The purpose of this study protocol is to evaluate the blood concentrations of levosimendan when administered at different doses clinically employed during cardiopulmonary bypass or cardiac manipulation during off pump surgery in patients who require the drug for inotropic support (improved heart function) and the associated hemodynamic variables (vital signs). Levosimendan is one of the first agents in a new class of drugs used to treat heart failure and works via a unique mechanism called calcium sensitization, that makes the heart beat more efficiently. Levosimendan also has unique effects on the blood vessels, as well as causing relaxation, an important therapeutic approach of heart failure therapy.