A new test for pacemaker leads: Capacitance measurement

A device has been developed which permits in man the measurement of the capacitance of a chronically implanted pacemaker lead at the moment of battery replacement. A large increase in capacitance suggests important body fluid penetration into the lead. This can be due to an insulation defect (caused by a suture or a guide wire during implantation) or to a degeneration of the insulation material or to the lead-design. This fluid penetration should be avoided since it can be responsible for some electro-chemical reactions. Calculated values for the capacitance of a system consisting of an inner and an outer conductor, with two media in between, agree rather well with measured values. It is suggested that the measurement of the capacitance of a pacemaker lead is an additional tool for the evaluation of chronically implanted pacemaker leads. This method can also be of interest for the quality control of pacemaker leads.