Patents by Inventor Mark T. Stewart

Mark T. Stewart has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11918280
    Abstract: Methods and systems for combining ablation therapy with navigation of the ablation device. An ablation system may be configured for use with one of two methods to prevent loss of navigation signals during ablation energy delivery. In the first method, ablation energy signals are filtered from the navigation signal. In the second method, the delivery of ablation energy is sequenced with the delivery of navigation energy such that ablation energy and navigation energy are not delivered at the same time and navigation signals received by the system are time-division multiplexed to reconstruct the navigation signals and determine a location of the device within the patient.
    Type: Grant
    Filed: June 18, 2020
    Date of Patent: March 5, 2024
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Marshall L. Sherman, Catherine R. Condie, Trenton J. Rehberger, Steven J. Fraasch, Mark T. Stewart
  • Publication number: 20230414277
    Abstract: A medical device includes an elongate body, an expandable treatment element, a plurality of flexible shafts, and a plurality of electrodes. The elongate body has a proximal portion and a distal portion opposite the proximal portion. The expandable treatment element is coupled to the elongate body to receive a fluid and, in some examples, is anchored to the plurality of flexible shafts with a plurality of retention elements. In some examples, each flexible shaft of the plurality of flexible shafts has a braided configuration. Each electrode of the plurality of electrodes is attached and electrically coupled to a respective flexible shaft of the plurality of flexible shafts.
    Type: Application
    Filed: June 21, 2023
    Publication date: December 28, 2023
    Inventors: Brian J. Kelly, Gavin J. Kenny, Brian T. Howard, Timothy G. Laske, Andrzej M. Malewicz, Mark T. Stewart
  • Publication number: 20230414276
    Abstract: A method and a pulsed electric field (PEF) ablation instrument are provided. According to one aspect, a method in a PFA generator includes receiving electrical responses for each of at least one non-therapeutic waveform. The process also includes determining an electric field distribution based at least in part on the received electrical responses. The process further includes selecting a non-therapeutic waveform that produces an electric field distribution that satisfies criteria. The process also includes mapping the selected non-therapeutic waveform to an ablative waveform.
    Type: Application
    Filed: June 21, 2023
    Publication date: December 28, 2023
    Inventors: Timothy G. Laske, Qingguo Zeng, Qing Lou, Mark T. Stewart, Brian T. Howard, Anthony W. Rorvick, Gregory S. Brumfield
  • Publication number: 20230355301
    Abstract: An example system for use in ablating target tissue includes memory configured to store anatomical and/or physiological information of a patient and processing circuitry communicatively coupled to the memory. The processing circuitry is configured to, based on the anatomical information and/or the physiological information, determine ablation parameters, the ablation parameters including a suggested positioning of at least energy delivery element of at least one catheter and/or an amount of energy to be delivered via the at least one energy delivery element to the target tissue during ablation. The processing circuitry is configured to output, for display, a representation of at least one of a suggested positioning of the at least one energy delivery element during the ablation, a representation of the target tissue, or a representation of the predicted tissue volume that will be ablated after delivery of ablation energy.
    Type: Application
    Filed: April 11, 2023
    Publication date: November 9, 2023
    Inventors: Mary A. Beckman, Heather L. O'Connell, Timothy G. Laske, Mark T. Stewart, Brian T. Howard, Lars M. Mattison, Megan M. Schmidt, Sarah E. Ahlberg
  • Publication number: 20230329784
    Abstract: A medical device comprising an elongate body having a proximal portion, a distal portion, a distal end, a longitudinal axis, and a radius, a plurality of deployable arms, the deployable arms being movably coupled to the elongate body, and at least one arm from the plurality of deployable arms having at least one electrically conductive surface. The plurality of deployable arms being movable from a collapsed configuration to an expanded configuration. In the collapsed configuration, the plurality of deployable arms are approximately parallel to the longitudinal axis. In the expanded configuration, the at least one electrically conductive surface is distal facing and is positioned radially from the longitudinal axis by a distance that is greater than the radius of the elongate body.
