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: 10166071
    Abstract: A method of assessing a tissue ablation treatment, including positioning a medical device adjacent a target tissue; measuring a first impedance magnitude a first frequency with the medical device; measuring a first impedance phase at a second frequency with the medical device; ablating at least a portion of the target tissue with the medical device; measuring at second impedance magnitude at a third frequency with the medical device; measuring a second impedance phase at a fourth frequency with the medical device; comparing at least one of (i) the first and second impedance magnitudes and (ii) the first and second impedance phases; and providing an indication of the efficacy of the ablation treatment based at least in part on the comparison.
    Type: Grant
    Filed: January 15, 2016
    Date of Patent: January 1, 2019
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Marshall L. Sherman, Catherine R. Condie, Mark T. Stewart
  • Publication number: 20180325399
    Abstract: The present invention relates to a method, device, and system for improved mapping and/or ablation of a tissue. The device may generally include an elongate body and a distal assembly affixed to the elongate body that includes a treatment electrode having a conductive mapping region and a selectively conductive ablation region that is conductive of high-frequency current and substantially non-conductive of low-frequency current. Alternatively, the device may generally include a treatment electrode having a conductive mapping or ablation region and a region that is coated with an electrically insulated but thermally conductive layer.
    Type: Application
    Filed: July 19, 2018
    Publication date: November 15, 2018
    Inventors: Mark T. STEWART, Mark Allen BENSCOTER, Jon Virgil EVANS, Timothy G. LASKE, Gonzalo MARTINEZ
  • Publication number: 20180303543
    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: April 24, 2017
    Publication date: October 25, 2018
    Inventors: Mark T. STEWART, Brian T. HOWARD, Steven J. FRAASCH
  • Publication number: 20180263651
    Abstract: A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.
    Type: Application
    Filed: March 12, 2018
    Publication date: September 20, 2018
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keogh, Hotaik Lee, Nadine B. Smith, James R. Skarda
  • Publication number: 20180228528
    Abstract: Systems and methods to confirm safe delivery of treatment energy to a patient by identifying a presence of a fault in an energy delivery pathway and identifying a location of the fault within the device. The system includes a processing unit configured to calculate blood impedances external to the device based on known impedance characteristics of the device, and then to calculate impedances within the device during energy delivery based on the calculated blood impedances. The processing unit prevents the delivery of energy in an energy delivery pathway that is determined to be compromised. The processing unit is also configured to compare times for two different frequencies to travel a predetermined distance, the difference in the times corresponding to a location of a fault within the energy delivery pathway.
    Type: Application
    Filed: February 14, 2017
    Publication date: August 16, 2018
    Inventors: Steven J. FRAASCH, Catherine R. CONDIE, Trenton J. REHBERGER, Mark T. STEWART, Qin ZHANG
  • Publication number: 20180221078
    Abstract: A method of determining a pulsed field ablation waveform parameter for creating a desired lesion characteristic in cardiac tissue. The method of provides an electrosurgical generator configured to deliver electroporation pulses, the generator configured to: load predetermined waveform parameters (yi); load predetermined modeling data (xi); accept entry of a user inputted desired lesion characteristic (ui); and determine at least one corresponding pulsed field ablation waveform parameter based on (ui), (yi); and (xi).
    Type: Application
    Filed: February 8, 2017
    Publication date: August 9, 2018
    Inventors: Brian T. HOWARD, Steven J. FRAASCH, Mark T. STEWART, John VANDANACKER
  • Patent number: 10039467
    Abstract: The present invention relates to a method, device, and system for improved mapping and/or ablation of a tissue. The device may generally include an elongate body and a distal assembly affixed to the elongate body that includes a treatment electrode having a conductive mapping region and a selectively conductive ablation region that is conductive of high-frequency current and substantially non-conductive of low-frequency current. Alternatively, the device may generally include a treatment electrode having a conductive mapping or ablation region and a region that is coated with an electrically insulated but thermally conductive layer.
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: August 7, 2018
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Mark T. Stewart, Mark Allen Benscoter, Jon Virgil Evans, Timothy G. Laske, Gonzalo Martinez
  • Patent number: 10039502
    Abstract: A method of mapping electrophysiological information, including receiving imaging information for a tissue region; receiving a monophasic action potential signal from the tissue region; assigning a value corresponding to a depolarization segment of the monophasic action potential signal; receiving location information associated with the monophasic action potential signal; and generating an image based on the imaging information, the assigned value, and the location information.
