The investigators propose to conduct a randomized, placebo-controlled, double-blind, multicentre definitive trial of 1400 patients across 20 sites in Germany and Canada, which will include the pilot study patients. An industry partner (Biosyn) will provide the product and some additional support for the European sites. Patients will be randomized to receive either a daily perioperative high-dose selenium or placebo until postoperative day 10 (maximum) or upon earlier discharge from ICU. If the hypothesis is proven true, and this simple, inexpensive nutrient reduces complications and improves recovery of patients undergoing cardiac surgery, there is the potential to dramatically change clinical practice and improve health outcomes.