Patents Represented by Attorney, Agent or Law Firm Reed A. Duthler
  • Method and apparatus for R-F ablation
    Patent number: 5431649
    Abstract: An ablation catheter and a method of performing cardiac ablation. The catheter is provided with a hollow, helical electrode, which is screwed into cardiac tissue at a desired ablation site and connected to a source of R-F electrical energy to ablate the tissue adjacent the electrode. Prior to ablation, a conductive fluid may be injected through the hollow needle, both to provide for cooling of the tissue adjacent the needle and to increase the conductivity of the tissue in the area of the electrode.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: July 11, 1995
    Assignee: Medtronic, Inc.
    Inventors: Peter M. J. Mulier, Michael F. Hoey
  • Pacemaker
    Patent number: 5431695
    Abstract: An implantable medical device including a hermetic housing containing an electronic circuit, such as a cardiac pacemaker. The electronic circuit may be coupled to a medical lead by means of a connector module which is formed as part of a molded, resilient shroud, extending around the circumference of the hermetic container.
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: July 11, 1995
    Assignee: Medtronic, Inc.
    Inventors: Craig L. Wiklund, Daniel A. Lyons, Eric M. Rieder, John E. Nicholson, Randy C. Schulhauser
  • Active can emulator and method of use
    Patent number: 5411539
    Abstract: An active can emulator for emulating the electrical and dimensional characteristics of an implantable pulse generator of the type having a hermetically sealed housing configured to operate as an active electrode and a connector block for receiving and connecting with a lead extending to a second active electrode. The emulator comprises a reusable, sterilizable, conductive can conforming to the dimensional characteristics of the hermetically sealed housing of the implantable pulse generator and having a first electrical and mechanical connector and a disposable lead having a second electrical and mechanical connector for mating attachment with the first connector formed as part of a header configured to conform to the dimensional characteristics of the connector block of the emulated pulse generator.
    Type: Grant
    Filed: August 31, 1993
    Date of Patent: May 2, 1995
    Assignee: Medtronic, Inc.
    Inventor: Hans J. Neisz
  • Method and apparatus for control of A-V interval
    Patent number: 5411531
    Abstract: A device for controlling the duration of A-V conduction intervals in a patient's heart. Stimulation of the AV nodal fat pad is employed to maintain the durations of the A-V conduction intervals within a desired interval range, which may vary as a function of sensed heart rate or other physiologic parameter. AV nodal fat pad stimulation may also be triggered in response to defined heart rhythms such as a rapid rate or the occurrence of PVC's, to terminate or prevent induction of arrhythmias.
    Type: Grant
    Filed: September 23, 1993
    Date of Patent: May 2, 1995
    Assignee: Medtronic, Inc.
    Inventors: Michael R. S. Hill, Rahul Mehra
  • Method and apparatus for synchronization of atrial defibrillation pulses
    Patent number: 5411524
    Abstract: A method and apparatus for detecting and treating atrial fibrillation. In response to detecting atrial fibrillation, the device derives an escape interval based on one or more preceding intervals between ventricular depolarizations. The escape interval is initiated in response to a ventricular depolarization, and in response to the expiration of the escape interval, an atrial cardioversion pulse is delivered. In one embodiment of the invention, the cardioverting pulse is delivered immediately upon expiration of the derived escape interval. In a second embodiment of the invention, a ventricular pacing pulse is delivered on expiration of the escape interval, with an atrial cardioversion pulse following after a short delay.
    Type: Grant
    Filed: November 2, 1993
    Date of Patent: May 2, 1995
    Assignee: Medtronic, Inc.
    Inventor: Mehra Rahul
  • Waveform discriminator for cardiac stimulation devices
    Patent number: 5411529
    Abstract: An apparatus for producing signals indicative of power levels of depolarizations of heart tissue, particularly adapted for use in an implantable antiarrhythmia device or an implantable pacemaker. The device distinguishes between the power level of sensed depolarization signals in order to distinguish between different types of depolarization waveforms. In particular, the measured power level of the sensed depolarizations may be employed to distinguish between normally conducted and ectopic beats, for use in controlling the operation of an implantable antiarrhythmia device such as an implantable pacemaker/cardioverter/defibrillator or for use in controlling the operation of a bradycardia pacemaker.
