Abstract: Systems and methods for determining a contact angle of a catheter relative to tissue are provided. In one embodiment, a system includes a catheter with three or more electrodes, and a processor circuit in communication with the catheter. The processor circuit controls the three or more electrodes to emit a plurality of electrical voltages and to measure the plurality of electrical voltages. Based on the measured electrical voltages, the processor circuit calculates a first interelectrode impedance and a second interelectrode impedance. The processor circuit calculates, for each of a plurality of hypothetical i.e. model angles, a first hypothetical i.e. model contact force and a second hypothetical i.e. model contact force based on the first and second interelectrode impedances. The processor circuit determines and outputs the contact angle of the catheter based on a comparison of the first and second model contact forces calculated for each of the plurality of model angles.

Abstract: A method of computing a dielectric map is disclosed comprising exciting at least one pair of electrodes according to an excitation scheme, the at least one pair of electrodes comprising at least one pair of in-body electrodes (also referred herein below intra-body electrode) located inside of the examined living body, measuring and recording voltages developing on the in-body electrodes during the excitation according to the excitation scheme, solving an inverse problem to derive a 3D dielectric map from the recorded voltages and optionally providing a 3D image of the body tissues based on the 3D dielectric map. Methods are also disclosed that combine intrabody electrodes and surface electrodes secured to the body or use only surface electrodes. Embodiments encompass the use of constraints in deriving the 3D dielectric map and combining measurements made at different locations inside the body with moving intrabody electrodes.

Abstract: Systems and methods for determining a contact angle of a catheter relative to tissue are provided. In one embodiment, a system includes a catheter with three or more electrodes, and a processor circuit in communication with the catheter. The processor circuit controls the three or more electrodes to emit a plurality of electrical voltages and to measure the plurality of electrical voltages. Based on the measured electrical voltages, the processor circuit calculates a first interelectrode impedance and a second interelectrode impedance. The processor circuit calculates, for each of a plurality of hypothetical i.e. model angles, a first hypothetical i.e. model contact force and a second hypothetical i.e. model contact force based on the first and second interelectrode impedances. The processor circuit determines and outputs the contact angle of the catheter based on a comparison of the first and second model contact forces calculated for each of the plurality of model angles.

Abstract: A method of evaluating electrical impedance across a gap between a first catheter electrode and a second catheter electrode, both carried on a same catheter is provided. The method includes: receiving measurements of electrical voltages; and evaluating the electrical impedance across the gap based on the measurements of the electrical voltages. In some embodiments, the electrical voltages include: a first electrical voltage, which is a voltage measured between a reference electrode and the first catheter electrode measured under a first alternating electrical current having a first frequency and flowing through a conductor from an electrical source to the first catheter electrode, and a second electrical voltage, which is a voltage measured between the reference electrode and the second catheter electrode under the first alternating electrical current.