    Type: Application
    Filed: June 23, 2023
    Publication date: October 19, 2023
    Inventors: Mark T. Stewart, Jordon D. Honeck
  • Publication number: 20230310069
    Abstract: An example method for performing pulsed field ablation (PFA) includes determining, by a controller connected to a particular catheter and at a first time, to perform PFA using a linear PFA mode; responsive to determining to use the linear PFA mode, outputting, by the controller and to electrodes of the particular catheter, energy to cause the electrodes to generate a field with a geometry that is linear along an active portion of the particular catheter; determining, by the controller and at a second time, to perform PFA using a focal PFA mode; and responsive to determining to use the focal PFA mode, outputting, by the controller and to the electrodes of the particular catheter, energy to cause the electrodes to generate a field with a geometry that is focused at a tip of the particular catheter.
    Type: Application
    Filed: March 14, 2023
    Publication date: October 5, 2023
    Inventors: Mark T. Stewart, Brian T. Howard
  • Publication number: 20230310072
    Abstract: A method and system for directed pulsed electric field (PEF) ablation are disclosed. In one aspect, an irreversible electroporation (IRE) system includes processing circuitry configured to select a first set of electrodes positioned to produce a first electric field in a first direction in a region of tissue of a patient, and select a second set of electrodes positioned to produce a second electric field in a second direction in the region of tissue. The processing circuitry is configured to transmit a first IRE pulse to the first set of electrodes to cause emission of the first electric field and transmit a second IRE pulse to the second set of electrodes to cause emission of the second electric field. The first IRE pulse and the second IRE pulse are transmitted by the processing circuitry to control an electric field gradient along a path within the region of tissue.
    Type: Application
    Filed: March 27, 2023
    Publication date: October 5, 2023
    Inventors: Mark T. Stewart, Brian T. Howard, Timothy G. Laske
  • Publication number: 20230310061
    Abstract: A method of delivering pulsed electric field energy to perform ablation of a tissue includes providing a pulse train to an electrode. The pulse train may include a first set of pulses with a first pulse width to generate first electric field and a second set of pulses with a second pulse width greater than the first pulse width to generate a second electric field. The electrode may be positioned at a same position during generation of the first electric field and the second electric field. The first electric field may be configured to have a higher electroporation effect on the first elongated cells having a first orientation than on second elongated cells having a second orientation. The second electric field may be configured to have a higher electroporation effect on the second cells than on the first cells.
    Type: Application
    Filed: April 4, 2023
    Publication date: October 5, 2023
    Inventors: Mark T. Stewart, Lars M. Mattison, Brian T. Howard, Damijan Miklavcic, Tadej Kotnik, Janja Dermol-Cerne, Tina Batista Napotnik
  • Publication number: 20230310068
    Abstract: An example catheter for performing pulsed field ablation (PFA) includes: an elongated structure defining a longitudinal axis; a plurality of electrodes carried on a distal portion of the elongated structure, the plurality of electrodes comprising: a tip electrode positioned at a distal tip of the elongated structure; a tip ring electrode adjacent to the tip electrode; a pair of ring electrodes; and one or more additional electrodes, wherein the pair of ring electrodes is disposed longitudinally along the elongated structure between the tip ring electrode and the one or more additional electrodes.
    Type: Application
    Filed: March 14, 2023
    Publication date: October 5, 2023
    Inventors: Mark T. Stewart, Brian T. Howard
  • Publication number: 20230277242
    Abstract: A medical device comprising an elongate body having a proximal portion, a distal portion, a distal end, a longitudinal axis, and a radius, a plurality of deployable arms, the deployable arms being movably coupled to the elongate body, and at least one arm from the plurality of deployable arms having at least one electrically conductive surface. The plurality of deployable arms being movable from a collapsed configuration to an expanded configuration. In the collapsed configuration, the plurality of deployable arms are approximately parallel to the longitudinal axis. In the expanded configuration, the at least one electrically conductive surface is distal facing and is positioned radially from the longitudinal axis by a distance that is greater than the radius of the elongate body.
