Abstract: A neural stimulus comprises at least three stimulus components, each comprising at least one of a temporal stimulus phase and a spatial stimulus pole. A first stimulus component delivers a first charge which is unequal to a third charge delivered by a third stimulus component, and the first charge and third charge are selected so as to give rise to reduced artefact at recording electrodes. In turn this may be exploited to independently control a correlation delay of a vector detector and an artefact vector to be non-parallel or orthogonal.

Abstract: A subcutaneously implantable device includes a clip that is configured to anchor the subcutaneously implantable device to a muscle, a bone, and/or a first tissue, and a first prong with a proximal end secured adjacent to the clip and a distal end extending away from the clip that is configured to contact an organ, a nerve, and/or a second tissue. A first electrode on the first prong is configured to contact the organ, the nerve, and/or the second tissue. A cable is conductively coupled to the first electrode, wherein the cable is configured to be connected to a remote device to electrically couple the subcutaneously implanted device to the remote device.

Abstract: Devices and methods provide for the sensing of physiological signals during stimulation therapy by preventing stimulation waveform artifacts from being passed through to the amplification of the sensed physiological signal. Thus, the amplifiers are not adversely affected by the stimulation waveform and can provide for successful sensing of physiological signals between stimulation waveform pulses. A blanking switch may be used to blank the stimulation waveform artifacts where the blanking switch is operated in a manner synchronized with the stimulation waveform so that conduction in the sensing path is blocked during the stimulation pulse as well as during other troublesome artifacts such as a peak of a recharge pulse. A limiter may be used to limit the amplitude of the sensed signal, and hence the stimulation artifacts, that are passed to the amplifier without any synchronization of the limiter to the stimulation waveform.

Abstract: Passive tissue biasing circuitry in an Implantable Pulse Generator (IPG) is disclosed to facilitate the sensing of neural responses by holding the voltage of the tissue to a common mode voltage (Vcm). The IPG's conductive case electrode, or any other electrode, is passively biased to Vcm using a capacitor, as opposed to actively driving the (case) electrode to a prescribed voltage using a voltage source. Once Vcm is established, voltages accompanying the production of stimulation pulses will be referenced to Vcm, which eases neural response sensing. An amplifier can be used to set a virtual reference voltage and to limit the amount of current that flows to the case during the production of Vcm. In other examples, circuitry can be used to monitor the virtual reference voltage as useful to enabling the sensing the neural responses, and as useful to setting a compliance voltage for the current generation circuitry.

Abstract: This disclosure relates to an active medical device which includes a generator for producing multiphase nerve stimulation pulse trains, each pulse train including at least one stimulation pulse preceded by a precharge pulse and ending with a passive discharge pulse. The active medical device also includes a sensor configured to output a control signal representative of a physiological and/or physical parameter capable of being influenced by the output of nerve stimulation pulse trains. The active medical device also includes an automatic charge compensation control circuit configured to receive at the input the control signal output by the sensor, determine an amplitude and/or a precharge pulse time as a function of at least one predetermined criterion, and output to the generator a precharge pulse control signal to be produced at the output.

Abstract: An apparatus comprises a stimulus circuit, a recharge circuit, a switch circuit, and a control circuit. The stimulus circuit provides electrical cardiac pacing stimulation to multiple combinations of a plurality of electrodes, and the electrical stimulation is selectively applied at the first electrode of the electrode combinations. The recharge circuit includes a recharge capacitor electrically coupled to the second electrode of the electrode combinations, and the switch circuit selectively enables electrode combinations for electrical coupling to the stimulus circuit and the recharge circuit. The control circuit includes a pacing activation sub-circuit that selectively initiates delivery of the electrical stimulation using multiple electrode combinations, and enables simultaneous delivery of pacing recharge energy from the recharge capacitor to the second electrode of multiple electrode combinations.

Abstract: A system includes a pulse generator including a can electrode and a lead couplable to the pulse generator, the lead including a distal coil electrode and a proximal coil electrode, wherein both of the coil electrodes are electrically uncoupled from the can electrode such that a unipolar sensing vector is provided between at least one of the coil electrodes and the can electrode.

Abstract: Systems, devices, and methods are disclosed for limiting the duration of elevated pacing rates in an implantable medical device. An illustrative device may include a housing, a plurality of electrodes connected to the housing, and a controller within the housing and connected to the electrodes. The controller may deliver pacing pulses to the electrodes at a base pacing rate, detect a measure of elevated metabolic demand which may vary over time, deliver pacing pulses at an elevated pacing rate based on the measure of elevated metabolic demand. The controller may change a heart stress tracking value (HSTV) when the pacing rate is elevated and may be changed faster during times of relatively higher elevated pacing rates than times of relatively lower elevated pacing rates. The elevated pacing rate may be reduced back toward the base pacing rate after the HSTV crossed a predetermined heart stress threshold.

