Frequent monomorphic premature ventricular complexes (PVCs) may cause a cardiomyopathy (CMP) that is reversible by suppression of the ectopic focus. This study investigates whether PVC suppression therapy can improve cardiac function and clinical condition of patients with idiopathic or ischemic CMP and frequent monomorphic PVCs. For this purpose, patients will be randomized to either one of two treatment strategies: 1) conventional heart failure therapy plus PVC suppression therapy, consisting of RFCA as primary treatment and Amiodarone as secondary treatment in case of unsuccessful RFCA, or 2) conventional heart failure therapy without PVC suppression therapy.