A 45-year-old man presents with palpitations, fatigue, and an irregular pulse. An ECG reveals atrial fibrillation with a rapid ventricular response (rate of 140 bpm). He has no history of structural heart disease, hypotension, or acute heart failure symptoms. Which of the following is the most appropriate initial management step?

✓ Correct Answer: Option B

For hemodynamically stable patients with new-onset atrial fibrillation and rapid ventricular response, rate control is the initial goal. Calcium channel blockers (like diltiazem) or beta-blockers are first-line agents. Cardioversion is for unstable patients. Amiodarone is typically for rhythm control or refractory cases. Adenosine is for SVT.