Abstract: Various systems are provided for filtering EMI. In one example, a system comprises a poly-modal filter coupled to a load device, and a shield disposed between the load device and the poly-modal filter. The poly-modal filter comprises an EMI filter and a differential-common mode filter.

Abstract: In some examples, the disclosure relates to a systems, devices, and techniques for delivering electrical stimulation therapy to a patient. In one example, the disclosure relates to a method including delivering a series of pulses with alternating pulse polarities to a gastrointestinal tract of a patient. The series of pulses includes at least a first pulse of a first polarity, a second pulse of a second polarity, and a third pulse of the first polarity, where the first, second and third pulses are delivered in direct succession and in that order. The first and second pulses are separated by a first time delay and the second and third pulses are separated by a second time delay. In some examples, each of the first and second time delays depend on the frequency that the series of pulses are delivered.

Abstract: An exemplary system may include a sound processor that provides radio frequency (RF) power and a cochlear implant that operates in accordance with the RF power. The cochlear implant may include a positive current source and a negative current source that may be electrically coupled to an electrode by way of a common node. The sound processor may 1) direct the cochlear implant to concurrently enable the positive and negative current sources in order to generate a current that has a first predetermined current level and that flows though the positive and negative current sources from a positive voltage supply to a negative voltage supply without providing stimulation to the electrode in a manner perceptible to the patient, and 2) determine a power level of the RF power that is required to generate the current having the first predetermined current level. Corresponding apparatuses and methods are also described.

Abstract: A method is provided for use with a human subject. The method includes accessing a cardiac site via a vena cava of the subject, and alleviating heart failure of the subject by applying to the cardiac site, during a refractory period of the site, a refractory-period signal that affects the left ventricle of the subject's heart. Other embodiments are also described.

Abstract: Embodiments of the present invention concern the timing of sending one or more commands to control circuitry of a multi-electrode lead (MEL). In one embodiment, the one or more commands are sent to control circuitry within the MEL during a predetermined portion of a cardiac pacing cycle to avoid potential problems of prior systems that were not synchronized with the cardiac pacing cycle. In one embodiment, the one or more commands are sent when cardiac tissue is refractory from a cardiac pacing pulse, to prevent the command(s) from potentially undesirably stimulating cardiac tissue. The command sending can occur such that the one or more commands are sent between instances when sensing circuitry of the implantable cardiac stimulation device is being used to obtain one or more signals indicative of cardiac electrical activity, to prevent interference between the one or more commands with the signals indicative of cardiac electrical activity that are sensed.

Abstract: A method and system for charge imbalance compensation in a stimulating medical device is provided. The stimulating medical device includes at least one electrode contact configured for providing stimulation to a recipient. A charge imbalance compensation system in the stimulating medical device measures any residual charge remaining on the electrode contact that may result from an imbalance in the applied stimulation. If the measured residual charge exceeds a threshold, the charge imbalance compensation system causes a compensator current to be applied to reduce the residual charge. This residual charge may be measured by measuring a potential difference between the electrode contact and a reference electrode; or, by measuring a potential difference across a capacitor in-series with the electrode contact.

Abstract: The invention relates to cardiac rhythm management systems, and more particularly, to rate adaptive cardiac pacing systems and methods. In an embodiment, the invention includes a cardiac rhythm management device. The device can include a pulse generator for generating electrical pulses to be delivered to a heart at a pacing rate, a processor in communication with the pulse generator, and one or more sensors for sensing pulmonary function and cardiac function. The processor can be configured to increase the pacing rate if the pulmonary function is increasing with time and the cardiac function is not decreasing with time, maintain the pacing rate if the pulmonary function is increasing with time and the cardiac function is decreasing with time, and decrease the pacing rate if the respiratory function is decreasing with time.

Abstract: A body stimulating device operatively adapted to provide electrical stimuli within a body, the device including stimulating electrodes, stimulus generator, and electrode voltage sensors, said electrode voltage sensors operatively measuring the DC/LF voltage of the electrodes, wherein if the sensors determine that the electrode voltage for an electrode is outside a predetermined range, then a compensating current is applied to that electrode, so as to reduce the voltage.

