The hemodynamic effects of dobutamine and isoproterenol infusions were studied in five Holstein calves 1 day before and 2 days after the implantation of a Jarvik-7 total artificial heart (TAH). Cardiac output was decreased, and systemic vascular resistance (SVR) and pulmonary vascular resistance were increased after TAH implantation. Administration of dobutamine before TAH implantation caused an increase in heart rate, and discontinuation of dobutamine decreased cardiac output. Administration of dobutamine after TAH implantation caused decreases in mean arterial pressure and SVR. Isoproterenol increased heart rate and cardiac output and decreased SVR before TAH implantation. Isoproterenol produced no significant hemodynamic effects after TAH implantation. These results describe the hemodynamic effects that could be expected from normal clinical infusions of these drugs in the patient who is supported by the TAH as a bridge to heart transplantation; these results are of additional interest in that they describe the peripheral effects of the two agents independent of cardiac effects.