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).

  • Publication number: 20170095290
    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: Application
    Filed: September 27, 2016
    Publication date: April 6, 2017
    Inventors: Marshall L. SHERMAN, Catherine R. CONDIE, Trenton J. REHBERGER, Steven J. FRAASCH, Mark T. STEWART
  • Publication number: 20170035499
    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: Application
    Filed: August 4, 2016
    Publication date: February 9, 2017
    Inventors: Mark T. STEWART, Steven J. FRAASCH
  • Patent number: 9554848
    Abstract: An ablation catheter assembly including an elongate catheter body having a proximal portion, a distal portion and a lumen therethrough. A helical structure associated with the catheter distal portion carries a plurality of independently operable electrodes and is transformable between a low-profile configuration wherein a straightening element is positioned in the lumen and an expanded configuration wherein the straightening element is at least partially retracted from the spiral structure. When the helical structure is in the expanded configuration, a laterally offset tip portion extends distally therefrom.
    Type: Grant
    Filed: November 26, 2013
    Date of Patent: January 31, 2017
    Assignee: Medtronic, Inc.
    Inventors: Mark T. Stewart, David Francischelli, Rahul Mehra, James Skarda
  • Publication number: 20160302925
    Abstract: A method for valve replacement or valve repair is disclosed comprising the steps of acquiring an anatomical image of a patient, correlating the image to the patient, guiding a valve replacement delivery member or a valve repair delivery member within the patient while tracking the position of the delivery member in the patient, positioning the valve replacement member or valve repair member in a desired position to place a valve or repair valve and removing the delivery member from the patient. In one aspect, a method and device are provided that involve imaging a native root using an interoperative technique, then introducing a device that is easily visualized in a chosen imaging modality.
    Type: Application
    Filed: April 14, 2016
    Publication date: October 20, 2016
    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: 20160278858
    Abstract: A medical system, including a catheter body, an elongate body disposed in the catheter body; an expandable element having a proximal portion coupled to the catheter body and a distal portion coupled to the elongate body, the distal portion of the expandable element defining the distal-most portion of the medical device; a mesh or array of longitudinal splines substantially surrounding the expandable element, at least a portion of the mesh or splines being electrically conductive; and a coolant source in fluid communication with the expandable element.
    Type: Application
    Filed: June 13, 2016
    Publication date: September 29, 2016
    Inventors: Mark T. STEWART, Jordon D. HONECK
  • Publication number: 20160262831
    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: May 25, 2016
    Publication date: September 15, 2016
    Inventors: Mark T. STEWART, Mark Allen BENSCOTER, Jon Virgil EVANS, Timothy G. LASKE, Gonzalo MARTINEZ
  • Patent number: 9387031
    Abstract: A medical system, including a catheter body, an elongate body disposed in the catheter body; an expandable element having a proximal portion coupled to the catheter body and a distal portion coupled to the elongate body, the distal portion of the expandable element defining the distal-most portion of the medical device; a mesh or array of longitudinal splines substantially surrounding the expandable element, at least a portion of the mesh or splines being electrically conductive; and a coolant source in fluid communication with the expandable element.
    Type: Grant
    Filed: July 29, 2011
    Date of Patent: July 12, 2016
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Mark T. Stewart, Jordon D. Honeck
  • Patent number: 9370311
    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: January 25, 2013
    Date of Patent: June 21, 2016
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Mark T. Stewart, Mark Allen Benscoter, Jon Virgil Evans, Timothy G. Laske, Gonzalo Martinez
  • Publication number: 20160166310
    Abstract: A method and system for mapping tissue and producing lesions for the treatment of cardiac arrhythmias in a non-thermal and optimal manner, minimizing the amount of energy required to selectively stun or ablate the target tissues. Energy may be delivered only at the moment(s) of best device position and proximity of an electrode to target tissue, and only during a time in the cardiac cycle determined to be optimal for reversible or irreversible effects. A method may include determining timing of the cardiac cycle and an optimal time within the cardiac cycle for energy delivery, evaluating proximity between at least one energy delivery electrode and the target tissue, and delivering pulsed field energy from the at least one energy delivery electrode to the target tissue when, during the optimal time for energy delivery, the at least one energy delivery electrode is in close proximity with the target tissue.
    Type: Application
    Filed: March 20, 2015
    Publication date: June 16, 2016
    Inventors: Mark T. STEWART, Catherine R. CONDIE, Jay L. KELLEY
  • Publication number: 20160157883
    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: December 2, 2015
    Publication date: June 9, 2016
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keogh, Hotaik Lee, Nadine B. Smith
  • Publication number: 20160128603
    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: Application
    Filed: January 15, 2016
    Publication date: May 12, 2016
    Inventors: Marshall L. SHERMAN, Catherine R. CONDIE, Mark T. STEWART
  • Publication number: 20160058505
    Abstract: Systems and methods for assessing tissue contact, including positioning an electrode adjacent a tissue region; delivering radiofrequency energy to the electrode, 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 electrode during the delivery of the radiofrequency energy; calculating a change in the impedance measurements over a pre-determined time period; and generating an alert if the calculated change is less than a pre-defined value.
