What is the best course of action for a patient with new onset atrial fibrillation (A-fib) with rapid ventricular response (RVR) after being treated for severe enterocolitis, dehydration, and early sepsis in the emergency department?

Management of New Onset Atrial Fibrillation with Rapid Ventricular Response After Enterocolitis

For a patient with new onset atrial fibrillation with rapid ventricular response following treatment for severe enterocolitis, dehydration, and early sepsis, a rate control strategy with beta blockers or calcium channel blockers is the recommended first-line approach. 1

Initial Assessment

• Evaluate hemodynamic stability (blood pressure, signs of hypoperfusion)
• Assess for ongoing sepsis or dehydration (which may have triggered the A-fib)
• Check electrolytes, particularly potassium and magnesium levels
• Consider thyroid function tests (hyperthyroidism can precipitate A-fib)
• Obtain an echocardiogram to assess cardiac function and rule out structural heart disease

Management Algorithm

Step 1: Hemodynamic Assessment

• If hemodynamically unstable (hypotension, altered mental status, ongoing ischemia):

  • Immediate electrical cardioversion 1

• If hemodynamically stable (as appears to be the case here):

  • Proceed with rate control strategy

Step 2: Rate Control Therapy

First-line agents:

• Beta blockers (preferred if no contraindications):
  • Metoprolol 5mg IV slowly over 5 minutes, may repeat up to 3 doses 1
  • Atenolol is also effective for rate control 1

OR

• Non-dihydropyridine calcium channel blockers:
  • Diltiazem 0.25 mg/kg IV over 2 minutes, followed by infusion at 5-15 mg/hour 1, 2
  • Verapamil is also effective for rate control 1

Special considerations for this patient:

• Given recent enterocolitis and sepsis, carefully monitor for hypotension with either agent
• If evidence of heart failure exists, beta blockers should be used with caution 1
• If the patient has COPD or pulmonary issues, calcium channel blockers are preferred over beta blockers 1

Second-line agents:

• Digoxin (if beta blockers and calcium channel blockers are contraindicated)
  • Note: Digoxin is only effective for rate control at rest 1
• Amiodarone can be considered if other agents fail or are contraindicated 1

Step 3: Anticoagulation Assessment

• Calculate CHA₂DS₂-VASc score to assess stroke risk
• If score ≥2 (which is likely in this patient with recent sepsis), initiate anticoagulation unless contraindicated 1
• Direct oral anticoagulants (DOACs) are preferred first-line agents 3
• If anticoagulation is initiated, it should be continued regardless of whether sinus rhythm is restored 1

Important Considerations and Pitfalls

• Post-sepsis A-fib: Recent evidence suggests that A-fib occurring after sepsis has higher recurrence rates than previously thought and may warrant long-term management 4

• Electrolyte management: Ensure potassium and magnesium are repleted to normal levels, as deficiencies can perpetuate arrhythmias

• Avoid certain medications: In patients with pre-excitation syndromes (WPW), avoid adenosine, digoxin, and calcium channel blockers as they can paradoxically increase ventricular rate 1

• Monitoring: Continuous cardiac monitoring is essential during initial management to assess response to therapy and detect any deterioration

• Long-term management: Consider whether this is a transient event related to acute illness or if the patient requires long-term rate control and anticoagulation

Given the patient's recent history of enterocolitis, dehydration, and early sepsis, this episode of A-fib with RVR is likely triggered by these acute conditions. However, the patient should be evaluated for underlying cardiac disease that may predispose to recurrent A-fib.