What is the most appropriate treatment for a 37-year-old female with intermittent shortness of breath on exertion, palpitations, dizziness, diaphoresis, and tachycardia, but no chest pain, with an electrocardiogram (EKG) showing abnormal results and blood pressure indicating hypotension?

Management of Paroxysmal Supraventricular Tachycardia in a Young Female

This patient's presentation is most consistent with paroxysmal supraventricular tachycardia (PSVT), likely atrioventricular nodal reciprocating tachycardia (AVNRT), and the most appropriate initial treatment is beta-blocker therapy with metoprolol or similar agents for long-term prophylaxis, combined with patient education on vagal maneuvers for acute episode termination. 1

Clinical Diagnosis

The clinical picture strongly suggests PSVT, specifically AVNRT, based on several key features:

• Paroxysmal nature of attacks with intermittent episodes over several years, which is highly characteristic of sinus node re-entry or AVNRT 1
• Classic symptom constellation of palpitations, dizziness, diaphoresis, and shortness of breath during exertion, with complete resolution at rest 1
• Demographics: AVNRT is more prevalent in females and typically presents with palpitations, dizziness, and is not usually associated with structural heart disease 1
• Tachycardia rate of 90 bpm at rest after an episode, with rates during attacks typically between 140-250 bpm for AVNRT 1
• Absence of chest pain makes acute coronary syndrome less likely, though this must still be excluded 1

Immediate Evaluation Required

Before initiating definitive therapy, certain evaluations are essential:

• Serial troponin measurements at 6-12 hours from symptom onset to exclude myocardial injury, as a single measurement is insufficient 2, 3
• Repeat ECG if symptoms recur, as dynamic ECG changes can indicate high-risk acute coronary syndrome even with initially normal findings 2, 3
• Echocardiography to exclude structural heart disease, valvular abnormalities, or mitral valve prolapse, which can present with similar symptoms 1

Acute Episode Management

For termination of acute episodes:

• Vagal maneuvers (Valsalva, carotid massage) are first-line for acute termination, as AVNRT characteristically responds to these interventions 1
• Adenosine administration is highly effective for acute termination if vagal maneuvers fail 1
• Patient education on self-administered vagal maneuvers is critical for empowering patients to manage future episodes 1

Long-Term Prophylactic Treatment

Beta-blockers are the cornerstone of chronic management for symptomatic PSVT:

• Metoprolol is appropriate for patients with frequent or poorly tolerated episodes, addressing both the tachyarrhythmia and associated adrenergic symptoms 1
• Initiate at low doses (25-50 mg twice daily) with gradual titration based on symptom control and heart rate response 4
• Alternative agents include nondihydropyridine calcium-channel blockers (diltiazem, verapamil), amiodarone, or digoxin if beta-blockers are contraindicated 1

Lifestyle Modifications

Before escalating pharmacologic therapy:

• Cessation of stimulants including caffeine, alcohol, and cigarettes may be sufficient to control symptoms in many cases 1
• Avoidance of triggers such as dehydration, sleep deprivation, and excessive physical exertion should be emphasized 1

When to Consider Advanced Intervention

Electrophysiological study and radiofrequency catheter ablation are indicated for:

• Frequent or poorly tolerated episodes that do not adequately respond to drug therapy 1
• Patients preferring definitive cure over chronic medical management 1
• Uncertainty about tachycardia mechanism where electrophysiological studies would guide appropriate therapy 1
• Radiofrequency ablation success rates are generally high for persistent sinus node re-entry tachycardias and AVNRT 1

Critical Pitfalls to Avoid

• Do not dismiss symptoms in young females without structural heart disease, as AVNRT is the most common form of PSVT in this demographic 1
• Never abruptly discontinue beta-blocker therapy once initiated, as this can precipitate rebound tachycardia and worsen symptoms 4
• Avoid relying on single troponin measurements drawn less than 6 hours from symptom onset, as myocardial injury may not yet be detectable 2, 3
• Do not overlook psychological factors including panic disorder and anxiety, which commonly coexist with MVP and can exacerbate palpitations 1

Monitoring and Follow-Up

• Continuous or event-activated ambulatory ECG recordings may reveal the presence or absence of arrhythmias during symptomatic episodes and guide treatment adjustments 1
• Serial clinical assessment of symptom frequency, severity, and impact on quality of life should guide therapy escalation 1
• Reassess need for electrophysiological study if medical therapy fails to provide adequate symptom control after 3-6 months 1