Patients presenting with idiopathic dilated cardiomyopathy and left ventricle dysfunction (LVEF \<40%), naive of anti-remodeling cardiac medical therapy, will undergo invasive coronary microvascular assessment based on thermodilution. The primary endpoint, namely the left ventricle reverse remodeling, will be assessed after 12 months of optimal medical therapy based on transthoracic echocardiography. The primary endpoint will be evaluated by an independent central core lab. Patients enrolled in the study will be followed for a period of 5 years to monitor their clinical status. During the study period participants may undergo multimodality diagnostic tests including ECG telemetry monitoring, cardiopulmonary exercise testing, cardiovascular cardiac magnetic resonance.