Intermedics Inc.

Sulzer Intermedics, Inc.

Other

Lawrence J Stotts

Eckhard U Alt

David Prutchi

Patrick J Paul

D Curtis Deno

Edward A Schroeppel

Richard S Sanders

Joseph W Vandegriff

John P Rosborough

Matthias Schmidt

Benjamin D Pless

Drury L Woodson

James P Nelson

John Garcia

Michael Lee

Device and method are disclosed in which leads with pacing and defibrillating electrodes are implanted into both the right and left ventricles of a patient's heart to enable simultaneous pacing of both ventricles to reduce the width of the QRS complex of the patient's cardiac activity to a more normal duration, and, when appropriate, to apply electrical shock waveforms to both ventricles simultaneously for lower energy defibrillation of the ventricles. In applying the defibrillation therapy, the defibrillating electrode in the left ventricle may be used as the anode and the defibrillating electrode in the right ventricle may be used as the cathode, or both ventricular defibrillating electrodes may be the anode and the metal case in which the shock waveform generator is implanted may be the cathode. Implanting a lead with pacing and defibrillating electrodes in the right atrium enables selective pacing and defibrillation of the atria, in which atrial fibrillation is treated by applying the shock waveform across the right atrial and left ventricular defibrillation electrodes.

Method and apparatus for dual chamber bi-ventricular pacing and defibrillation

An apparatus and method for treating post-defibrillation electromechanical dissociation (&ldquo;EMD&rdquo;) or pulseless electrical activity (&ldquo;PEA&rdquo;). A first embodiment comprises an implantable defibrillator with the capability of detecting and treating post defibrillation EMD. The stimulator/defibrillator has one or more leads with electrodes and at least one electrode for defibrillation. A sense circuit senses the electrical condition of the heart of the patient. A second sensor senses a parameter correlated to the state of blood flow. The cardiac stimulator/defibrillator detects and terminates ventricular tachyarrhythmia or fibrillation. If the stimulator/defibrillator detects the presence of electrical rhythm in the heart correlated, however, with inadequate blood flow to sustain life (EMD), the device provides an output to stimulate the heart to overcome EMD. The device may also be an external defibrillator. The method for treating the heart to restore blood flow where electromechanical dissociation occurs after termination of a ventricular tachyarrhythmia or ventricular fibrillation comprises identifying electromechanical disassociation after termination of a ventricular tachyarrhythmia or a fibrillation and inducing or re-inducing ventricular fibrillation and subsequently applying defibrillating shocks to terminate the fibrillation.

Method and apparatus for treatment of cardiac electromechanical dissociation

An implantable medical interventional device responds to detection of any of a plurality of cardiac dysrhythmias in a human patient by performing an appropriate therapy which may include cardiac pacing, cardioversion or defibrillation according to the nature of the detected dysrhythmia. A first sensor detects whether and what type of dysrhythmia is occurring. A generator produces pulses and/or shocks for delivery to the patient's heart according to whether a detected dysrhythmia is bradycardia or slow pathologic tachycardia on the one hand, or fast tachycardia or fibrillation on the other hand. An optimizer in the device at all times maintains a substantial match of the cardiac pacing rate to the hemodynamic needs of the implant patient under conditions of rest and physical activity; including sensing and distinguishing periods of patient physical activity and rest, and generating a signal representative thereof to control the cardiac pacing rate accordingly. In this way, the device focuses on correction of cardiac pacing problems before they become sufficiently aggravated to require more aggressive cardioversion and defibrillation therapies.

Defibrillator with improved hemodynamic response and enhanced myocardial

An interventional medical device has a capability to sense cardiac dysrhythmias and to selectively respond with one among a hierarchy of therapies appropriate to terminate the sensed dysrhythmia and return the heart of the patient in whom the device is adapted to be implanted to normal sinus rhythm. The device includes a therapy generator having a housing and electronics for conducting bidirectional communication with the patient. The bidirectional communication is carried out by detecting the occurrence of a predetermined dysrhytlnia, such as atrial fibrillation, to alert the patient of such occurrence, and by responding to instructions from the patient following such alert for addressing the detected predetermined dysrhythmia. The detection is performed by electrodes mounted directly on the header of the device housing to both detect occurrence of the atrial fibrillation and for alerting the patient thereof by stimulating body tissue such as pectoral muscle in the vicinity of the header electrodes. Response to patient-initiated instructions is implemented by triggering certain device functions such as storage of ECG events detected by the header electrodes, or deliver of a therapy appropriate to terminate the atrial defibrillation, or delay of delivery of the appropriate therapy, according to the nature of the patient-initiated instructions.