Abstract: The invention relates to cardiac rhythm management systems, and more particularly, to rate adaptive cardiac pacing systems and methods. In an embodiment, the invention includes a method for providing rate-adaptive cardiac pacing therapy from an implantable medical device, the method including sensing a pulmonary function of a patient; determining a rate of change in the pulmonary function; sensing a cardiac function of the patient; determining a rate of change in the cardiac function; and calculating a target pacing rate based on an existing pacing rate, the rate of change in the pulmonary function, and the rate of change in the cardiac function.

Abstract: Disclosed herein are circuits and methods for a multi-electrode implantable stimulator device incorporating one decoupling capacitor in the current path established via at least one cathode electrode and at least one anode electrode. In one embodiment, the decoupling capacitor may be hard-wired to a dedicated anode on the device. The cathodes are selectively activatable via stimulation switches. In another embodiment, any of the electrodes on the devices can be selectively activatable as an anode or cathode. In this embodiment, the decoupling capacitor is placed into the current path via selectable anode and cathode stimulation switches. Regardless of the implementation, the techniques allow for the benefits of capacitive decoupling without the need to associate decoupling capacitors with every electrode on the multi-electrode device, which saves space in the body of the device.

Abstract: An external defibrillator having a battery; a capacitor electrically communicable with the battery; at least two electrodes electrically communicable with the capacitor and with the skin of a patient; a controller configured to charge the capacitor from the battery and to discharge the capacitor through the electrodes; and a support supporting the battery, capacitor, electrodes and controller in a deployment configuration, the defibrillator having a maximum weight per unit area in the deployment configuration of 0.1 lb/in2 and/or a maximum thickness of 1 inch. The support may be a waterproof housing.

Abstract: A depolarization sensing threshold can be determined using an amplitude-limited portion of a cardiac signal received using an implantable medical device. One or more cardiac depolarizations can be detected using the cardiac signal and the depolarization sensing threshold.

Abstract: A cardiac electrical stimulation system that enhances the ability of the system to automatically detect whether an electrical stimulus results in heart capture or contraction. The cardiac electrical stimulation system may be utilized, for example, as a cardiac pacer or as a cardioverter defibrillator. The cardiac electrical stimulation system includes an electrical stimulation circuit that attenuates polarization voltages or “afterpotential” which develop at the heart tissue/electrode interface following the delivery of a stimulus to the heart tissue, which thereby allows the stimulation electrodes to be utilized to sense an evoked response to the electrical stimulus. The cardiac electrical stimulation system utilizes the stimulation electrodes to sense an evoked response, thereby eliminating the necessity for an indifferent electrode to sense an evoked response.

Abstract: External pacemaker systems and methods deliver pacing waveforms that minimize hydrolysis of the electrode gel. Compensating pulses are interleaved with the pacing pulses, with a polarity and duration that balance the net charge at the electrode locations. The compensating pulses are preferably rectangular for continuous pacing, and decay individually for on-demand pacing.

Abstract: Disclosed are systems and methods which provide trial stimulators suited for use interoperatively and during patient trial. Trial stimulator embodiments provide a patient interface and/or clinician interface which appears and functions substantially the same as an interface of a pulse generator controller which will be used after a trial period. A compliance monitor feature may be provided to facilitate verifying the proper use of the trial stimulator during a trial period. A diagnostic feature may be provided to facilitate verifying proper operation of various aspects of a trial stimulator, such as electrode impedance analysis. Trial stimulators of embodiments provide stimulation to a plurality of tissues and/or areas of the body, such as spinal cord stimulation, deep brain stimulation, etcetera. Embodiments provide for multi-electrode stimulation and multi-stimulation programs.

Abstract: A cardiac electrical stimulation system that enhances the ability of the system to automatically detect whether an electrical stimulus results in heart capture or contraction. The cardiac electrical stimulation system may be utilized, for example, as a cardiac pacer or as a cardioverter defibrillator. The cardiac electrical stimulation system includes an electrical stimulation circuit that attenuates polarization voltages or “afterpotential” which develop at the heart tissue/electrode interface following the delivery of a stimulus to the heart tissue, which thereby allows the stimulation electrodes to be utilized to sense an evoked response to the electrical stimulus. The cardiac electrical stimulation system utilizes the stimulation electrodes to sense an evoked response, thereby eliminating the necessity for an indifferent electrode to sense an evoked response.