    Type: Grant
    Filed: September 13, 1993
    Date of Patent: May 2, 1995
    Assignee: Medtronic, Inc.
    Inventor: Terrence R. Hudrlik
  • Methods for measurement of arterial blood flow
    Patent number: 5409009
    Abstract: A sensor for measurement of one or more parameters of arterial blood flow, located on a transvenously inserted lead. The sensor may be inserted into a vein that is anatomically adjacent to the artery in which blood flow parameters are to be monitored, rather than into the artery itself. The sensor may take the form of a set of spaced electrodes for impedance plethysmography, a piezoelectric pulse sensor or a pulse Doppler sensor for detecting arterial blood flow. By measuring arterial blood flow from an adjacent vein, problems associated with insertion of the sensor into the arterial system may be avoided. The sensor may be used to control the characteristics of an implantable device, such as an implantable pacemaker/cardioverter/defibrillator, an implantable drug dispenser or a rate responsive pacemaker.
    Type: Grant
    Filed: March 18, 1994
    Date of Patent: April 25, 1995
    Assignee: Medtronic, Inc.
    Inventor: Walter H. Olson
  • Transvenous defibrillation lead and method of use
    Patent number: 5405374
    Abstract: A defibrillation lead for location in a human heart, having an elongated lead body defining a generally straight segment extending from its proximal end and a curved segment extending distally from the straight segment. The curved segment has a sigmoidal configuration including a two or more alternating, generally coplanar curves, and carries an elongated defibrillation electrode extending along its length. A stylet is provided for straightening the curved segment prior to implant.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: April 11, 1995
    Assignee: Medtronic, Inc.
    Inventor: Paul M. Stein
  • Method and apparatus for ablation
    Patent number: 5405376
    Abstract: An ablation catheter and a method of performing cardiac ablation using alcohol or other ablating agents. The catheter is provided with a helical hollow needle, which is screwed into heart tissue, after which the ablating agent is delivered through the needle. Prior to ablation, the catheter may be employed to locate an appropriate ablation site or to assess the suitability of an identified ablation site by injection of a exitability reducing agent such as lidocaine, through the hollow needle, followed by a determination of whether the arrhythmia intended to be treated as temporarily terminated.
    Type: Grant
    Filed: August 27, 1993
    Date of Patent: April 11, 1995
    Assignee: Medtronic, Inc.
    Inventors: Peter M. J. Mulier, Michael F. Hoey
  • Method and apparatus for detection and treatment of tachycardia and fibrillation
    Patent number: 5403352
    Abstract: An automatic implantable device for detecting and differentiating between tachyarrhythmias in order to therapeutically stimulate the heart in response thereto, particularly for distinguishing fibrillation from tachycardia and to provide appropriate therapies for each condition. The event intervals between successive heart depolarizations are measured, stored and classified as within fibrillation or tachycardia interval ranges. The numbers of intervals falling within the fibrillation and tachycardia interval ranges are employed to distinguish fibrillation from tachycardia. The number of intervals required to detect and discriminate between tachycardia and fibrillation in situations where the tachyarrhythmia includes intervals in both interval ranges is reduced by adjusting the interval ranges as a function of the relative distribution of measured intervals within the interval ranges.
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: April 4, 1995
    Assignee: Medtronic, Inc.
    Inventor: Martin A. Rossing
  • Method and apparatus for prevention of atrial tachy arrhythmias
    Patent number: 5403356
    Abstract: A method and apparatus for pacing the atrium to reduce the incidence of dangerous arrhythmias. Electrodes are located at least two locations within the atrium, preferably in the triangle of Koch and/or an area of prolonged effective refractory period elsewhere within the atrium. Additional or alternative electrode locations may also be employed. The apparatus defines a variable interval following atrial depolarizations, based on the detected rate of the depolarizations. In response to a sensed depolarization at one of the locations, outside the variable interval, pacing pulses are delivered at least to the electrodes located at the other locations. Demand atrial pacing using some or all electrodes is also provided.
