Temporal and spatial summation of endocardial inverse solutions using a multielectrode probe

Localizing the sites of origin and identifying the mechanisms of arrhythmias are paramount to selecting appropriate pharmacological therapies or advancing nonpharmacological approaches for their management. The goal of the study was to develop and validate mathematical methods to reconstruct endocardial potentials (electrograms) and activation sequences from potential data measured with a noncontact multielectrode probe. A custom-made cylindrical probe was used to measure cavitary potentials in the canine intact left ventricle. The probe-cavity geometric model was determined using epicardial echocardiography. The boundary element method, combined with Tikhonov regularization, was used to compute the potentials at the endocardial surface. Endocardial electrograms were computed during paced rhythms and were in excellent agreement with directly-measured endocardial electrograms.