Cardiovascular Implantable Electronic Devices -> Leads & Electrodes: -> Technology D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-227 - Carbon Nanotube Fibers As Flexible Pacemaker Leads: Electrophysiologic Characterization (ID 152)


Background: Carbon nanotube fibers (CNTf) have been demonstrated to be durable, highly conductive substrates that can carry electrical signals in many biological applications. However, the data is lacking regarding their behavior in chronic non-rodent cardiovascular models. Large animal data will be critical to understanding the potential pacing applications of this new technology.
Objective: Assess the pacing behavior of CNT fibers in both acute and chronic large animal models.
Methods: In both acute and chronic porcine models, CNT fibers were sutured from the left atrium to the left ventricle(Fig 1. A). In the acute model, the fiber length and pacing locations on the ventricle were varied while attempting retrograde atrial capture. In the chronic model, a pacing grid was used to assess retrograde atrial capture. Hearts from the chronic animals were sent for histological analysis.
Results: Atrial capture was achieved by ventricular pacing in proximity of CNT fibers in only the acute models. Cathodic pacing with shorter fibers had lower capture thresholds. Atrial capture was not achieved in the chronic model, and histology (Fig 1. B-E) showed sites of foreign body inflammation with mild hemorrhage and, and intermixed scarce fine black filaments from the CNTf.
Conclusion: Here we have identified optimal pacing parameters and improvements needed before CNTf is ready for clinical application in the heart. Decreased signal dissipation is needed for low capture threshold. Further modifications of CNTf, such as a bioactive coating, will be required to prevent insulation-layer formation on the fiber over time in long-term applications.