Abstract: An implantable medical device includes two or more pacing output channels coupled to a single unipolar electrode or bipolar electrode pair. The implantable medical device can control each pacing output channel to deliver pacing pulses via the single electrode or electrode pair at different times and with different amplitudes. In some embodiments, the implantable medical device is used to deliver extra-systolic stimulation therapy. In such embodiments, a first pacing output channel can be controlled to deliver pacing pulses via the electrode or electrode pair with an amplitude sufficient to depolarize a chamber of the heart. A second pacing output channel is controlled to deliver extra-systolic pulses, which can have a lower amplitude than the pacing pulses, via the electrode or electrode pair an extra-systolic interval after sensed or paced depolarizations of the chamber. In some embodiments, the implantable medical device delivers ESS therapy and cardiac resynchronization therapy (CRT).

Abstract: The present invention provides systems, methods and computer program products for detecting the presence of cardiac activity in a patient. The present invention includes a detector circuit that is configured to detect the influence of a first defibrillation shock on the patient immediately subsequent to termination of a first defibrillation shock.

Abstract: A cardiac pacing system that enhances the ability of a cardiac pacer to automatically detect whether a pacing stimulus results in heart capture or contraction. The cardiac pacing system includes a pacing circuit that attenuates polarization voltages or “afterpotential” which develop at the heart tissue/electrode interface following the delivery of a stimulus to the heart tissue, which thereby allows the pacing electrodes to be utilized to sense an evoked response to the pacing stimulus. The cardiac pacing system utilizes the pacing electrodes to sense an evoked response, thereby eliminating the necessity for an indifferent electrode to sense an evoked response. The present invention allows accurate detection of an evoked response of the heart, to thereby determine whether each pacing stimulus results in capture.

Abstract: A heart stimulator has a stimulation energy delivering assembly, including at least one lead adapted for implantation in contact with cardiac tissue, and an atrial arrhythmia detector, and a control unit connected to the stimulation energy delivering assembly and to the detector. The control unit controls the stimulation energy delivering assembly to deliver at least one atrial arrhythmia abolishing therapy and, if continued atrial arrhythmia is detected, to deliver antithrombus stimulation energy pulses of lower energy than a defibrillation shock, but with different timing and with sufficient energy for producing atrial contraction for increasing hemodynamic blood transportation away from the atrium and for preventing thrombi formation in the atrium. For a patient suffering from a chronic or paroxysmal non-curable atrial arrhythmia, the control unit controls the stimulation energy delivering assembly to deliver the antithrombus energy without any preceding arrhythmia abolishing therapy.

Abstract: An implantable cardiac rhythm management device capable of automatically detecting intrinsic and evoked response of a patient's heart and suitable for use during capture verification. The device of the present invention may operate in an automatic capture verification mode, wherein an electrocardiogram signal of a patient's heart is received and used by the device to determine whether a stimulation pulse evokes a response by the patient's heart. The device suspends the automatic capture verification mode and/or adjust the detection threshold dependent upon detected and/or measured noise, a determined amplitude of evoked response, a determined modulation in the evoked response, or detected and/or measured artifact. Further, the sensing circuit of the rhythm management device of the present invention reduces afterpotentials that result due to delivery of the stimulation pulses.

Abstract: An active implantable medical device with a sophisticated management of the refractory periods. Such devices typically include a detection circuit and a stimulation circuit and a circuit which applies a refractory period to the detection circuit, including an absolute refractory period (ARP), which can be fixed or pre-programmed, and a relative refractory period (RRP), which is variable. The relative refractory period includes a succession of elementary periods (X) of a fixed or programmable duration, which elementary period is further subdivided into sub-periods (Y) such that an elementary period X is retriggered or restarted at the end of a sub-period Y if a residual potential of a level higher than a given threshold is detected at output of the detection circuit during that sub-period. In the absence of a detected residual potential being detected during the successive sub-periods comprising the elementary period, then the refractory period ends.

Abstract: Multi-chamber cardiac pacing systems for providing multi-site pacing to at least one of the right and left atria and then synchronously to the right and left ventricles in a triggered pacing sequence while providing for recharge of the output capacitors of each output amplifier in the shortest time. The recharge operations of the present invention come into play when bi-chamber pacing is invoked to deliver right and left heart chamber pacing pulses that are separated by a triggered pacing delay that overlaps, i.e., is shorter than, the recharge time period. In a truncated recharge mode, the first pacing pulse is delivered through the first pacing path, and the recharging of the first pacing path is commenced for the duration of the triggered pacing delay. Then, the second pacing pulse is delivered, and the second pacing path is recharged for a second recharge period. The recharging of the first pacing path is conducted simultaneously with or after completion of the second recharge period.

