title: Characterization of chronically implanted ventricular endocardial pacing leads.
abstract: The expected implant lifetime of pacemaker generators has been extended with the introduction of lithium power sources. Consequently, the pacing lead may become the component that determines the total implant lifetime of the pacemaker. This fact emphasizes the necessity for accurate assessment of the integrity of a chronically implanted lead. In this study, chronic threshold and impedance data from 61 patients having the same type of ventricular endocardial lead for up to 10 years were retrospectively analyzed. The mean acute current threshold was 0.81 +/- 0.33 mA. The chronic current threshold had a range of between 1 and 5 mA, which was approximately two to five times greater than the acute implant value. Chronic voltage threshold and impedance were 0.7 to 4 V and 335 to 775 omega, respectively. The findings of this study provide general guidelines for chronic lead parameters and illustrate some of the difficulties encountered in gathering and interpreting long-term lead data.
mesh_terms: D004553:Electric Conductivity; D004567:Electrodes, Implanted; D006801:Humans; D010138:Pacemaker, Artificial; D012189:Retrospective Studies; D013997:Time Factors