To determine whether the extent of myocardial fibrosis by late-gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR), and echocardiographic ventricular dyssynchrony are independently associated with response to medical therapy in patients with newly diagnosed idiopathic dilated cardiomyopathy (DCM). Myocardial fibrosis and ventricular dyssynchrony are frequent findings in DCM. Previous studies focused on patients with established cardiomyopathy; however, the degree of myocardial fibrosis and ventricular dyssynchrony at presentation and their role in perpetuating left ventricular (LV) dysfunction in DCM remains unclear. Those studies of individuals with long-standing DCM did not characterize patients early in the disease course, and may not have included those with significant improvement in LV function. Thus factors contributing to LV recovery are uncertain.