    Type: Grant
    Filed: April 28, 1993
    Date of Patent: April 4, 1995
    Assignee: Medtronic, Inc.
    Inventors: Michael Hill, Mehra Rahul
  • Fault-tolerant elective replacement indication for implantable medical device
    Patent number: 5402070
    Abstract: A pacemaker having a fault-tolerant elective replacement indicator (ERI) triggering scheme in which transient excursions of parameters used as criteria for triggering ERI are rejected as triggering events. Periodic assessments of certain indicia of battery depletion are made, and subjected to a long-term low-pass filtering operation in order to reduce the effects of transient excursions of the indicia which result from non-ERI conditions. Over a long period of time (e.g., a day) predetermined threshold values of the indicia of interest must be exceeded a predetermined number of times in order for the device to issue an ERI. In one disclosed embodiment of the invention, the battery's loaded terminal voltage and internal impedance are used as indicators of the battery's depletion level. Periodically, these values are measured and converted to digital values.
    Type: Grant
    Filed: July 15, 1994
    Date of Patent: March 28, 1995
    Assignee: Medtronic, Inc.
    Inventors: Michael B. Shelton, Ross O. Starkson, Craig L. Schmidt, H. Toby Markowitz
  • RF lead fixation and implantable lead
    Patent number: 5383922
    Abstract: A method and apparatus for affixing implantable catheters and leads to body tissue. An electrode located on the lead or catheter is coupled to an RF signal generator, of the type employed to perform electrosurgical procedures such as electrocoagulation. The RF signal causes the electrode to adhere to body tissue, thus stabilizing the location of the catheter or lead. The electrode may be an electrode normally employed for other purposes, such as cardiac pacing, or may be a dedicated electrode employed only for affixation. Contact between the electrode and the RF signal generator may be made by a conductor permanently mounted within the catheter or lead, or by a removable conductor.
    Type: Grant
    Filed: March 15, 1993
    Date of Patent: January 24, 1995
    Assignee: Medtronic, Inc.
    Inventors: Duglas P. Zipes, Clare P. Ulrich, Paul D. Blankenau, William M. Terrell
  • Method and apparatus for tachyarrhythmia detection and treatment
    Patent number: 5383910
    Abstract: A device for detection and treatment of tachycardias, which is able to selectively identify the occurrence of re-entrant AV nodal tachycardia, and to distinguish it from sinus tachycardias. The apparatus monitors the occurrence of atrial and ventricular depolarizations during a detected tachycardia, and, in the event that a series of ventricular depolarizations occur which are each closely preceded or closely followed by an atrial depolarization, at an interval substantially less than would be expected in the case of a sinus tachycardia, re-entrant AV nodal tachycardia is identified, and an appropriate therapy regimen is triggered.
    Type: Grant
    Filed: February 19, 1993
    Date of Patent: January 24, 1995
    Assignee: Medtronic, Inc.
    Inventor: Karel den Dulk
  • Diagnostic telemetry system for an apparatus for detection and treatment of tachycardia and fibrillation
    Patent number: 5383909
    Abstract: An implantable antitachyarrhythmia device having the capability of detecting multiple tachyarrhythmias, such as ventricular tachycardia and ventricular fibrillation and capable of delivering multiple therapies, such as antitachycardia pacing, cardioversion and defibrillation. In order to assist the physician in understanding the progress of the device toward detecting a tachyarrhythmia and to better understand the operation of the therapy provided by the device, the device transmits information related to these functions on a beat by beat basis, as a supplement to marker signals associated with paced and sensed heart events. The information telemetry regarding detection allows the physician to determine how the particular R--R interval preceding the telemetry has effected the internal counts or other diagnostic parameters required to accomplish tachyarrhythmia detection.
