First-line management of chronic heart failure includes beta blockers and angiotensin converting enzyme (ACE) inhibitors, as these agents have been shown to have significant benefits on morbidity and mortality in large clinical trials. Therefore, a substantial number of patients with chronic heart failure are receiving chronic beta blocker therapy, most commonly metoprolol succinate and carvedilol. However, despite significant advancements in the treatment of chronic heart failure, the natural history of the disease remains progressive and many patients develop acute decompensations requiring hospitalization. In the setting of acute decompensated heart failure, the use of inotropic agents may be required for hemodynamic support. The two most widely used inotropes are dobutamine and milrinone. Dobutamine primarily acts as a beta-1 receptor agonist with some effects on beta-2 and alpha-1 receptors. Milrinone is a phosphodiesterase III inhibitor, thus inhibiting the breakdown of cyclic adenosine monophosphate. As such, milrinone works at a site that is distal to beta receptors and may be less influenced by chronic beta blocker therapy. As such, one may speculate that the presence of a beta blocker would influence the hemodynamic response to dobutamine, but to a much lesser extent to milrinone, if at all.