What is a common postoperative arrhythmia after CABG, and how is it typically managed?

• A. Atrial fibrillation; managed with rate/rhythm control, beta-blockers, amiodarone, and other rhythm-control strategies as appropriate.
• B. Ventricular fibrillation; managed with vasopressors only.
• C. Sinus bradycardia; no treatment.
• D. Third-degree AV block; immediately explanted.

Answer: (A)

The main concept here is recognizing the most common rhythm problem after CABG and how it’s typically handled. Atrial fibrillation is the usual culprit, arising in the immediate postoperative period—often within the first 24 to 48 hours—likely from atrial irritation from surgery, inflammation, and shifts in autonomic tone and electrolytes.

Management focuses on controlling the heart rate and, if needed, restoring or maintaining a normal rhythm. Rate control is commonly started with beta-blockers to slow the ventricular response and lessen myocardial demand. If rhythm control is pursued, amiodarone is a favored option after CABG because it is effective at converting or maintaining sinus rhythm with a favorable safety profile in the postoperative setting. Other rhythm-control strategies can be used as appropriate, including electrical or chemical cardioversion if the arrhythmia persists or causes symptoms. In addition, decisions about anticoagulation are guided by how long AF lasts and the patient’s stroke risk once the patient is stabilized.

Why the other scenarios aren’t the typical post-CABG pattern: ventricular fibrillation is a life-threatening event that triggers immediate resuscitation rather than a routine postoperative management plan. Sinus bradycardia can occur but is not treated with a blanket “no treatment” approach; it may require observation, atropine, or pacing if symptomatic. A third-degree AV block is a pacing indication, not an “immediate explant” situation, and requires pacing support.