Landiolol in Postoperative Atrial Fibrillation

Landiolol perfusion over 120 minutes in incremental doses : 0.5, 1, 2, 5 and 10 µg/kg/min. Doses are modified every 20 minutes

Placebo perfusion is sodium chloride NaCl 0.9% over 120 minutes in incremental doses : 0.03, 0.06, 0.12, 0.3 and 0.6 mL/kg/h. Doses are modified every 20 minutes. Perfusion are similar in landiolol group to preserve blind.