Cardiac pacemaker with bidirectional communication

An implantable cardiac pacemaker is adapted to be selectively non-invasively upgraded from time to time after implantation to provide a plurality of different diagnostic, functional, and pacing operational modes in the form of respective combinations of single and dual chamber sensing and pacing and rate-adaptive pacing of a patient's heart to correct any of various cardiac arrhythmias attributable to cardiac pacing or cardiovascular disorders, and of extended memory and physiological monitoring functions. The pacemaker is implemented to make available the plurality of different pacing operational and other functional modes, and is programmable to selectively enable current operation of at least one of the available pacing operational modes according to current needs of the patient while inhibiting current operation of all other available pacing operational modes and any other non-selected functional modes. Subsequently, the implanted pacemaker may be programmed non-invasively to selectively restore operation of at least one of the inhibited pacing operational modes or other functional modes when the patient evidences a need therefor, but the selective restoration programming is locked out unless performed with a prescribed security access key. Additional charges are imposed on the patient or third party payor for the extended upgrade functions, but considerably less than the cost of a replacement device and a surgical implant procedure, while converting the implanted device from an initially inexpensive and basic form to a more sophisticated form tailored to appropriate treatment and monitoring of the patient's condition.

Programmably upgradable implantable cardiac pacemaker

A vascular stent adapted to be implanted in a blood vessel of a human patient to enhance the flow of blood therethrough, includes an elongate biocompatible metal member of cylindrical shape and tubular sidewall with a pattern of multiple openings therethrough and open ends. The stent has an insertion outer diameter sufficiently small to enable it to be inserted into and advanced through a portion of the vascular system of the body to a preselected point within a coronary artery. The sidewall has a thin adherent coating of iridium oxide covering substantially its entire exposed surface, including the outward-facing surface between openings, the edges of the openings, the inward-facing surface between openings, and the edge of each of the open ends. The coating is of substantially uniform thickness throughout its coverage of the surface of the sidewall, and serves to reduce irritation of tissue of the inner lining of the vessel wall into which the outward-facing surface of the stent comes into contact. The tissue may project as well into the openings in the sidewall to contact the edges thereof. The iridium oxide coating has a biodegradable carrier of drugs applied thereto for beneficial localized action, as by incorporating into the carrier along the inward-facing surface an anticoagulant drug to reduce attachment of thrombi with blood flow through the lumen of the stent. Although it may be composed of multiple layers, the iridium oxide coating is sufficiently thin and flexible to resist flaking during deployment, and the core member has sufficient rigidity when so deployed to resist collapse.

Vascular and endoluminal stents with iridium oxide coating

A defibrillator is designed for implantation in a patient and for programming certain of its parameters after implantation, including energy content of a shock waveform and timing of delivery of the shock waveform. A shock waveform generator of the device is responsive to a trigger signal for timed production of a shock waveform having a programmable shape and energy content designed for terminating atrial or ventricular fibrillation (AF or VF) of the patient. A detection circuit processes a sensed cardiac signal of the patient to determine the relative timing of various portions of the cardiac signal, including the P-wave and the T-wave. In a test mode of the device, the energy content of a shock waveform is programmed to a magnitude exceeding the upper limit of vulnerability (ULV) of the patient, and the trigger signal times the delivery of a shock waveform of proper magnitude relative to the occurrence of a selected event in the cardiac signal, such as a cardiac stimulus, the P-wave or QRS complex, for application to the patient's heart coincident with the vulnerable period of a P-wave or a T-wave. In a method for testing the capability of the defibrillator to terminate VF, the probable ULV of the patient's heart is determined or estimated, the defibrillator is set to deliver a shock of sufficient energy to exceed the probable ULV, and delivery of the shock is initiated into the vulnerable period of the P-wave or T-wave. The defibrillator is selected with the capacity to deliver a shock of maximum energy exceeding the probable ULV by a margin deemed to provide an adequate safety margin for the patient. The occurrence of the vulnerable period of the P-wave or T-wave is precisely timed from a predetermined event in the patient's cardiac signal.

