Intracavitary mapping: an improved method for locating the site of origin of ectopic ventricular beats by means of a mathematical model

The authors extend their previous technique of localizing an ectopic focus by utilizing the entire potential distribution on the probe to compute the spatial coordinates of the site of origin of ectopic ventricular beats as solution of an inverse problem in terms of sources. On the basis of previous investigations, they represent the unknown source, at QRS onset, by two equal-strength opposing dipoles located at the ends of a short segment whose midpoint was at the ectopic site. The two dipoles simulate the anisotropic properties of both cardiac sources and myocardial tissue in an infinite homogeneous conducting medium. Preliminary results indicate that the model gives a better estimate of the location of an ectopic focus than can be obtained by taking only into account the position of the potential minimum on the probe surface.<>