    Type: Application
    Filed: May 12, 2023
    Publication date: September 7, 2023
    Inventors: Mark T. Stewart, Jordon D. Honeck
  • Patent number: 11744642
    Abstract: A device, system, and method for optically evaluating and treating or ablating tissue. Specifically, device, system, and method allow for the optical and/or electrical evaluation of tissue at the same location(s) at which ablation or treatment or ablation energy is delivered. This allows for a more accurate evaluation of lesion formation and tissue condition before, during, and/or after a treatment or ablation procedure. In one embodiment, a device for performing a medical procedure includes an elongate body including a proximal portion, a distal portion having a distal end, and a longitudinal axis, and a distal tip electrode at the elongate body distal end, the tip electrode being optically transparent and electrically conductive. The device may also include optical windows in the elongate body aligned with one or more transparent lateral electrodes for optically interrogating tissue and/or for delivering treatment or ablation energy to tissue.
    Type: Grant
    Filed: February 1, 2021
    Date of Patent: September 5, 2023
    Assignee: Medtronic, Inc.
    Inventors: Gonzalo Martinez, Timothy G. Laske, Mark T. Stewart
  • Patent number: 11701169
    Abstract: A method for ablating tissue by applying at least one pulse train of pulsed-field energy. The method includes delivering a pulse train of energy having a predetermined frequency to cardiac tissue, the pulse train including at least 60 pulses, an inter-phase delay between 0 ?s and 5 ?s, an inter-pulse delay of at least 5 ?s, and a pulse width of 5 ?s.
    Type: Grant
    Filed: December 9, 2019
    Date of Patent: July 18, 2023
    Assignee: Medtronic, Inc.
    Inventors: Mark T. Stewart, Steven J. Fraasch
  • Patent number: 11633230
    Abstract: A medical system, including a medical device having a plurality of deployable arms, and at least one electrode on at least one of the plurality of arms; and an electric signal generator in communication with the medical device, the electric signal generator programmed to deliver pulsed energy to the medical device sufficient to induce irreversible electroporation ablation.
    Type: Grant
    Filed: June 8, 2020
    Date of Patent: April 25, 2023
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Mark T. Stewart, Jordon D. Honeck
  • Patent number: 11612424
    Abstract: Methods and systems for monitoring and modifying pulsed field ablation (PFA) energy delivery to prevent patient safety risks and/or delivery device failure. In particular, some embodiments provide methods and systems for detecting and preventing arcs and arc-induced plasma, and their causal events, during delivery of pulsed field ablation energy, as well as methods and systems for identifying conditions leading to potential delivery device failure and correcting charge imbalance or asymmetry.
    Type: Grant
    Filed: November 7, 2019
    Date of Patent: March 28, 2023
    Assignee: Medtronic, Inc.
    Inventors: Steven J. Fraasch, Trenton J. Rehberger, Qin Zhang, Lynn A. Davenport, Steven V. Ramberg, Brian T. Howard, Mark T. Stewart, Alexander J. Hill, John Vandanacker
  • Publication number: 20220338925
    Abstract: A device, system, and method for delivering energy to tissue. In particular, the present invention relates to a system and method for enhancing lesion formation without arrhythmogenic effects within relatively thick target tissues, such as the ventricles of the heart. In one embodiment, charge-neutral pulses and non-charge-neutral pulses may be delivered to induce the formation of electrolytic compounds that enhance cell death at the treatment site. Additionally or alternatively, tissue at the treatment site may be heated to sub-lethal temperature before ablating the tissue.
