How to manage A-fib in a patient with CAD, Sick Sinus Syndrome, and a pacemaker, on Metoprolol Tartrate, Digoxin, and Rivaroxaban, after an episode of RVR and bradycardia?

Management of Atrial Fibrillation in a Patient with CAD, Sick Sinus Syndrome, and Pacemaker

For this 67-year-old female with CAD, atrial fibrillation, sick sinus syndrome, and pacemaker, amiodarone should be used for rate control given her recent episode of RVR followed by bradycardia with metoprolol tartrate.

Current Situation Assessment

This patient presents with a complex cardiovascular profile:

• History of CAD and atrial fibrillation
• Sick sinus syndrome with pacemaker placement
• Recent hospitalization for atrial fibrillation with RVR
• Developed bradycardia after Cardizem (diltiazem) administration
• Currently on multiple medications including metoprolol tartrate 75mg BID, digoxin 0.25mg daily, and rivaroxaban 20mg daily

Optimal Rate Control Strategy

First-line Recommendation

• Amiodarone is the most appropriate agent for rate control in this patient given her complex cardiac history 1
• Amiodarone can be useful to control heart rate when other measures are unsuccessful or contraindicated (Class IIa recommendation) 1
• This patient has demonstrated intolerance to both beta-blockers (metoprolol) and calcium channel blockers (diltiazem)

Medication Adjustments

1. Discontinue metoprolol tartrate

   • Metoprolol should be avoided in patients with sick sinus syndrome due to risk of worsening bradycardia 2, 3
   • The patient already demonstrated bradycardia after rate control medication

2. Consider reducing or discontinuing digoxin

   • Digoxin can worsen bradycardia in patients with sick sinus syndrome 4
   • While effective for resting heart rate control in heart failure, it may contribute to her bradycardic episodes

3. Initiate amiodarone

   • Start with low-dose oral amiodarone (200mg daily after loading)
   • Amiodarone is recommended for rate control when other agents are unsuccessful or contraindicated 1
   • Monitor for drug interactions with digoxin (if continued) as amiodarone increases digoxin levels 1

Pacemaker Considerations

• Ensure pacemaker settings are optimized to prevent bradycardia while allowing appropriate rate control
• Consider reprogramming the pacemaker to a higher base rate to prevent symptomatic bradycardia
• AV node ablation with ventricular pacing may be reasonable if pharmacological therapy remains insufficient (Class IIa recommendation) 1

Anticoagulation Management

• Continue rivaroxaban 20mg daily
• This patient has multiple risk factors for stroke (age, female sex, CAD, atrial fibrillation)
• Anticoagulation should be maintained regardless of rhythm control success 2

Monitoring and Follow-up

• Monitor heart rate and rhythm closely after medication changes
• Assess for symptoms during both rest and activity
• Obtain regular ECGs to evaluate rate control
• Check electrolytes, particularly potassium and magnesium levels
• Monitor for amiodarone side effects (thyroid, liver, pulmonary)

Potential Pitfalls and Caveats

1. Avoid non-dihydropyridine calcium channel blockers

   • Diltiazem and verapamil can worsen bradycardia in patients with sick sinus syndrome 2
   • Patient already demonstrated bradycardia with Cardizem

2. Beta-blocker caution

   • Despite being common for rate control, beta-blockers like metoprolol can exacerbate bradycardia in patients with sick sinus syndrome 2, 3

3. Drug interactions

   • Amiodarone increases digoxin levels, requiring close monitoring and possible digoxin dose reduction 1
   • Multiple medications in this patient's regimen require careful evaluation for interactions

4. Pacemaker dependency

   • Ensure the pacemaker is functioning properly and programmed appropriately
   • Consider pacemaker interrogation to verify proper function

If pharmacological management fails to adequately control the atrial fibrillation despite these adjustments, AV node ablation with permanent pacemaker programming may be the most effective strategy to control symptoms and prevent further episodes of RVR and bradycardia 1.