A patient with an implantable cardioverter-defibrillator (ICD) experienced inappropriate shocks. X-rays revealed that the ventricular lead was fractured at a point, which seemed to be in a mechanical stress-free space in the heart. Multiple leads were entwined making a short flexible section sandwiched between the entwined area and the stiff coil susceptible to the stress from heart beats. The present case shows that indirect concentrated stress caused by restriction of lead flexibility can result in lead fracture. Upon implanting multiple endocardial leads, attention should be given to the relative position of each lead.