Nonlinear conductance-volume relationship for murine conductance catheter measurement system.
The conductance catheter system is a tool to determine instantaneous left ventricular volume in vivo by converting measured conductance to volume. The currently adopted conductance-to-volume conversion equation was proposed by Baan, and the accuracy of this equation is limited by the assumption of a linear conductance-volume relationship. The electric field generated by a conductance catheter is nonuniform, which results in a nonlinear relationship between conductance and volume. This paper investigates this nonlinear relationship and proposes a new nonlinear conductance-to-volume conversion equation. The proposed nonlinear equation uses a single empirically determined calibration coefficient, derived from independently measured stroke volume. In vitro experiments and numerical model simulations were performed to verify and validate the proposed equation.
Wei
Chia-Ling
CL
Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA. chia-ling.wei@silabs.com
Valvano
Jonathan W
JW
Feldman
Marc D
MD
Pearce
John A
JA
D000818:Animals; D006328:Cardiac Catheterization / Q000379:methods*; D002307:Cardiography, Impedance / Q000379:methods*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004553:Electric Conductivity; D051379:Mice; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*