The Influence of Beta Blocker Therapy on the Hemodynamic Response to Inotrope Infusion in Patients With Acute Decompensated Heart Failure

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. Procedures: After obtaining informed consent, patients will be assigned to the appropriate sub-study group based on beta blocker use (Study A: patients on stable doses of metoprolol and Study B: patients on stable doses of carvedilol). All patients should receive dobutamine followed by milrinone as outlined in the dosing algorithm (see inotrope dosing algorithm attached, as part of the usual standard of practice). Baseline pulmonary artery catheter hemodynamic parameters will be collected prior to administration of inotrope trial of dobutamine followed by milrinone. Hemodynamic parameters will be recorded per the dosing algorithm following initiation and dose titration. Dose titration will be determined by the health care team based upon patient response or lack thereof and tolerability. Changes in hemodynamic parameters in response to dobutamine or milrinone will be compared within study groups. Additionally, data will continue to be collected on patients receiving not beta blocker therapy for comparative purpose.