    Type: Application
    Filed: July 11, 2022
    Publication date: October 27, 2022
    Inventors: Mark T. Stewart, Brian T. Howard, Steven J. Fraasch
  • Publication number: 20220313355
    Abstract: Methods, systems, and devices for enhancing the efficiency and efficacy of energy delivery and tissue mapping. One system includes a treatment element having a plurality of electrodes and an energy generator that is configured to deliver electric energy pulses to the electrodes in a variety of patterns. For example, electrodes may be arranged in closely spaced pairs. The energy generator may deliver mapping energy to each electrode in each pair individually to map tissue and may deliver ablation energy to the electrodes in each pair together, such that each pair is treated like a single electrode, to deliver ablation energy, such as bipolar ablation energy between adjacent pairs. One system includes at least one concave electrode, the configuration of which concentrates the energy and drives it deeper into the tissue. One system includes neutral electrodes between active electrodes, the energy generator selectively coupling the neutral electrodes to alter the ablation pattern.
    Type: Application
    Filed: June 20, 2022
    Publication date: October 6, 2022
    Inventors: Brian T. Howard, Mark T. Stewart, Damijan Miklavcic, Bushan K. Purushothaman, Jeremy M. Stimack
  • Patent number: 11457976
    Abstract: A medical device for directionally focusing energy to a treatment site, the medical device including a shaft having an elongated body defining a proximal portion and a distal portion opposite the proximal portion, the distal portion including at least one electrode having a contact portion and a permeable sheath at least partially surrounding the at least one electrode, the permeable sheath and the at least one electrode defining an insulation cavity, the permeable sheath being impermeable to an insulation material introduced to the insulation cavity from a fluid source configured to be coupled to the shaft.
    Type: Grant
    Filed: January 8, 2019
    Date of Patent: October 4, 2022
    Assignee: Medtronic, Inc.
    Inventors: Mark T. Stewart, Brian T. Howard
  • Publication number: 20220296295
    Abstract: A medical device including an elongate body having a proximal portion and a distal portion. A plurality of active electrodes is coupled to the distal portion of the elongate body and being configured to electrically couple to a source of pulsed electric field energy. At least one passive electrode is coupled to the elongate body and is not configured to electrically couple to the source of pulsed electric field energy, the at least one passive electrode being configured to passively extend or focus an electric field generated by the plurality of active electrodes.
    Type: Application
    Filed: March 17, 2022
    Publication date: September 22, 2022
    Inventors: Brian T. Howard, Timothy G. Laske, Kenneth C. Gardeski, Gonzalo Martinez, Mark T. Stewart, Lars M. Mattison
  • Publication number: 20220280229
    Abstract: A method and pulsed field ablation (PFA) system configured to provide variable impedance paths for delivery of electric fields to patient tissue using a PFA catheter are disclosed. According to one aspect, a method includes determining a current for each of a plurality of circuit paths, each circuit path including two electrodes. Each current may be determined based at least in part on: a desired voltage between the two electrodes; a tissue impedance between the two electrodes; and a parasitic impedance associated with the circuit path. The method also includes determining at least one of an excitation voltage and an input resistance for each circuit path of the plurality of circuit paths based at least in part on the determined current for the circuit path, parasitic impedances associated with the circuit path and a tissue impedance between the two electrodes in the circuit path.
    Type: Application
    Filed: March 1, 2022
    Publication date: September 8, 2022
    Inventors: Brian T. Howard, Steven J. Fraasch, Gonzalo Martinez, Mark T. Stewart, Sara A. Frantz, Lars M. Mattison
  • Publication number: 20220257938
    Abstract: A method, system, and device for electroporation. A method for electroporating tissue, the method may include positioning a medical device having a plurality of electrodes proximate an area of tissue, delivering electroporation energy to the plurality of electrodes with an energy generator, receiving data from the plurality of electrodes, determining whether an alert condition is present based upon the data received from the plurality of electrodes, and at least one of cease a delivery of electroporation energy to the plurality of electrodes and prevent the delivery of electroporation energy to the plurality of electrodes when a processing circuitry determines that an alert condition is present.
    Type: Application
    Filed: April 28, 2022
    Publication date: August 18, 2022
    Inventors: Mark T. STEWART, Brian T. HOWARD