SYSTEM AND METHOD FOR A CATHETER IMPEDANCE SEEKING DEVICE
First Claim
1. An apparatus for making and maintaining continuous tissue contact between a tool tip and moving tissue in a patient, comprising:
- a controllable magnetic field source that produces a magnetic field;
a tool having a distal end responsive to said magnetic field;
one or more sensors configured to sense a current vector position of said distal end by measuring one or more impedances;
a controller for controlling said magnetic field source to control a movement of said distal end according to a feedback calculation wherein said system controller is configured to compute a position error comprising a difference between a desired vector position of said distal end and said current vector position of said distal end; and
an operator control that provides tactile feedback to an operator when said position error exceeds a predetermined amount, wherein said tactile feedback is computed by said controller at least in part according to said vector position error, wherein a correction input to said desired vector position is computed based on a position of a heart relative to a frame of reference, such that said system controller compensates for a dynamic position of a wall of a heart chamber such that said distal end maintains contact with said wall of said heart chamber at least in part by measuring at least one impedance between said distal end and said wall.
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Accused Products
Abstract
A tissue-contact seeking method and apparatus is described that enhances catheter position detection and control systems in making and maintaining continuous tissue contact in a highly dynamic frame, such as under the rigors of cardiac motion. Tissue-seeking logical routines use a tissue contact sensing system to advance a catheter to relatively continuous tissue contact, or detect obstacles, in cooperation with the catheter position detection and control systems. Additional logical routines are capable of optimizing the contact direction of the catheter tip by controlling the rotation angle and chamber position of the introducer.
121 Citations
24 Claims
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1. An apparatus for making and maintaining continuous tissue contact between a tool tip and moving tissue in a patient, comprising:
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a controllable magnetic field source that produces a magnetic field; a tool having a distal end responsive to said magnetic field; one or more sensors configured to sense a current vector position of said distal end by measuring one or more impedances; a controller for controlling said magnetic field source to control a movement of said distal end according to a feedback calculation wherein said system controller is configured to compute a position error comprising a difference between a desired vector position of said distal end and said current vector position of said distal end; and an operator control that provides tactile feedback to an operator when said position error exceeds a predetermined amount, wherein said tactile feedback is computed by said controller at least in part according to said vector position error, wherein a correction input to said desired vector position is computed based on a position of a heart relative to a frame of reference, such that said system controller compensates for a dynamic position of a wall of a heart chamber such that said distal end maintains contact with said wall of said heart chamber at least in part by measuring at least one impedance between said distal end and said wall. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for positioning a surgical tool and maintaining relatively continuous contact between a distal end of said tool and a desired tissue location, comprising:
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controlling a position and orientation of a distal end of a surgical tool by adjusting currents in a plurality of electromagnets; measuring a plurality of impedance values between said distal end and a plurality of tissue locations; constructing an impedance map at least in part form said plurality of impedance values; determining a first impedance value corresponding to an impedance measured when said distal end touches said desired tissue location; and using a feedback controller to control said currents to maintain contact between said distal end and said desired tissue such that said distal end is oriented relatively normal to said desired tissue location in the presence of motion of said desired tissue location, wherein feedback information to said feedback controller comprises periodic impedance measurements between said distal end and said desired tissue location. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification