An equivalent generator representation of measured intracavitary potentials

The objective of this study was to determine the accuracy of an equivalent generator model in representing measured intracavitary potentials. A cylindrical probe (45 × 10 mm) was placed in the left ventricular cavity of six canines. Potentials were recorded from 40 unipolar electrodes evenly dispersed on the probe´s surface. For a given intracavitary potential distribution, an iterative procedure was developed to calculate the optimum location of the equivalent source generator based on a moving dipole-moving quadrupole model. The results indicated that dipole terms alone account for approximately 76% and 59% of the measured intracavitary potentials at the midpoint of the QRS complex and at the midpoint ST-T segment, respectively. With the addition of the quadrupole terms, the accuracy increases to 97% and 88%, respectively. Despite the fact that an equivalent generator model is not a physiologic representation but rather a mathematical representation of electrical sources, the results indicate that a high degree of accuracy is obtainable. Thus, this method of representing intracavitary potential distributions could provide important diagnostic information to physicians and scientists.