LEFT-VENTRICULAR STROKE VOLUME BY SINGLE AND DUAL EXCITATION OF CONDUCTANCE CATHETER IN DOGS

The conductance method employs a multielectrode catheter to measure in tracavitary electric conductance from which left ventricular volume is estimated. A dual-excitation method introduced by us uses a more homo geneous electric field and thereby should enable more accurate volume estimation. In six anesthetized open-chest dogs we compared stroke vol ume obtained from electromagnetic flow probes with the conventional si ngle-excitation method and with the new dual-excitation conductance me thod. Caval occlusion and left atrial hemorrhage were used to obtain a wide range of stroke volumes. The slope of the relation between strok e volume calculated from the flow probes and from the conductance cath eter increased significantly (P < 0.001) from 0.635 with single excita tion to 0.835 with dual excitation, but the interanimal variability wa s not reduced. The linearity of the relation was substantially improve d.