Implantable defibrillator with improved testing of capability to

A method of implanting small diameter conductive leads for an artificial cardiac pacemaker or other body-implantable medical device includes inserting the lead to be implanted into a predetermined path within the patient's body with the assistance of a stylet for guiding the lead along the path. At least a portion of the stylet which is to traverse the path has an enhanced radiopaque characteristic attributable to the application or addition to the material of which the stylet is composed, of a substance having such radiopaque characteristic. When viewed under fluoroscopy external to the patient's body as the lead is maneuvered along the path, although the thin lead itself may be difficult to see, the stylet is readily discernible by virtue of its enhanced radiopacity, thereby enabling the physician to position the lead at a desired location within the patient's body. For various reasons, the thin lead itself may not be amenable to similar enhancement, which makes the stylet a suitable solution. A portion of the distal end of the stylet, such as its distal tip or a plurality of spaced apart points along its distal end, is provided with the enhanced radiopacity, as by application or addition of gold to the stylet material.

Method for enhancing implantation of thin leads

An interventional medical device has a capability to sense cardiac dysrhythmias and to selectively respond with one among a hierarchy of therapies appropriate to terminate the sensed dysrhythmia and return the heart of the patient in whom the device is adapted to be implanted to normal sinus rhythm. The device includes a therapy generator having a housing and electronics for conducting bidirectional communication with the patient. The bidirectional communication is carried out by detecting the occurrence of a predetermined dysrhythmia, such as atrial fibrillation, to alert the patient of such occurrence, and by responding to instructions from the patient following such alert for addressing the detected predetermined dysrhythmia. The detection is performed by electrodes mounted directly on the header of the device housing to both detect occurrence of the atrial fibrillation and for alerting the patient thereof by stimulating body tissue such as pectoral muscle in the vicinity of the header electrodes. Response to patient-initiated instructions is implemented by triggering certain device functions such as storage of ECG events detected by the header electrodes, or deliver of a therapy appropriate to terminate the atrial defibrillation, or delay of delivery of the appropriate therapy, according to the nature of the patient-initiated instructions.

An implantable, rate responsive pacemaker, sensitive to impedance changes in the heart, wherein the cardiac pacing rate and maximum cardiac pacing rate, or either of them, are adjusted as a function of an interval between either the administration of a pacing pulse or the detection of the R-wave and the occurrence of a maximum detected impedance, called the intercept interval. Because an intercept point in derivative of the impedance curve is detected, the apparatus and method are insensitive to electrode characteristics, electrode movement, body posture or other factors which could affect the magnitude of the detected impedance. The information contained in the intercept interval can also be combined with other sensed or calculated information to set the desired rates.

Rate responsive cardiac pacemaker with peak impedance detection for rate

An implantable cardioverter/defibrillator device is implemented to be selectively non-invasively upgraded from time to time after implantation to enable the device to provide additional therapy for arrhythmia treatment as the patient's need for such treatment undergoes change. The device is adapted to provide a plurality of functions corresponding to different levels of therapy for treating arrhythmias, and to respond to each different type of arrhythmia that may be sensed, to supply a function which is designated as being appropriate to relieve that respective arrhythmia. Each function is not necessarily unique to treating a particular arrhythmia, and, in at least some instances, may be used to treat more than one of the plurality of different types of arrhythmias. At the time of its implant, the device is restricted from providing those of the plurality of functions which are deemed as being non-essential to the patient's needs at that time. From time to time thereafter, however, as the patient experiences periodic need for additional therapy, restricted functions of the device are selectively restored by external programming, but only if the programmer is able to supply to the device an enabling code which is substantially unique to that device. In this way, restoration of the restricted functions is locked out except with a prescribed key.

