Surge protection for equipment that is implanted in the human body, such as pacemakers, present a special case as far as surge protection design is concerned. This is because it is highly likely that the input to the pacemaker will see the effects of a potentially damaging surge that is applied deliberately. These might occur when the patient is subjected to electric shock during emergency medical treatment such as defibrillation, or during an operation when cauterisation is used to stop bleeding. The growing use of body-implanted electronic devices for the treatment of: Parkinson's disease, chronic pain, for muscle control, incontinence, diabetes and neuro-stimulation has raised the importance of this special type of surge protection.