Abstract: A single pass lead system for defibrillating the heart is shown. Portion of the lead is relatively stiff and holds the lead in the SVC. This stiff section extends into the atrium where good contact with the electrodes on the lead are maintained by the lead stiffness. A very flexible distal portion carries defibrillation leads into the ventricle.

Abstract: The present invention provides an improved extracardiac indifferent electrode configuration for implantable medical devices that overcomes the deficiencies of known unipolar and bipolar cardiac sensing and pacing systems. In particular, the present invention provides an indifferent electrode configuration wherein a subcutaneous extracardiac electrode is advantageously positioned so as to provide a truly indifferent return or reference electrode that does not inadvertently stimulate torso muscle and is not subject to detecting myopotentials generated by adjacent torso muscle. In addition, by being placed outside the heart, the indifferent electrode allows the intracardiac catheter to maintain a low profile, i.e., allows the catheter to be as small as possible, and does not generate metallic ions or cause degradation of catheter materials by generating such ions.

Abstract: A single preformed catheter configuration for a dual-chamber pacemaker system is provided. The catheter is formed of a heat-settable biocompatible material such as, for example, polyether polyurethane, and is formed in a predetermined shape to enhance and stabilize atrial electrode contact on the inner wall of the atrium, while also providing stress relief to absorb stresses occasioned by cardiac depolarization and respiration and modulation of the bulk cardiac complex. To this end, the catheter of the present invention includes a first section disposed in the superior vena cava to provide substantially stable support to the catheter, a second section disposed in the atrium and being preformed to substantially conform to the inner wall of the atrium, and a third section having a pliancy greater than that of the first two sections and being disposed distally of the second section.

Abstract: An electronic device for non-invasively communicating with an implanted device, such as, for example, a cardiac pacemaker. The electronic programming device includes a transceiver having an antenna, a transmitter portion and a receiver portion. The antenna portion is arranged to have two coils arranged in series phase opposition to suppress the effects of far-field interference signals on received near-field signals from the implanted device, when the transceiver is receiving data from the implanted device. The electronic device further includes means to isolate the transmit and receive functions thereof to prevent cancellation of the transmitted signal when the transceiver is in the transmit mode.

Abstract: A catheter lead for a cardiac pacemaker in which stimulating pulses are generated for delivery to the heart according to physiological need of the patient determined by signals obtained solely from the detection of naturally occurring P-waves propagating through the atrial myocardial tissue.

Abstract: An optimum placement, shape and orientation of catheter electrodes in a cardiac pacemaker system takes advantage of the peak-positive to peak-negative summative effect of a diphasic depolarization wave front of the P wave necessary to the beating of a heart. Electrode surface areas are maintained in the 4 to 6 mm.sup.2 range and disposed so as to minimize signal attenuation from gradient averaging of the depolarizing signature and also to minimize the effect of uncontrollable angular rotation of the cathether.

Abstract: A heart pacing and monitoring system includes a new lead system which, when used in conjunction with a telemetry-pacemaker system, permits the transmission of the complete intracardiac electrogram and is not adversely affected by pacemaker outputs or after potentials. Detecting ring electrodes are placed in both right atrium and ventricle in order to optimize electrogram (EGM) detection. Electrically separate from the pacing-sensing electrodes, the detecting electrodes are structurally part of a transvenously placed ventricular lead no larger than a conventional bipolar lead. The EGM telemetry system is also compatible with telephone monitoring systems. The present system is operative to detect and telemetrically record the entire normal and abnormal electrogram even in pacer dependent patients.

Abstract: A system for internally sensing the cardiac electrogram in a patient with a cardiac pacemaker is disclosed comprising an implanted electrode that, in combination with the metallic case of the pacemaker which acts as an indifferent electrode, senses cardiac electrical signals and provides them as an input to the pacer electronics. The sensing electrode is appropriately spaced from the pacing electrode and positioned so that cross coupling is minimized to permit sensing of the cardiac electrogram without undue interference from the pacing stimulus and after potentials, and so that the pickup of both R- and P-waves is optimized. The sensed signals may be used to control atrial, ventricular or multichamber demand pacemakers and/or may be telemetered out of the patient for pickup and analysis by external equipment. A flat plate and a preferred cylindrical ring form of electrode are described.

Abstract: A complete system for telemetering and monitoring the functioning of an implanted pacemaker as well as controlling the testing of the functions from a remotely located central facility is disclosed specifically comprising the provision of capabilities for directly and simultaneously transmitting from the pacer, electrical signals indicative of multiple pacer functions such as pacer rate, cell voltage, refractory period, heart rate with pacer inhibited, R-wave level and sensing margin, sensing circuit and other component failure, cardiac electrode, lead break, and hermetic integrity. The indicative signals are picked up at the patient's location for local analysis and/or telephonically communicated to a remote central monitoring station. The central station may control testing of the pacemaker functions by transmitting command signals back telephonically for coupling through cooperating external and implanted inductances or mangetically controlled switches to the implanted pacer circuitry.