    Type: Grant
    Filed: April 12, 2011
    Date of Patent: August 7, 2018
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Mark T. Stewart, Scott W. Davie, Giles Desrochers
  • Publication number: 20180214202
    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: January 27, 2017
    Publication date: August 2, 2018
    Inventors: Brian T. HOWARD, Mark T. STEWART, Damijan MIKLAVCIC, Bushan K. PURUSHOTHAMAN, Jeremy M. STIMACK
  • Publication number: 20180214195
    Abstract: A system and method for the safe delivery of treatment energy to a patient, which includes verification of system integrity before, during, or after the delivery of treatment energy and provides several mechanisms for rapid termination of the delivery of potentially harmful energy to the patient when a fault condition in the device and/or system is identified. The system may include an energy generator having processing circuitry to determine if there is a fault condition in the system and to automatically terminate a delivery of treatment energy when the processing circuitry determines there is a fault condition. The method may generally include performing a series of pre-checks, synchronizing a treatment energy delivery to the proper segment of the heart's depolarization pattern, configuring the system for treatment energy delivery, delivering the treatment energy, and performing post-treatment evaluation.
    Type: Application
    Filed: January 27, 2017
    Publication date: August 2, 2018
    Inventors: Steven J. FRAASCH, Catherine R. CONDIE, Brian T. HOWARD, Louis JACOB, Paul S. LAM, Trenton J. REHBERGER, Mark T. STEWART, Qin ZHANG
  • Patent number: 9949831
    Abstract: A method for determining whether a medical device is appropriate for implanting into a cardiovascular conduit of a patient is disclosed comprising imaging a first section of the conduit of the patient into which the medical device is to be implanted during a first expanded state occurring at a first portion of a heart rhythm; reimaging the first section of the conduit of the patient during a first contracted state occurring at a second portion of the heart rhythm; deriving, from the imaging and the reimaging, dimensional characteristics of the first section of the conduit; and determining whether the medical device is appropriate for implantation in the first section of conduit based on the derived dimensional characteristics. The first section of the conduit includes a sizing device providing a selected radial force on the patient.
    Type: Grant
    Filed: February 6, 2014
    Date of Patent: April 24, 2018
    Assignee: Medtronics, Inc.
    Inventors: James R. Keogh, Timothy R. Ryan, Carol E. Eberhardt, Mark T. Stewart, James R. Skarda, Timothy G. Laske, Alexander J. Hill, Jack D. Lemmon, David E. Francischelli
  • Publication number: 20180098810
    Abstract: A medical method is provided, including a medical device having a distal assembly including at least one electrode and at least one treatment element, the medical device generating information regarding at least one of a physiological measurement and an operational parameter of the medical device; a plurality of surface electrodes affixable to a skin of the patient, wherein the surface electrodes are in electrical communication with the distal assembly to obtain position information of the medical device; and a processor pairing the position information and the at least one of a physiological measurement and an operational parameter of the medical device.
    Type: Application
    Filed: December 13, 2017
    Publication date: April 12, 2018
    Inventors: Randell L. WERNETH, Marshall SHERMAN, Mark T. STEWART, J. Christopher FLAHERTY
  • Patent number: 9931134
    Abstract: A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.
    Type: Grant
    Filed: July 5, 2017
    Date of Patent: April 3, 2018
    Assignee: Medtronic, Inc.
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keogh, Hotaik Lee, Nadine B. Smith, James R. Skarda
  • Patent number: 9867661
    Abstract: A medical method is provided, including a medical device having a distal assembly including at least one electrode and at least one treatment element, the medical device generating information regarding at least one of a physiological measurement and an operational parameter of the medical device; a plurality of surface electrodes affixable to a skin of the patient, wherein the surface electrodes are in electrical communication with the distal assembly to obtain position information of the medical device; and a processor pairing the position information and the at least one of a physiological measurement and an operational parameter of the medical device.
    Type: Grant
    Filed: August 26, 2014
    Date of Patent: January 16, 2018
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Randell L. Werneth, Marshall Sherman, Mark T. Stewart, J. Christopher Flaherty
  • Publication number: 20170296217
    Abstract: A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.