    Type: Application
    Filed: November 6, 2015
    Publication date: March 3, 2016
    Inventors: Catherine R. CONDIE, Marshall L. SHERMAN, Mark T. STEWART
  • Publication number: 20160051324
    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: Application
    Filed: November 2, 2015
    Publication date: February 25, 2016
    Inventors: Mark T. STEWART, Jordon D. HONECK
  • Patent number: 9265557
    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 31, 2011
    Date of Patent: February 23, 2016
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Marshall L. Sherman, Catherine R. Condie, Mark T. Stewart
  • Patent number: 9227088
    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: May 3, 2010
    Date of Patent: January 5, 2016
    Assignee: Medtronic, Inc.
    Inventors: James B. Hissong, Mark T. Stewart, David E. Francischelli, James R. Keough, James R. Skarda, Hotaik Lee, Nadine B. Smith
  • Patent number: 9216050
    Abstract: A method and system for detecting microbubble formation during a radiofrequency ablation procedure. The method includes measuring an impedance of a pair of electrodes, at least one electrode in the pair of electrodes being coupled to a treatment assembly of a medical device. Radiofrequency ablation energy is transmitted between the pair of electrodes. The transmission of radiofrequency ablation energy between the pair of electrodes is terminated when after a predetermined period of time the measured impedance in either of the electrodes in the pair of electrodes is a predetermined percentage above a measured minimum impedance and a measured power is above a predetermined power threshold. An alert is generated indicating at least one of the formation and release of microbubbles proximate the pair of electrodes.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: December 22, 2015
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Catherine R. Condie, Marshall L. Sherman, Mark T. Stewart
  • Patent number: 9149198
    Abstract: A medical device including a catheter having a shaft with a distal portion; a first plurality of substantially hemispherical electrodes coupled to the distal portion; a second plurality of substantially hemispherical electrodes coupled to the shaft proximal of the first plurality, where the second plurality of electrodes are oriented substantially orthogonal to the first plurality of electrodes; and an additional electrode coupled to the shaft. A console may have a processor in electrical communication with the first and second plurality of electrodes and the reference electrode, the processor programmed to obtaining a monophasic action potential recording from at least one of the first and second plurality of electrodes.
    Type: Grant
    Filed: February 18, 2014
    Date of Patent: October 6, 2015
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Randell L. Werneth, Meleze Hocini, Mark T. Stewart, Dan Wittenberger, Timothy J. Corvi, Michael T. Lau, Vinod Sharma
  • Patent number: 9095350
    Abstract: Systems and methods for assessing electrode position, including positioning a plurality of electrodes within a heart and proximate a pulmonary vein; obtaining an impedance measurement from each of the plurality of electrodes; determining whether any of the plurality of electrodes is located within the pulmonary vein based at least in part on the obtained impedance measurements; and generating an indication if at least one of the plurality of electrodes is determined to be located within the pulmonary vein.
    Type: Grant
    Filed: May 1, 2012
    Date of Patent: August 4, 2015
    Assignee: Medtronic Ablation Frontiers LLC
    Inventors: Catherine R. Condie, Marshall L. Sherman, Mark T. Stewart
  • Patent number: 8998933
    Abstract: A surgical fastener clip for proximating tissue, the clip providing an undeflected state in which the clip comprises a center portion, a first leg, and a second leg. The center portion has a perimeter defining a circle-like shape. The legs project outwardly relative to the perimeter from a point of departure to a tip. Extension of each of the legs relative to the perimeter defines an identical wind direction that is either clockwise or counterclockwise. The clip optionally includes a linear cross-member extending across the perimeter. The surgical clip can be formed by a wire that is partially wound onto itself in a spiral-like fashion, with the center portion and the legs being co-planar in the undeflected state. During use, the clip is rotated, drawing tissue into the center portion. Systems incorporating the clip are also provided.
    Type: Grant
    Filed: February 28, 2008
    Date of Patent: April 7, 2015
    Assignee: Medtronic, Inc.
    Inventors: Paul T. Rothstein, Cynthia T. Clague, Michael M. Green, Damian A. Jelich, Eric A. Meyer, Mark T. Stewart, Chris M. Coppin, Rany Huynh, Mark W. Torrianni, Asha S. Nayak, John R. Liddicoat, Timothy G. Laske
  • Patent number: 8926635
    Abstract: A novel occluder application and clip device for treatment of embolic stroke caused by atrial fibrillation uses multiple sutures in a non directional handle to affix the occlusion device to the applicator and manipulate the occluder from an open and receiving position to a closed and occluding position. The occluder is retained in place by a clamping means related to locks retainers, resilient material or otherwise. An actuator mechanism is used to manipulate the occluder to a locked or occluding position. The applicator with the occluder attached has a low profile and remote manipulations to allow the occluder to be delivered to the clamping location within a patient through a small incision or delivery port such as a trocar cannula or the like.
    Type: Grant
    Filed: October 2, 2009
    Date of Patent: January 6, 2015
    Assignee: Medtronic, Inc.
    Inventors: David E. Francischelli, Roderick E. Briscoe, Leonard H. Leuer, Daniel C. Haeg, Tom P. Daigle, David Kim, Mark T. Stewart, Andrew L. Olson, Patrick J. Cloutier, Christopher W. Smith, Michael J. Hobday, Tessy Kanayinkal, Douglas H. Gubbin, Paul T. Rothstein, Joseph E. Cardinal, Jessica L. Foley, Christopher J. Plott