A new approach to determine parallel conductance for left ventricular volume measurements

Objectives: To determine absolute ventricular volume with the conductance c atheter technique, the electrical conductance of tissues and fluids (parall el conductance) around the ventricle should be determined precisely. Method s: A new objective method to estimate parallel conductance based on analysi s of the dilution curve of hypertonic saline was investigated. The parallel conductances obtained with the new method (G(p)(a)) were compared to those obtained with the conventional method (G(p)(1)). The study was performed i n the left ventricle of 12 patients. Results: G(p)(a) was not significantly different from G(p)(1). For the G(p)(1) method the average percentage diff erence between duplicate values, both taken as absolute values, was 15.06% and for the G(p)(a) method it was 4.01%. Thus the reproducibility of the me thod is a factor four better than that of the method. This difference appea red to be significant. Conclusion: We conclude that a smaller number of inj ections will be required to obtain the same precision using our method. (C) 2000 Elsevier Science B.V. All rights reserved.