Developing a successful cardiac device requires detailed knowledge of cardiac mechanical properties. For example, tissue failure characteristics and compliance feed into design criteria for many pacemaker leads (Zhao et al., 2011).
In the right atrium, tensile forces are exerted on the right atrial appendage in multiple clinical procedures. In a traditional lead implant, mechanical manipulations with a stylet aid a clinician in assessing lead fixation, with a seldom used “tug” test providing additional input. Atrial lead dislodgement remains one of the top complications for bradycardia pacing leads (Chahuan et al., 1994), in part because there is no standard mechanical assessment at implant to verify fixation. Thus, a deeper understanding of forces exerted on the atrium during implant, is fundamental to understanding the problem. Further characterization of the biomechanics relevant to atrial device implants will provide valuable design input for fixation tests and help drive research toward new atrial fixation mechanisms.
This study aims to better define the relationships between right atrial stiffness and the chamber pressures within the right atrium, so to characterize the link between tensile displacement within the right atrium, and the force exerted on an implanted device in a functional heart. These experiments quantitatively define the fixation force of a fixed cardiac device with a given pulled displacement; i.e. displacing the device a given distance will effectively ensure the experimentally derived fixation force.