Interference blocking and frequency selection
First Claim
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1. A method of determining a position of an instrument in a patient, comprising:
- moving the instrument into a volume of the patient;
determining a position of a position element only with a position sensing system, including;
providing a set of axis generation electrodes on an exterior surface of the patient establishing an axis and a conductive path therebetween;
selecting a first frequency for injection of a current into the patient between the axis generation electrodes;
injecting an axis current into the patient at the selected first frequency between the set of axis generation electrodes and generating a voltage gradient between the set of axis generation electrodes; and
evaluating an electrical property including sensing a voltage at the position element between the set of axis generation electrodes;
determining a position of the position element based at least on the sensed voltage along the voltage gradient between the set of axis generation electrodes;
measuring for an anomalous current frequency within the patient at a frequency other than the selected first frequency;
determining if the measured anomalous current frequency is an interfering frequency; and
changing the selected first frequency to a selected second frequency for injection of the axis current between the axis generation electrodes if it is determined that the measured anomalous current frequency is an interfering frequency.
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Abstract
A volume of a patient can be mapped with a system operable to identify a plurality of locations and save a plurality of locations of a mapping instrument. The mapping instrument can include one or more electrodes that can sense a voltage that can be correlated to a three dimensional location of the electrode at the time of the sensing or measurement. Therefore, a map of a volume can be determined based upon the sensing of the plurality of points without the use of other imaging devices. An implantable medical device can then be navigated relative to the mapping data.
281 Citations
27 Claims
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1. A method of determining a position of an instrument in a patient, comprising:
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moving the instrument into a volume of the patient; determining a position of a position element only with a position sensing system, including; providing a set of axis generation electrodes on an exterior surface of the patient establishing an axis and a conductive path therebetween; selecting a first frequency for injection of a current into the patient between the axis generation electrodes; injecting an axis current into the patient at the selected first frequency between the set of axis generation electrodes and generating a voltage gradient between the set of axis generation electrodes; and evaluating an electrical property including sensing a voltage at the position element between the set of axis generation electrodes; determining a position of the position element based at least on the sensed voltage along the voltage gradient between the set of axis generation electrodes; measuring for an anomalous current frequency within the patient at a frequency other than the selected first frequency; determining if the measured anomalous current frequency is an interfering frequency; and changing the selected first frequency to a selected second frequency for injection of the axis current between the axis generation electrodes if it is determined that the measured anomalous current frequency is an interfering frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 18)
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13. A method of determining a position of an instrument in a patient, comprising:
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moving the instrument with a position element into a volume of a heart of the patient; determining a position of the instrument using only a position sensing system, including; injecting current at a selected amperage into the patient at a selected first frequency and generating a voltage in the patient; and sensing the voltage with the position element and determining a position of the instrument based on the sensed voltage; determining if there is an anomalous current at an anomalous amperage within the patient at an anomalous frequency that is interfering with the selected first frequency; and changing the selected first frequency to a selected second frequency if it is determined that the anomalous current is interfering with the selected first frequency. - View Dependent Claims (14, 15, 16, 17)
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19. A system for determining a position of a device in a patient comprising:
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an instrument having a portion arranged to be inserted into a volume of a heart of the patient; a position element affixed to an exterior surface of the portion of the instrument arranged to be inserted into the volume, the position element arranged to sense an electrical property in the volume; a position sensing unit having a set of axis generation electrodes for injecting current at a selected first frequency into the patient, the axis generation electrodes adapted to be positioned on an outer surface of the patient and establish an axis via a conductive path through the patient, the injected current generating a voltage gradient in the patient between the set of electrodes; and a processor coupled to the position sensing unit, the position element and a display device, the processor operable to execute instructions to determine the position of the position element using only the position sensing unit and the position element, and to determine if an anomalous current at an anomalous frequency is present within the patient at an anomalous frequency other than the selected first frequency that is an interfering frequency. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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Specification