The invention describes fluid-based lead systems. The fluid-based leads may be used for sensing from, and stimulating of, human tissue. The fluid-based leads can be used to transfer signals between two locations. The fluid-based leads offer advantages when communicating signals along their length since the leads may be safely used in magnetic environments and offer increased elastic characteristics which are less prone to breakage. The leads can be used externally or with implantable devices, such as those used to monitor, and deliver therapy during the treatment of medical disorders such as cardiac and neurological disorders.