A surrogate implantable medical device includes a thermally conductive and electrically conductive housing. A header connector block includes a header block body, where the header block body is attached to the housing. At least one connector cavity is located within the header block body and configured to be attachable to an implantable lead. At least one conductive leadwire is disposed at least partially within the header block body having a first end and a second end. The at least one conductive leadwires first end is electrically connected to the at least one connector cavity and the at least one conductive leadwires second end is electrically connected to the housing. The housing does not contain active electronics.