During the treatment of septic shock, a 28-year- old male remains hypotensive despite adequate volume replacement; PA occlusion pressure is 18 mm Hg. When dopamine is started, ventricular tachycardia develops and this is unresponsive to lidocaine. The V-tach converts back to sinus rhythm once the dopamine is stopped. At this point, which of the following treatments are most appropriate for this hypotensive patient?