The Fundamental Investigation Of The Three-dimensional Positioning And Navigation And The Reconstitution Of Endocardium's Model With Low-frequency Current Field

Objective: To approach the feasibility of the three-dimensional positioning and navigation with regular catheter electrodes in intracavitary with a low-frequency electrical field.Methods: Loading a spatial orthonormal low frequency alternating current field onto the surface of an experimental animal with three standard skin electrodes to creat low-frequency transthoracic orthonormal electrical fields to cover the area of the heart. Then regular catheter electrodes are used as sensors for a low-frequency transthoracic electrical field. We investigated localization accuracy within the right atrium. The datas which were recorded via standard catheter electrodes can be used to determine the electrodes position on the PC online. We got 7 tipical points in the right atrium and investigated localization accuracy by comparing measured and true electrode position of a decapolar catheter with X rays. At the same time, we investigated the distances of the necrosis points with Radio Frequency Catheter Ablation(RFCA). At last we reconstituted the endocardium's model by use of point- point type.Results: The low-frequency electrical field is of safety for the animals and Electrogram recordings were unaffected by the applied electrical field. Localization data from 7 catheter positions, widely distributed within the right atrium, were analyzed. localizations of 7 catheter positions were reproducible within 1.7±0.7mm in X direction,1.6±0.7mm inY direction,1.3±0.5mm in Z direction. The 5 necrosis points with RFCA mixed each other. The diameters of the necrosis focuses were 7 mm.Conclusions: (1) The method of a low-frequency transthoracic orthonormal electrical field, which is applied via standard skin electrodes is feasible. (2) The external electrical field is of safety for the experimental animals. (3) Electrogram recordings were unaffected by the applied electrical field. the technique can be applied to regular catheters and complex catheter designs such as multielectrode catheters, irrigated electrode catheters, and basket catheters. (4) This new technique enables accurate and reproducible real-time localization of electrode positions. (5) Although the reconstitution of endocardium's model by use of point- point type is of some deformation, the accuracy can meet the demand of the valid ablation of the target when RFCA.