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Method and apparatus to correct for electric field non-uniformity in conductance catheter volumetry

  • US 5,971,933 A
  • Filed: 08/27/1997
  • Issued: 10/26/1999
  • Est. Priority Date: 09/17/1996
  • Status: Expired due to Fees
First Claim
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1. A method of determining cardiac volume by means of a catheter adapted to be positioned in a blood filled chamber of a human heartthe catheter comprising an elongated body having a distal end and proximal end, a plurality of spaced electrodes arrayed on the outer surface of the catheter and being spaced apart a predetermined distance from each other to define a proximal electrode and a distal electrode and a plurality of electrodes disposed therebetween, pairs of adjacent electrodes between the distal and proximal electrodes defining volume segments within the chamber,the method comprising the steps of positioning the catheter in a blood filled chamber of a human heart, the catheter assuming an arcuate configuration so that the segments of the catheter between adjacent electrodes are curved,providing a constant alternating electrical excitation to the distal and proximal electrodes,measuring an electrical parameter between pairs of adjacent electrodes located between the distal and proximal electrodes while the distal and proximal electrodes are energized with the electrical excitation,determining the uncorrected volume of each volume segment from the measured electrical parameters,determining a correction factor CF for each volume segment from the accurate curvature of the segment, andapplying the correction factor CF to the uncorrected volume of each volume segment to provide a corrected volume for each segment.

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