Programmably upgradable implantable medical device

A variable rate cardiac pacemaker is adapted to be implanted in a human patient for automatically adapting pacing rate to metabolic need of the patient when the patient is walking in an ascending path, a descending path, or on a level plane. An accelerometer senses the activity of the patient walking, and produces an electrical sensor signal representative of the activity. The accelerometer signal has variable parameters indicative of morphology, including amplitude, of the sensor signal according to status of activity of the patient and to the upward, downward, or horizontal direction of the patient's walking. A pulse generator generates pacing pulses at a variable rate according to an applied control signal to electrically stimulate the patient's heart at a pacing rate which varies according to patient activity. A processing and control circuit of the pacemaker processes the sensor signal for detecting differences in the signal morphology attributable to whether the patient is walking on an ascending path, a descending path, or a level path, irrespective of the presence or absence of disparity in the amplitude of the sensor signal resulting from walking along the respective path. The latter circuit also develops the control signal to dictate a basic pacing rate from the amplitude of the sensor signal, and an enhanced rate more appropriate to the metabolic need of the patient from the detected differences in morphology of the sensor signal, for application to the pulse generator.

Accelerometer-based rate-adaptive cardiac pacing with second generation

A cardiac simulation system with a patient warning apparatus, including a pin electrode insertable into a standard female socket in the header of a dual chamber pacer or multi-function cardiac stimulator. The cardiac stimulator has at least two sockets in a header, such as is commonly found in a dual chamber pacemaker. Rather than stimulating both chambers of the heart, the dual chamber pacemaker is programmed to function as a single chamber pacemaker, with a standard lead connecting one socket and its associated circuitry to a selected chamber of the heart, usually the ventricle. The pin electrode is inserted in the other socket, usually used for the sensing and stimulation of the atrium, and additional programming is provided to the pacemaker or stimulator to automatically produce an output stimulus through the atrial socket to the pin electrode whenever a condition exists requiring patient notification or warning. The pin electrode includes a hood which fits around a selected part of a header. The hood has edges or corners which are electrically conductive, but the largest portion of the hood is electrically non-conductive.

Muscle stimulation electrode for implantable cardiac stimulation device

A programmable dual-chamber artificial cardiac pacemaker senses atrial activity and normally tracks the sensed atrial activity in pacing the ventricular activity. An accelerometer located in the case of the pulse generator portion senses physical exercise by a patient when the pacemaker is implanted in the patient, and generates a rate control signal indicative of extent of the sensed physical exercise. The pulse generator is programmed for ventricular pacing rate control in multiple rate zones bounded by rate limits including a ventricular tracking limit (VTL) that varies dynamically with sensed physical exercise and a higher mode switch rate. The ventricular pacing rate tracks the sensed atrial activity on a 1:1 basis for atrial rates below the dynamic VTL (DVTL) during a predetermined interval of time for which the DVTL applies, and tracks the sensed atrial activity in Wenckebach behavior for atrial rates above the DVTL up to the mode switch rate with the ventricular pacing rate limited by the DVTL. The mode switch rate is set to effect a switch from dual-chamber to single-chamber mode when the sensed rate of atrial activity exceeds the mode switch rate for a programmed number of cardiac cycles, in which the ventricular pacing rate is controlled solely by sensed spontaneous ventricular activity without regard to the DVTL or sensed physical exercise. The mode switch rate also effects a reversion to the dual-chamber mode when the sensed rate of atrial activity drops below the mode switch rate for a programmed number of cardiac cycles, in which the ventricular pacing rate is controlled according to the respective one of the multiple rate zones in which the atrial activity rate is present.

Control of pacing rate in dual-chamber, rate-adaptive pacemakers

A cardiac simulator including a patient warning apparatus, having a sensor for detecting patient reaction to a warning stimulus and means for adjusting the magnitude of said warning stimulus to obtain a preselected level of reaction. The cardiac stimulator is an implantable pacemaker or defibrillator or combination which can be programmed to produce a warning stimulus whenever a condition exists requiring patient notification or warning. A warning pulse stimulus generator directs electrical current to a warning electrode. Alternatively, a controlled switch may re-direct a stimulation pulse to the warning electrode. The sensor for detecting the reaction of the patient to the applied warning stimulus may be an accelerometer or motion/vibration transducer or other sensor capable of detecting a reaction to a warning stimulus. Means for adjusting the level of the stimulus directed to the patient's skeletal muscle regulate the stimulus until a pre-selected magnitude of reaction has been achieved. The reaction is also maintained below a pre-selected maximum to avoid discomfort to the patient.

Growing community of inventors

Lake Jackson, TX, United States of America

Lawrence J Stotts