What is the best course of management for a 56-year-old female with HTN, DM2, HLD, asthma, and a smoking history, who presents with SVT and has recently started a new job as a caregiver, with elevated Troponin levels likely due to demand mismatch, and has been treated with IV Lopressor (Metoprolol) in the ER?

Management of First-Episode SVT with Elevated Troponin

Continue the beta-blocker (metoprolol) for ongoing management, complete the echocardiogram and 7-day Holter monitor as planned, then refer to electrophysiology for consideration of catheter ablation rather than discontinuing the beta-blocker. 1, 2

Rationale for Continuing Beta-Blocker Therapy

Oral beta-blockers are a Class I recommendation (highest level) for ongoing management of symptomatic SVT without ventricular pre-excitation. 1 The ACC/AHA/HRS guidelines specifically state that oral beta blockers, diltiazem, or verapamil are useful for ongoing management in patients with symptomatic SVT who do not have ventricular pre-excitation during sinus rhythm. 1

The proposed plan to "discontinue beta-blocker to evaluate for further episodes" contradicts guideline-based care for several reasons:

• Beta-blockers reduce SVT recurrence frequency and duration, making discontinuation counterproductive for a patient who just experienced her first symptomatic episode. 1
• The patient has multiple cardiovascular risk factors (HTN, DM2, HLD, smoking) that independently benefit from beta-blocker therapy, particularly given the elevated troponin suggesting demand ischemia. 3
• Discontinuing therapy to "wait for recurrence" exposes the patient to unnecessary risk of repeat episodes that could be prevented with appropriate prophylaxis. 1

Addressing the Elevated Troponin

The troponin elevation is appropriately attributed to demand mismatch from the sustained tachycardia at 204 bpm. 3 Research demonstrates that troponin elevation in SVT correlates directly with maximum heart rate during the episode (r = 0.637, P = 0.001), and most patients do not have significant coronary artery disease requiring intervention. 3

The planned echocardiogram is essential to:

• Rule out structural heart disease or cardiomyopathy
• Assess left ventricular ejection fraction
• Guide long-term management decisions 1, 2

Invasive coronary evaluation is not indicated unless the echocardiogram reveals concerning findings or the patient develops recurrent chest pain, given that troponin elevation in SVT without coronary disease is well-documented. 3

Optimal Discharge Plan

Immediate Management (24-48 hours):

• Continue telemetry monitoring until echocardiogram completed 1
• Maintain oral metoprolol at the dose that achieved rate control 1, 2
• Complete echocardiogram to assess for structural disease and guide therapy 1
• Educate patient on vagal maneuvers (Valsalva maneuver: forceful exhalation against closed airway for 10-30 seconds, or ice-cold wet towel to face) for potential future episodes 1

Post-Discharge Plan:

• 7-day Holter monitor as planned to assess for recurrent episodes and burden 1
• Outpatient cardiology follow-up within 1-2 weeks 1
• Electrophysiology referral should be the primary discussion, not beta-blocker discontinuation 1

Definitive Treatment Consideration

Electrophysiological study with catheter ablation is a Class I recommendation and should be offered as first-line definitive therapy. 1 The guidelines explicitly state that EP study with ablation is useful as first-line therapy for treatment of symptomatic SVT, providing potential for definitive cure without need for chronic pharmacological therapy. 1

Catheter ablation offers:

• High success rates (>90-95%) for both AVNRT and AVRT 1, 2
• Low complication rates 1
• Elimination of need for lifelong medication 1
• Particularly important for this patient given her new physically demanding job as a caregiver requiring stair climbing 1

Critical Safety Considerations

Before any consideration of beta-blocker discontinuation, the echocardiogram must confirm:

• No ventricular pre-excitation pattern (Wolff-Parkinson-White syndrome) on baseline ECG, as AV nodal blockers including beta-blockers are contraindicated in pre-excited atrial fibrillation 1, 2
• Preserved left ventricular function, though even reduced EF would support continued beta-blocker use 2, 4
• No structural heart disease requiring specific management 1

The patient's asthma requires careful monitoring on beta-blocker therapy, though cardioselective beta-blockers like metoprolol are generally well-tolerated. 2 If bronchospasm develops, calcium channel blockers (diltiazem or verapamil) are equally effective Class I alternatives. 1

Common Pitfall to Avoid

Do not discontinue effective prophylactic therapy to "see if SVT recurs." This outdated approach exposes patients to preventable morbidity. The modern guideline-based approach prioritizes either:

1. Continued medical therapy with proven efficacy (beta-blockers, calcium channel blockers) 1
2. Definitive cure with catheter ablation 1, 2

The choice between these options should be based on patient preference, symptom burden, occupation requirements, and access to electrophysiology services—not on arbitrary discontinuation of effective therapy. 1