Study enrollment too slow, 1 over 6 months

Adult patients who are diagnosed new onset atrial fibrillation with rapid ventricular response within 7 days after non-cardiac non-thoracic surgery are enrolled.

After randomization, they are allocated to rhythm control strategy group or rate control strategy group. In rhythm control strategy group, patients are given amiodarone primarily for the purpose of sinus conversion of cardiac rhythm. In rate control strategy group, patients are given diltiazem or esmolol for the purpose of rate control. the rate of sinus conversion within 48 hours after treatment are compared.

Inclusion Criteria:

• Older than 18 years
• Newly diagnosed atrial fibrillation or flutter
• Patients with atrial fibrillation or flutter that occurred within 7 days after non-cardiac non-thoracic surgery
• Atrial fibrillation or flutter with rapid ventricular response(HR ≥110/min)
• Patients without hemodynamic instability (MBP≥65mmHg with norepinephrine continuous infusion less than 5mcg/min or without vasopressor support)

Exclusion Criteria:

• Atrial fibrillation or flutter prolonged more than 48 hours without anticoagulation
• Patients who have decreased cardiac function or heart failure (EF <40%)
• Patients who have cardiac conduction disorder, QT prolongation(QTc ≥500ms)