Real time conductance catheter system based on FPGA

This paper presents a digital conductance catheter system based on FPGA (Field Programmable Gate Arrays) to measure real time ventricular volumes for experimental use. The system performance is realized in three stages: a) conductance measurements using a well-known set of resistance connected to each catheter section; b) volumes measurements in glass containers of well-known geometry that contain a solution with a resistivity similar to the blood, and c) comparison between the previous analog conductance catheter system and this novel FPGA based system. Catheter section volumes are measured in a range of 3ml to 20ml; the equivalent conductances are between 0.022S to 150S. If five sections can be added, the range of the total ventricular volume is between 3ml to 100ml. The maximum percentage error in each sector conductance was 5% for all values. Finally, relationship between true (analog system) and the measured conductances (digital FPGA based system) have a correlation coefficient of 0.983.