In a 74‑year‑old woman with paroxysmal nonsustained ventricular tachycardia, hypertension, dyslipidemia, recurrent upper gastrointestinal bleeds from erosive esophagitis, hepatitis C, gastroesophageal reflux disease, daily smoking, and a prior transient ischemic attack on apixaban (Eliquis) 5 mg twice daily, who remains symptomatic with focal atrial tachycardia/palpitations despite metoprolol succinate 200 mg daily and declines invasive procedures, what is the recommended medical management?

Medical Management of Refractory Focal Atrial Tachycardia in a High-Risk Patient

Adding diltiazem 120 mg daily to metoprolol succinate 200 mg daily is reasonable for ongoing management of symptomatic focal atrial tachycardia, though this combination requires close monitoring for hypotension and excessive bradycardia. 1

Rationale for Combination Therapy

The 2015 ACC/AHA/HRS guidelines support your approach:

• Oral beta-blockers (metoprolol) and calcium channel blockers (diltiazem or verapamil) are Class IIa recommendations for ongoing management of symptomatic focal atrial tachycardia. 1 These agents are moderately effective with a low incidence of significant adverse effects, though data are limited to observational studies. 1

• Beta-blockers are most effective for controlling ventricular response during supraventricular arrhythmias and have been shown to accelerate conversion to sinus rhythm compared with diltiazem alone. 1 However, single-agent therapy at maximum tolerated dose (metoprolol 200 mg daily) has failed in this patient.

• Combination therapy with beta-blockers and calcium channel blockers may improve overall efficacy rates when single agents are insufficient. 1 In inappropriate sinus tachycardia (a related condition), the addition of ivabradine to metoprolol resolved symptoms in all patients in one small study, demonstrating that dual AV nodal suppression can be effective. 1

Critical Safety Monitoring

Close monitoring is essential when combining these agents:

• Monitor for hypotension, excessive bradycardia, and heart block. 1, 2 The combination potentiates negative chronotropic and dromotropic effects on the AV node.

• Avoid combining IV formulations of beta-blockers and calcium channel blockers acutely due to additive negative inotropic effects and increased risk of severe bradycardia. 3 However, oral combination therapy is more commonly tolerated.

• Check thyroid function as planned – hyperthyroidism can cause refractory focal atrial tachycardia and would alter management. 4

Alternative and Adjunctive Considerations

Antiarrhythmic Agents (Class IIa-IIb)

If combination rate control remains inadequate:

• Flecainide or propafenone (Class IIa) can be effective for ongoing management in patients without structural heart disease or ischemic heart disease. 1 Given her TIA history and vascular risk factors, careful assessment for structural heart disease is warranted before considering these agents. Flecainide dosing starts at 50 mg twice daily, increased by 50 mg increments every 4 days to maximum 300 mg/day for paroxysmal supraventricular arrhythmias. 5

• Oral sotalol or amiodarone (Class IIb) may be reasonable but carry higher risk of proarrhythmia and other complications. 1 The balance between anticipated benefit and potential adverse effects must be carefully considered.

Catheter Ablation Remains Optimal

Catheter ablation is a Class I recommendation for symptomatic focal atrial tachycardia as an alternative to pharmacological therapy. 1 Success rates exceed 90-95% in experienced centers with complication rates <1-2%. 1 While she currently declines invasive procedures, this should be revisited if:

• Medical therapy fails to control symptoms
• Tachycardia-mediated cardiomyopathy develops (occurs in up to 10% of patients with incessant focal AT) 1
• Quality of life remains significantly impaired

Addressing the Nonsustained Ventricular Tachycardia

The paroxysmal NSVT documented on her 7-day Holter requires separate consideration:

• NSVT in patients with structural heart disease is a prognostic indicator of increased mortality risk. 6 Her vascular risk factors (hypertension, dyslipidemia, smoking, TIA) suggest possible underlying coronary disease.

• Beta-blockers provide dual benefit – controlling both the focal atrial tachycardia and offering prognostic benefit if underlying ischemic or structural heart disease exists. 1, 7 Metoprolol has established mortality benefit in patients with heart disease. 8, 7

• If NSVT becomes more frequent or symptomatic, consider cardiology evaluation for possible electrophysiology study and risk stratification, particularly if ejection fraction is <35%. 1

Managing Anticoagulation Risk

Her continued Eliquis 5 mg twice daily is appropriate given the TIA history, but warrants ongoing vigilance:

• The combination of anticoagulation and history of multiple upper GI bleeds from erosive esophagitis creates significant bleeding risk. Ensure aggressive GERD management continues and consider gastroenterology follow-up for reassessment of esophagitis severity.

• No atrial fibrillation or flutter was documented on 7-day Holter, but focal atrial tachycardia can occasionally progress to atrial fibrillation. The anticoagulation provides coverage for both stroke prevention post-TIA and potential future atrial fibrillation.

Addressing Anxiety as a Trigger

Her report that palpitations worsen with anxiety is clinically significant:

• Beta-blockers are particularly effective for stress-related and anxiety-triggered tachycardia. 4 The current metoprolol dose should help, but anxiety management may reduce breakthrough episodes.

• Consider referral to her PCP or behavioral health for anxiety management, as she has been unable to discuss this due to increased anxiety. Non-pharmacologic interventions may reduce arrhythmia burden.

Common Pitfalls to Avoid

• Do not abruptly discontinue beta-blockers if side effects occur – taper to avoid rebound tachycardia and hypertension. 4

• Do not use adenosine for focal atrial tachycardia in the outpatient setting – it has only Class IIa recommendation for acute diagnosis and may terminate some triggered forms, but is not appropriate for ongoing management. 1, 2

• Avoid cardioversion for asymptomatic or minimally symptomatic focal AT until correction of underlying problems, as it is unlikely to result in long-term sinus rhythm. 1

• Monitor for tachycardia-mediated cardiomyopathy – if she develops heart failure symptoms or reduced ejection fraction, this would mandate more aggressive rhythm control, likely requiring ablation. 1

Smoking Cessation is Critical

Her continued daily smoking significantly increases cardiovascular risk and may exacerbate arrhythmias through catecholamine release. Smoking cessation should be strongly encouraged at every visit as it impacts both her arrhythmia burden and overall cardiovascular prognosis.