FPGA-based phase and module impedance meter

• Published in: Journal of physics. Conference series Vol. 477; no. 1; pp. 12006 - 10
• Main Authors: López, M A Gómez, Migliorino, F A, Goy, C B, Acuña, J B, Herrera, M C
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2013
• Subjects: Appropriate technology; Blood volume; Catheters; Conductance; Diastole; Estimates; Impedance; Meters; Modules; Muscles; Nonlinearity; Physics; Systole; Volume measurement
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/477/1/012006

A conductance catheter system measures the left ventricle volume by measuring the blood conductance in the cavity. It is known that there are some limitations and errors related to these assumptions. New trends claim that a nonlinear conductance-volume relationship is observed and volume measurement not only has a resistive behavior but also has a capacitive component. It is exclusively due to the myocardial muscle; even further, myocardial impedance varies in both phase and magnitude between end systole and end diastole decreasing the accuracy of volume measurement. The incorporation of an appropriate technology catheter system based on FPGA is proposed allowing measure impedances instead of conductances. Thus, the system can measure impedance module and phase in order to accurately estimate the left ventricle blood volume. The system is digitally designed and evaluated with known pattern impedances with electrical characteristics similar to those presented in the left ventricle (module range of 6.8Ω to 47Ω and phases from 2° to 90°).