Electrolytic phenomena and massive gas generation around pacemaker electrodes. Clinical presentation of an unusual pacing failure.

An unexpected clinical presentation of an unusual pacing failure has been observed in two patients who had had recent implantation of a pacemaker model whose electrodes were made of an nonnoble metal alloy. An intermittent current leakage from the output capacitor and possibly from the output transistor accounted for electrolytic corrosion at the anode, premature depletion of the battery, heart muscle damage and for massive gas generation around electrodes, leading to right ventricular perforation, pneumopericardium and subcutaneous thoracic emphysema. The occurrence of this syndrome shows that, if nonnoble metals are used for electrodes, more attention should be addressed to those conditions which add to polarization problems, as is current leakage from the output circuit components.