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Long‐Term Performance of Polyurethane Pacing Leads: Mechanisms of Design‐Related Failures
Author(s) -
PHILLIPS RICHARD,
FREY MICHAEL,
MARTIN RICHARD O.
Publication year - 1986
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1986.tb06688.x
Subject(s) - polyurethane , electromagnetic coil , stress (linguistics) , polymer , composite material , lead (geology) , environmental stress cracking , cracking , materials science , intrusion , stress corrosion cracking , corrosion , electrical engineering , linguistics , philosophy , geochemistry , geomorphology , geology , engineering
Environmental stress cracking has been identified as a crack propagating mechanism in polyurethane‐insulated, heart pacemaker leads, which is directly related to specific lead design parameters. Lead designs imposing excessive stress on the polyurethane insulation through an interference fit between the coil and polymer have demonstrated insulation failures. Conversely, low‐stress designs have shown virtually no insulation problems. The higher‐stress designs have used organic solvents to facilitate coil placement during manufacturing. which may result in lowering the polymer's ability to resist the higher stress. In addition, a specific silver‐containing coil wire composition has been found to galvanically corrode upon body fluid intrusion info the lead, ionizing the silver. These ions interact with the polyurethane polymer resulting in the loss of polymer strength. All polyurethane lead failures to date have been specific to high stress and/or chemical interaction. Leads using low‐stress designs and nonreactive coil wire compositions continue to demonstrate a positive clinical experience.