Abstract: 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.

Abstract: An apparatus and method for treating post-defibrillation electromechanical dissociation (“EMD”) or pulseless electrical activity (“PEA”). 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A defibrillator has a signal generator implemented to deliver output shock waveforms and housed in a case adapted to be implanted in the left pectoral region of a cardiac patient. The case is implemented to interact with internal circuitry of the generator to maintain the case active as an electrode. An electrical transvenous lead has a proximal electrode for electrical connection to the internal circuitry of the signal generator and a distal end adapted to be positioned in the right ventricle (RV) of the patient's heart. The lead includes a sensing tip for contacting the RV to sense the patient's ECG signal and a shocking coil arranged to be located in the RV when the transvenous lead is implanted in the patient. The internal circuitry of the signal generator includes triggerable output circuit for developing an output shock waveform when triggered in response to detection of ventricular fibrillation of the patient's heart from the sensed ECG signal.

Abstract: 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. Our invention includes a specialized pin electrode with an orifice for a suture.

Abstract: An implantable automatic cardioverter/defibrillator device for a cardiac patient is automatically responsive to sensing of electrical cardiac activity of the heart of a patient in which the device is implanted for detection and treatment of fibrillation. A prescribed electrical shock waveform regimen is generated as electrical defibrillation therapy for application to the heart in response to detection of fibrillation of the heart. A timing function circuit responds to the detection by timing the delivery of the generated prescribed electrical waveform regimen to be applied at a point in time at which the fibrillation ECG has substantially its highest amplitude and lowest frequency, as a point of high susceptibility to reversion to sinus rhythm upon application of a shock, and with low defibfillation threshold, to enhance the probability of successful defibrillation, and to synchronize the shock delivery to this sensed intracardiac event.

Abstract: An automatic defibrillator is arranged and adapted to be implanted in a cardiac patient. The defibrillator includes a stimulus generator for sensing fibrillation of the patient's heart and for responding by delivering defibrillation energy to the patient's heart via a defibrillation electrode positioned in the right ventricle of the heart. An electrically conductive case houses the stimulus generator, and a conforming biocompatible electrically non-conductive layer is coated over only a predetermined portion less than all of the case to produce a predetermined shape of electric field between the intracardiac defibrillation electrode and the case when the case is used as an electrode for defibrillation. The predetermined portion of the case coated with the non-conductive layer includes a side of the case to be implanted in a direction facing the heart of the patient, with the non-conductive layer being confined solely to the central portion of that side.

Abstract: A pulse generator for a cardiac pacemaker is adapted to be implanted beneath the skin and adjacent the musculus with either of its two sides facing the musculus and its other side facing outwardly of the patient's body, at the option of the implanting surgeon, according to the desired orientation of the receptacle of the header for connection of an electrode lead to the pulse generator, and at the same time avoiding the presence of spurious signals attributable to flexation of the adjacent musculus and twitching attributable to stimulation of the adjacent musculus during operation of the pulse generator when implanted. To that end, the entire surface of the case is coated with an electrically insulative, biocompatible film except along a portion of the edge of the case between its two major sides which is to serve as an anodal contact surface for stimulating and sensing cardiac activity of the patient.