Postoperative atrial fibrillation (POAF) occurs in nearly 30% of patients undergoing conventional cardiac surgery. 

Landiolol, a short-acting i.v. beta blocker, could reduce both the incidence of POAF and postoperative microcirculatory abnormalities. 

However, the effects of landiolol on microcirculation remain poorly documented. The aim of this prospective randomised, controlled, double-blind study conducted in patients undergoing cardiac surgery was to assess the microcirculatory effects of landiolol given at a moderate dose to prevent POAF. We tested the hypothesis that landiolol could limit cardiopulmonary-bypass-induced microcirculatory abnormalities.