# US 12,178,503 B1 · Tissue ablation catheter with passive conductive elements to shape electric fields > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,178,503 B1 - Document ID: US12178503B1 - Status: Granted - Kind: B1 - Application number: 18/824,027 - Filed: 2024-09-04 - Published: 2024-12-26 - Granted: 2024-12-31 - Earliest claimed: 2022-12-09 - Assignees: Field Medical, Inc. - Applicants: Field Medical, Inc. - Inventors: Steven Mickelsen - Web page: https://patentgrep.com/patent/US12178503B1 ## CPC - A61B 18/1492: {having a flexible, catheter-like structure, e.g. for heart ablation (A61B18/1477 takes precedence)} - A61B 2018/00077: {high, i.e. electrically conducting} - A61B 2018/00083: {low, i.e. electrically insulating} - A61B 2018/00577: {Ablation} - A61B 2018/00613: {Irreversible electroporation} - A61B 2018/00767: {Voltage} - A61B 2018/00875: {Resistance or impedance} - A61B 2218/002: Irrigation - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A catheter for tissue ablation with one or more inner electrodes inside the lumen, one or more outer electrodes attached to the outer surface, and one or more passive conductive elements that are not connected to the power supply but that passively shape the electrical field. The electrodes may be offset from the catheter's distal end. The material between the inner and outer electrodes may be an insulator such as a dielectric with a high dielectric constant. This catheter configuration generates an electric field that bends around the tip of the catheter. The number, position, shape, and size of passive conductive elements may affect the shape of the electric field to improve ablation effectiveness and consistency. The active electrodes or passive conductors may be coupled to the inner surface of the catheter body, or they may be located inside the lumen so that fluid flows around them during ablation. ## Claims ### Claim 1 A tissue ablation catheter with passive conductive elements to shape electric fields, comprising: a tubular element comprising: a distal end configured to be placed proximal to a tissue to be ablated; a proximal end opposite said distal end; an inner surface surrounding a lumen; an outer surface; and, an electrical insulator between said inner surface and said outer surface; one or more inner electrodes within said lumen, each offset away from said distal end in a proximal direction towards said proximal end; one or more outer electrodes coupled to said outer surface; a controller coupled to said one or more inner electrodes and to said one or more outer electrodes and configured to: set voltages of said one or more inner electrodes and voltages of said one or more outer electrodes to generate an electric field outside said tubular element that induces ablation of said tissue to be ablated by electroporation; and, one or more passive conductive elements coupled to said tubular element, wherein: each passive conductive element of said one or more passive conductive elements is not coupled to said controller; and each passive conductive element comprises a conductive material, wherein charges within said conductive material move to modify said electric field. ### Claim 2 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein one or more of said one or more passive conductive elements are coupled to said inner surface and are offset away from said distal end in said proximal direction towards said proximal end. ### Claim 3 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein one or more of said one or more passive conductive elements are coupled to said outer surface. ### Claim 4 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein one or more of said one or more passive conductive elements are coupled to said distal end of said tubular element. ### Claim 5 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein said controller is further configured to: modify the voltages of said one or more inner electrodes and said one or more outer electrodes over time to change a direction of said electric field outside said tubular element over time. ### Claim 6 (depends on 5) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 5, wherein said controller is further configured to: set first voltages of said one or more inner electrodes and said one or more outer electrodes at a first time to generate a first average electric field vector in a region of said tissue to be ablated; set second voltages of said one or more inner electrodes and said one or more outer electrodes at a second time to generate a second average electric field vector in a second region of said tissue to be ablated; wherein an angular difference between said first average electric field vector and said second average electric field vector is at least 1 degree. ### Claim 7 (depends on 5) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 5, wherein: said controller is further configured to modify said voltages of said one or more inner electrodes and said one or more outer electrodes within a pulse time that is less than two times a membrane recovery time of said tissue to be ablated. ### Claim 8 (depends on 5) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 5, wherein: said controller is further configured to modify said voltages of said one or more inner electrodes and said one or more outer electrodes within a period that is less than or equal to 10 milliseconds. ### Claim 9 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein a shortest path of electrical current flowing from an inner electrode of said one or more inner electrodes to an outer electrode of said one or more outer electrodes is longer than a distance between said inner electrode and said outer electrode. ### Claim 10 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein said electrical insulator comprises a dielectric. ### Claim 11 (depends on 10) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 10, wherein said dielectric comprises aluminum nitride ceramic. ### Claim 12 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein conductivity of said electrical insulator is less than 0.1 micro-Siemens per centimeter. ### Claim 13 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein said controller is further configured to set a magnitude of a potential difference between at least one of said one or more inner electrodes and at least one of said one or more outer electrodes to greater than 1000 volts. ### Claim 14 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein said controller is further configured to set a magnitude of a potential difference between at least one of said one or more inner electrodes and at least one of said one or more outer electrodes to greater than 5000 volts. ### Claim 15 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein: at least one inner electrode of said one or more inner electrodes is located in a position within said lumen wherein fluid flowing through said lumen flows around edges of said at least one inner electrode. ### Claim 16 (depends on 15) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 15, wherein said at least one inner electrode has a shape that is cylindrical, spherical, or ellipsoidal. ### Claim 17 (depends on 1) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 1, wherein at least one passive conductive element of said one or more passive conductive elements is located in a position within said lumen wherein fluid flowing through said lumen flows around edges of said at least one passive conductive element. ### Claim 18 (depends on 17) The tissue ablation catheter with passive conductive elements to shape electric fields of claim 17, wherein said at least one passive conductive element has a shape that is cylindrical, spherical, or ellipsoidal.