An implantable medical electrical lead for electrical stimulation of body tissue that includes at least one modifiable portion that exhibits a permanent configuration and a temporary configuration, wherein the temporary configuration exists only when the surrounding magnetic field is increased, wherein the permanent configuration of the modifiable portion exhibits a greater resistance to movement of the lead within the body tissue than does the temporary configuration; and at least one electrode configured to provide electrical stimulation of body tissue, wherein the lead has a proximal end and a distal end. Systems, and methods of implanting the leads are also included in the invention.