Decreased beta-adrenergic responsiveness is a characteristic feature of DCM that is attributable in part to decreased expression of the beta 1-receptor in chronic heart failure, as well as dysregulation of down-stream signaling pathways. Improvement in beta-adrenergic responsiveness is a useful surrogate marker for long-term improvement in cardiac structure, function, and decreased cardiac events. Traditionally, invasive hemodynamic monitoring using pressure and pressure/volume catheters has been the method of choice to quantify the inotropic response in heart failure. However, newly developed magnetic resonance imaging (MRI) techniques now allow precise assessment of the inotropic response non-invasively. Studies have shown that tagged CMR is a reproducible, noninvasive method to quantify the inotropic response to the beta 1 agonist dobutamine in individuals with structurally normal hearts. Specifically, radial strain (E1) and circumferential strain (E2) are measured at increasing doses of dobutamine using tagged CMR. Changes in these strain parameters, now referred to as delta E1 and delta E2, are precise measurements of the beta-inotropic response.