Scientific and medical system circuitry for diagnosis of implantable cardioverter defibrillator (ICD) lead conductor anomalies, in particular conductor migration and externalization within an ICD implantable cardiac lead. The system determines an “imaginary” component of the high frequency transmission line impedance having certain spectral changes that correspond to radially outward movements or local externalization of a conductor within a lead body allowing for the detection of conductor migration and small insulation failures.