    Type: Application
    Filed: July 5, 2017
    Publication date: October 19, 2017
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keogh, Hotaik Lee, Nadine B. Smith, James R. Skarda
  • Patent number: 9757190
    Abstract: A method for manufacturing a distal portion of a mapping and/or ablation device with fewer components and manufacturing steps than are required for presently known devices. The method generally includes aligning one or more electrodes and electrode wires within a housing mold, overmolding a biocompatible material over the one or more wires and a portion of each of the one or more electrodes, creating a housing component that integrates a dome component and an insulation component. Alternatively, the method generally includes aligning one or more wires within a housing mold so that at least a portion of each wire protrudes from the mold, overmolding a biocompatible material over the one or more wires, thus creating a housing component that integrates a dome component and insulation component. The protruding wire portions are cleaved off and at least a portion of the housing component is coated with a layer of conductive material.
    Type: Grant
    Filed: January 25, 2013
    Date of Patent: September 12, 2017
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Jon Virgil Evans, George Wedell Gullickson, Mark T. Stewart
  • Patent number: 9750570
    Abstract: Systems and methods for assessing tissue contact, including positioning a plurality of electrodes adjacent a tissue region; delivering radiofrequency energy to the plurality of electrodes, wherein the delivered radiofrequency energy is sufficient to ablate at least a portion of the tissue region; obtaining a plurality of impedance measurements from the plurality of electrodes during the delivery of the radiofrequency energy; calculating a change in the impedance measurements for each of the plurality of electrodes over a pre-determined time period; comparing the calculated change for at least one of the plurality of electrodes to the calculated change in at least one other of the plurality of electrode to determine if there is significant variation in the calculated changes; and terminating the delivery of radiofrequency energy to at least one of the plurality if there is significant variation in the calculated changes.
    Type: Grant
    Filed: November 6, 2015
    Date of Patent: September 5, 2017
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Catherine R. Condie, Marshall L. Sherman, Mark T. Stewart
  • Patent number: 9724119
    Abstract: A device and method for ablating tissue is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding an ablating member within the patient while tracking the position of the ablating member in the patient, positioning the ablating member in a desired position to ablate tissue, emitting ablating energy from the ablating member to form an ablated tissue area and removing the ablating member from the patient.
    Type: Grant
    Filed: December 2, 2015
    Date of Patent: August 8, 2017
    Assignee: Medtronic, Inc.
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keogh, Hotaik Lee, Nadine B. Smith, James R. Skarda
  • Patent number: 9681911
    Abstract: Device and method for sub-xiphoid ablation of patient tissue. A sub-xiphoid access clamp has a handle, an elongate neck coupled to the handle and first and second opposing jaws. The first and second opposing jaws have first and second opposing relief segments being generally co-planar and concave with respect to one another to form a void therebetween, and first and second opposing elongate ablation elements positioned along the first and second opposing jaws and distal of the first and second opposing relief segments relative to the handle. The first and second opposing jaws are articulate between a closed position and an open position to admit, at least in part, a second portion of tissue of the patient within the void created by the first and second opposing relief segments while the first portion of tissue is positioned between the first and second ablation elements in the closed position.
    Type: Grant
    Filed: February 25, 2014
    Date of Patent: June 20, 2017
    Assignee: Medtronic, Inc.
    Inventors: Mark T. Stewart, Tom P. Daigle, David E. Francischelli, John R. Liddicoat, Paul T. Rothstein, Steven F. Bolling
  • Patent number: 9656063
    Abstract: A method of placing an electrical lead of an implantable cardiac device inside a heart of a patient. The method includes securing a tool to an atrial appendage of the heart to hold onto the atrial appendage, piercing the atrial appendage, and creating an aperture in the atrial appendage while holding the atrial appendage with the tool. The method also includes moving a distal end of the electrical lead into the heart through the aperture in the atrial appendage and into a ventricle of the heart. Furthermore, the method includes coupling the distal end of the electrical lead to cardiac tissue in the ventricle and delivering an electrical signal to the cardiac tissue in the ventricle of the heart to maintain a predetermined heartbeat of the heart.
    Type: Grant
    Filed: April 2, 2013
    Date of Patent: May 23, 2017
    Assignee: Medtronic, Inc.
    Inventors: James F Kelley, Zhongping Yang, Mark T Stewart