A 54-year-old woman with new-onset atrial flutter (2:1 conduction, HR 150) is hemodynamically stable. What is the best initial rate control?AAdenosine continuous infusionBBeta-blocker or nondihydropyridine calcium channel blockerCIV amiodarone immediately for allDDigoxin as sole first-line in active patientESynchronized cardioversion immediately despite stabilityCheck my answer