In a patient with atrial fibrillation with rapid ventricular response who is unstable, what is the recommended intervention?

• A. Rate control with IV diltiazem
• B. Immediate synchronized cardioversion
• C. Observation
• D. Anticoagulation only

Answer: (B)

When atrial fibrillation with rapid ventricular response is causing instability, the priority is to rapidly restore effective cardiac output. Immediate synchronized cardioversion is used to convert the rhythm back to normal sinus rhythm and quickly stabilize perfusion. Rate-control medications like diltiazem are useful in stable AF with RVR, but in unstable patients they won’t quickly correct poor hemodynamics and can worsen hypotension. Observation offers no remedy for the hemodynamic collapse, and anticoagulation alone does not address the urgent need to restore rhythm. Synchronized cardioversion delivers a shock timed with the heart’s electrical activity to restore coordinated rhythm safely, and is the fastest way to reverse the instability in this scenario.