Accuracy of the conductance catheter for measurement of ventricular volumes seen clinically: effects of electric field homogeneity and parallel conductance

The conductance-volume method is an important clinical tool which allows the assessment of left ventricular function in vivo. However, the accuracy of this method is limited by the homogeneity of electric field the conductance catheter produces and the parallel conductance of surrounding structures. This paper examines these sources of error in volumes seen clinically, The characteristics of electric field within a chamber were examined using computer simulation. Nonconductive and conductive models were constructed and experimental measurements obtained using both single-field (SF) and dual-field (DF) excitation. Results from computer simulations and in vitro measurements were compared to validate the proposed theoretical model of conductance-volume method. The effects of field homogeneity and significance of parallel conductance in volume measurement were then determined. The results of this study show that DF provide a more accurate measure of intraventricular volume than SF, especially at larger volumes. However, both significantly underestimate true volume at larger volumes. In addition, the parallel conductance due to the chamber wall is significant at small volumes, but diminishes at larger volumes. Furthermore, the effect of parallel conductance beyond the chamber wall may be negligible. This study demonstrates the limitations in applying current conductance technology to patients with dilated hearts.

[1]  S A Glantz,et al.  Left ventricular volume measurement by conductance catheter in intact dogs. Parallel conductance volume depends on left ventricular size. , 1989, Circulation.

[2]  Jan Baan,et al.  Computation of the Input Impedances of a Catheter for Cardiac Volumetry , 1984, IEEE Transactions on Biomedical Engineering.

[3]  M. Feldman,et al.  Intracoronary angiotensin-converting enzyme inhibition improves diastolic function in patients with hypertensive left ventricular hypertrophy. , 1994, Circulation.

[4]  A R Jayaweera,et al.  Why do patients with congestive heart failure tolerate the initiation of beta-blocker therapy? , 1993, Circulation.

[5]  A A Shoukas,et al.  Does volume catheter parallel conductance vary during a cardiac cycle? , 1990, The American journal of physiology.

[6]  P. Steendijk,et al.  Left ventricular stroke volume by single and dual excitation of conductance catheter in dogs. , 1993, The American journal of physiology.

[7]  M. Valentinuzzi,et al.  Volume profiles obtained by a conductimetric method. , 1993, Journal of Biomedical Engineering.

[8]  S. Kun,et al.  Conductance volumetric model of an eccentrically positioned catheter within a three-compartment ellipsoidal ventricle , 1993, IEEE Transactions on Biomedical Engineering.

[9]  Editor-H.P. Westman Reference Data for Radio Engineers , 1967 .

[10]  B Buis,et al.  Continuous measurement of left ventricular volume in animals and humans by conductance catheter. , 1984, Circulation.

[11]  D. Kass,et al.  Acute cardiovascular effects of OPC-18790 in patients with congestive heart failure. Time- and dose-dependence analysis based on pressure-volume relations. , 1996, Circulation.

[12]  W L Maughan,et al.  Use of a conductance (volume) catheter and transient inferior vena caval occlusion for rapid determination of pressure-volume relationships in man. , 1988, Catheterization and cardiovascular diagnosis.

[13]  H. T. Kohlhaas,et al.  Reference data for radio engineers , 1943 .