The Reproducibility of a Proposed Standard Fatigue Test for Cardiac Device Leads

摘要

The Transvenous Cardiac Leads Working Group of the Cardiac Rhythm Management Devices Committee of the Association for the Advancement of Medical Instrumentation is developing a fatigue performance standard for cardiac device leads. The proposed standard would calculate a figure-of-merit (FOM) that is based on a life prediction using a Bayesian framework. The framework uses distributions for bending fatigue strength, patient age, patient activity level, and in vivo bending. The benchtop fatigue testing portion of the standard is based on the unsupported bending of the lead at multiple alternating curvature levels to generate fatigue fracture data in low-cycle and high-cycle regimes. To estimate the interlaboratory reproducibility of the benchtop testing methodology, a lead mock-up was constructed from a bifilar MP35N coil in a thin-walled polyurethane tube. Four laboratories each tested 48 specimens and produced fatigue life curves based on the results. To compare the data, the FOM that is proposed for the standard was calculated using initial in vivo curvature data of a well-performing lead. The reproducibility standard deviation of the FOM across the four laboratories was 0.17 % of the grand mean.