BACKGROUND OF THE INVENTION The electrical activity generated in certain organs in
the human body is intimately related to their function. Abnor malities in cardiac and brain
electrical conduction processes are principal causes of morbidity and mortality in the
developed World. Appropriate treatment of disorders arising from such abnormalities
frequently requires a determination of their location. Such localiZation of the site of origin of
an abnormal electrical excitation is typically achieved by pains taking mapping of the …

This invention involves method and apparatus for guiding ablative therapy of abnormal
biological electrical excitation. In particular, it is designed for treatment of cardiac
arrhythmias. In the method of this invention electrical signals are acquired from passive
electrodes, and an inverse dipole method is used to identify the site of origin of an arrhytmia.
The location of the tip of the ablation catheter is similarly localized from signals acquired
from the passive electrodes while electrical energy is delivered to the tip of the catheter. The …