    Type: Grant
    Filed: January 29, 1993
    Date of Patent: January 24, 1995
    Assignee: Medtronic, Inc.
    Inventor: John G. Keimel
  • Dual chamber pacemaker system and method for delivering atrial sync pulses
    Patent number: 5374280
    Abstract: A dual chamber pacemaker is provided, preferably either DDDR or DDIR, having logic hardware and/or software for normally carrying out the DDIR or DDDR mode of operation, and further having means for avoiding delivery of an atrial pace pulse in circumstances where normal atrial pacing could otherwise be competitive or result in loss of atrial capture. The pacemaker has means for detecting an atrial sense during PVARP, timing out a delay from the time of the early atrial sense, and inhibiting delivery of an atrial pulse during the delay. In a preferred embodiment, the ventricular rate, which may be established by a rate responsive sensor, is maintained, while atrial sync pulses are delivered whenever possible following an early atrial sense so as to provide synchronous pacing whenever that is consistent with safe atrial pacing and substantial regularity of the ventricular pacing.
    Type: Grant
    Filed: January 6, 1994
    Date of Patent: December 20, 1994
    Assignee: Medtronic, Inc.
    Inventor: Karel den Dulk
  • Switchable connector block for implantable defibrillator
    Patent number: 5374279
    Abstract: A medical electrical pulse generator having a switchable connector assembly. The connector assembly is provided with connector bores, each intended to receive a medical electrical lead or a sealing plug, if no lead is provided. Electrical connectors located within the bores are arranged such that interconnection of the pulse generator circuitry within the device and electrodes on the leads and/or housing of the device can be altered by means of connector pins located on the electrical leads or the sealing plugs, which may be employed to interconnect electrical connectors within a connector bore.
    Type: Grant
    Filed: October 30, 1992
    Date of Patent: December 20, 1994
    Assignee: Medtronic, Inc.
    Inventors: Edwin G. Duffin, Jr., Warren S. Watson, Karel F. A. A. Smits
  • Medical stimulator with multiple operational amplifier output stimulation circuits
    Patent number: 5370665
    Abstract: A cardiac pacemaker or other tissue stimulator including first and second stimulation electrodes mounted adjacent to one another and adjacent the tissue to be stimulated, such as a chamber of a heart, a return electrode and a pulse generator which independently generates two or more stimulation pulses. The pulses are applied between the first stimulation electrode and the return electrode and between the second electrode and the return electrode in an overlapping fashion. By controlling the relative timing and polarity of the pulses, the potential gradient between the electrodes and the rate of change of the potential gradient may be varied.
    Type: Grant
    Filed: February 19, 1993
    Date of Patent: December 6, 1994
    Assignee: Medtronic, Inc.
    Inventor: Terrence R. Hudrlik
  • Method and apparatus for implantation of defibrillation electrodes system
    Patent number: 5366494
    Abstract: A method and apparatus for implantation of an electrode system. The apparatus includes a pacing lead and an extender, both of which are provided with internal stylet lumens. When coupled to one another, the stylet lumen of the extender is in communication with the stylet lumen of the lead, allowing passage of a stylet through both lead and extender, while coupled together.
    Type: Grant
    Filed: April 30, 1993
    Date of Patent: November 22, 1994
    Assignee: Medtronic, Inc.
    Inventors: Timothy W. Holleman, Clare P. Ulrich, Brian L. Fideler
  • Multiple pulse cardioversion or defibrillation
    Patent number: 5360435
    Abstract: A cardioverter or defibrillator employing multiple electrode pairs. The device includes an output stage comprising two capacitors or capacitor banks which are connected in parallel during the discharge of the first pulse between the electrodes in one pair and are thereafter connected in series and discharged between the electrodes in a second electrode pair.
    Type: Grant
    Filed: February 19, 1993
    Date of Patent: November 1, 1994
    Assignee: Medtronic, Inc.
    Inventor: Paul DeGroot