an alternative 2

Why Long-Term Pharmacotherapy is Suboptimal

Chronic medical therapy should be considered second-line for several important reasons:

• Evidence for long-term pharmacotherapy effectiveness in preventing PSVT recurrence is limited 1
• Beta-blockers, calcium channel blockers (diltiazem, verapamil), and antiarrhythmic agents provide incomplete symptom control 3, 2
• Medications require lifelong adherence with potential side effects 3
• Amiodarone is specifically designated as second-line due to significant toxicity with long-term use 3
• Digoxin receives only a Class IIb recommendation (may be reasonable) and carries toxicity risks, reserved only for patients who cannot take other agents 3

Common Pitfalls to Avoid

• Do not delay referral to electrophysiology: All patients with SVT should receive heart rhythm specialist consultation 4
• Do not assume pharmacotherapy is adequate: Given her young age and recurrent symptoms over years, she will likely experience breakthrough episodes and medication side effects
• Do not overlook quality of life impact: Her exertional symptoms are limiting daily activities, which catheter ablation can definitively resolve
• Ensure proper acute management education: While awaiting ablation, teach her vagal maneuvers for self-management of acute episodes 2

Procedural Considerations

The electrophysiology study and ablation procedure:

• Allows precise diagnosis of the SVT mechanism through diagnostic maneuvers 3
• Uses multielectrode catheters with or without 3D electroanatomic mapping to localize the reentry circuit 3
• Has rare but potentially life-threatening complications, though overall safety profile is excellent 3, 1
• Provides immediate and durable results in the vast majority of patients 1