Abstract: A complete system for telemetering and monitoring the functioning of an implanted pacemaker as well as controlling the testing of the functions from a remotely located central facility is disclosed specifically comprising the provision of capabilities for directly and simultaneously transmitting from the pacer, electrical signals indicative of multiple pacer functions, such as, pacer rate, cell voltage, refractory period, heart rate with pacer inhibited, R-wave level and sensing margin, sensing circuit and other component failure, cardiac electrode lead break, and hermetic integrity. The indicative signals are picked up at the patient's location for local analysis and/or telephonically communicated to a remote central monitoring station. The central station may control testing of the pacemaker functions by transmitting command signals back telephonically for coupling through cooperating external and implanted inductances or magnetically controlled switches to the implanted pacer circuitry.

Abstract: A system for extending the lifetime of an implantable cardiac pacer of the type having an internal primary battery power source includes an external energy transmitting source for selectively externally powering the pacer in order to reduce consumption of the internal battery power. While the pacer is operating on external power, current drain from the internal primary battery is reduced substantially to zero, thus extending useful battery life. The external energy source may include an electromagnetic energy transmitting coil, which transmits energy to an implanted energy receiving coil, the received energy being then rectified, filtered, and used to power the pacer. If a large-diameter energy transmitting coil is employed, the transmitting and receiving coils may be loosely coupled to provide a more convenient and easy-to-use energy conservation system.

Abstract: A cardiac pacing apparatus of the type having a first signal processing channel which functions in the demand mode is disclosed including a second signal processing channel for detecting electromagnetic interference and causing the pacing apparatus to revert to a safe operating rate in the presence of such interference. In a preferred embodiment, the second signal processing channel has an enhanced high-frequency response with respect to that of the first signal processing channel in order to optimize interference detection. The second channel may receive an input from either a conventional cardiac sensing and pacing electrode, or else a second electrode, remote from the heart, may be provided for interference detection.

Abstract: A system for telemetering the performance of an implanted cardiac pacer incorporating a low power, low voltage, frequency-voltage sensitive pulse generator which supplies a pulse-interval-modulated telemetry output and includes an astable complementary multivibrator in combination with a voltage clipping feedback network.

Abstract: An hermetically-sealed cardiac pacemaker which may be operated on a single non-rechargeable cell or a magnetic-induction-rechargeable mercury cell that is hermetically sealed along with an outgas alleviating material in a separate container within an integral stainless steel outer case, which case also houses the system electronics. The integral case is formed with an opening in which a closure plate is disposed in a recessed position and sealed about its periphery to the interior of the opening to form a receptacle in the exterior of the casing. The receptacle is filled with a biocompatible material to isolate the seal from the exterior of the casing and the case acts along with the internal electronics during recharging as a charging current regulator system which maintains a substantially constant power transfer from the charging transmitter to the internal receiver despite variations in their proximate spacing.

Abstract: A cardiac pacer system includes a first relatively large contact area electrode for sensing cardiac activity and a second electrode of substantially smaller contact area than the first to apply artificial stimulating pulses to the heart. The first electrode has a sufficiently large contact area to achieve a relatively high sensitivity to cardiac activity and the second electrode has a sufficiently small contact area to generate a relatively high current density at the electrode-tissue interface when the artificial stimulating pulses are applied to the heart. The electrodes are supported in a spaced relationship by an electrically insulating spacer. Each electrode may be directly wired to an appropriate point within the cardiac pacer, and referenced to a common electrical return point by means of a third, common electrode. Alternatively, the first and second electrodes may be connected to the pacer with a single lead, with suitable decoupling circuitry between the single lead and each electrode.

Abstract: A low current, low voltage impulse generating system for cardiac pacers using a complementary multivibrator in combination with an RC network which operates in an astable, supply voltage insensitive mode to produce fixed rate pacing pulses.

Abstract: A cardiac pacing apparatus includes a trigger pulse generator which generates trigger pulses at a predetermined minimum rate when the natural heart rate fails to exceed the predetermined minimum rate and which follows the natural heart rate when the heart rate is above the predetermined rate, an output pulse generator for generating artificial heart stimulating pulses, a timing interval generator for generating a fixed timing interval in response to the generation of each artificial heart stimulating pulse, and an inhibit gate for selectively applying only those trigger pulses which occur outside the fixed timing intervals to the output pulse generator. The output pulse generator is maximum-rate limited as an inverse function of the fixed timing interval duration regardless of the input rate, and pulses at the minimum predetermined rate, as established by the trigger pulse generator, are generated after an escapement interval in the absence of natural cardiac activity.