An implantable medical device lead includes an insulative lead body, an outer conductive coil extending through the lead body, and an inner conductive coil extending coaxially with the outer conductive coil. The outer conductive coil, which is coupled to a proximal electrode at a distal end of the outer conductive coil, has a first outer conductive coil diameter. The inner conductive coil is coupled to a distal electrode at a distal end of the inner conductive coil. The inner conductive coil includes a filar having a filar diameter and a coil pitch that is about one to one and a half times the filar diameter. The inner conductive coil transitions from a first inner conductive coil diameter to a larger second inner conductive coil diameter between the proximal electrode and the distal electrode.