Bipolar pacemaker leads: new materials, new technology

This commentary is in response to a review published earlier in this journal. It is intended to provide additional information and supplement the original paper. A short review of the failure mechanisms of polyurethane pacing lead materials is provided. Two specific degradation mechanisms, environmental stress cracking and metal ion oxidation, are discussed. Environmental stress cracking has been extensively studied and is a well understood failure mechanism. Methods for reducing the problem have been developed and tested in vivo. As a result, stress cracking failures can be virtually eliminated. Metal ion oxidation failures now dominate pacing lead recalls. Two new materials, polycarbonate urethanes and ethylenetetrafluoroethylene, have been introduced as insulators for pacing leads. These materials do not fail by stress cracking and preliminary test results are very positive.