Purpose: To compare the hemodynamic effects of dobutamine and milrinone in hospitalized patients who are receiving Beta Blocker Participants: Patients who are admitted to the General Cardiology and Heart Failure Services at the University of North Carolina Hospitals with acute decompensated heart failure, who have maintained steady state concentrations of beta blocker therapy (carvedilol or metoprolol), and who are deemed by the health care team to require pulmonary artery catheter placement and inotropic therapy with dobutamine or milrinone by continuous infusion. Patients that are not currently receiving beta blocker therapy will be enrolled for comparative purposes; however, any patient not at steady state (on or off beta blocker therapy) will not be enrolled.