Abstract: A system for defibrillating an atrial region of a heart experiencing a supraventricular arrhythmia. The defibrillation system senses and analyzes both atrial and ventricular cardiac signals of the heart to determine if the heart is experiencing a supraventricular arrhythmia. Upon detecting a supraventricular arrhythmia, the defibrillation system begins delivering a train of atrial pacing pulses to the atria of the heart and a series of ventricular pacing pulses to the ventricles of the heart to synchronize the contractions of the heart with the pacing pulses. The defibrillation system then delivers a defibrillation electrical energy pulse across the atrial region at a predetermined coupling interval time after delivering a final atrial pacing pulse and a final ventricular pacing pulse so that the defibrillation pulse will fall outside the occurrence of a T-wave of the heart, thus reducing the likelihood of inducing ventricular fibrillation.

Abstract: A system and method for heating cells surrounding metallic implants in living beings. The system includes a metallic implant within the living being, surrounded by the cells to be heated, an induction coil having an aperture sufficiently large to accommodate a portion of the living being containing the metallic implant, and an RF generator coupled to the coil to apply an electric RF signal thereto, the RF signal ranging in frequency from 10 kilohertz to 10 megahertz. The metallic implant is inductively heatable by the application of the RF signal to the induction coil.

Abstract: There is provided a pacemaker system with capture verification and threshold testing, in which the pacemaker adjusts the post-stim pulse portion of a triphasic pulse to minimize polarization, and waits after each change in delivered pace pulses for a stabilization interval, in order to enhance capture verification. The threshold test utilizes a pace pulse pair, comprising a prior search pulse which is varied during the test, and the regular pacing pulse which is above threshold. When delivery of the pulse pairs is initiated, the search pulse is adjusted to optimize polarization, and the pacemaker waits for a predetermined stabilization period of time in order to allow for minimum polarization and to optimize capture detection. The search pulse is increased incrementally in output value toward threshold, and following each such increase the pacemaker waits for a stabilization interval. The pacemaker detects when capture is achieved by the search pulse, thereby providing an indication of threshold.

Abstract: A method and apparatus for attenuating polarization voltages or "afterpotentials" which develop at the heart tissue/electrode interface following the delivery of a pacing stimulus to the heart tissue such that the evoked response of the heart may be accurately detected to determine whether each pacing stimulus resulted in heart capture or contraction, thereby facilitating improved tracking of the capture threshold and minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor used to suppress DC components of the pacing spike has another, much lower capacitance capacitor connected in series with it. The lower capacitance capacitor may be operable in either the autothreshold mode or in the normal pacing mode such that its value can be selectively inserted in series with the larger capacitance coupling capacitor to effectively lower the overall capacitance of the coupling capacitor following delivery of the pacing stimulus.

Abstract: A cardiac rhythm management system provides a nonlinear gain characteristic. The system operates without blanking switches that decouple its inputs from electrodes during delivery of a pacing or recharge pulse. The nonlinear gain characteristic includes piecewise linear and logarithmic gain characteristics. Signals having amplitudes that are smaller than an input threshold voltage are amplified by less than signals having amplitudes that exceed the input threshold voltage. Intrinsic heart activity signals are amplified. Detected pacing pulses are attenuated. The system is capable of detecting an evoked response to determine whether a pacing pulse resulted in a successful heart contraction. Autocapture techniques allow adjustment of the pacing pulse energy based on the evoked response.

Abstract: A method and apparatus for attenuating polarization voltages or "afterpotentials" which develop at the heart tissue/electrode interface following the delivery of a pacing stimulus to the heart tissue such that the evoked response of the heart may be accurately detected to determine whether each pacing stimulus resulted in heart capture or contraction, thereby facilitating improved tracking of the capture threshold for minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor used to suppress DC components of the pacing pulse is reduced to effectively lower the equivalent capacitance of the pacing and coupling capacitors following delivery of the pacing pulse, allowing shorter recharge and blanking intervals. As a result, the evoked response is more easily detected.

Abstract: A method and apparatus for attenuating polarization voltages or "afterpotentials" which develop at the heart tissue/electrode interface following the delivery of a pacing stimulus to the heart tissue such that the evoked response of the heart may be accurately detected to determine whether each pacing stimulus resulted in heart capture or contraction, thereby facilitating improved tracking of the capture threshold for minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor used to suppress DC components of the pacing spike has a second, much lower capacitance capacitor connector in series with it, the second capacitor being shunted by a switch so that its value can be selectively inserted in series with the coupling capacitor to effectively lower the overall capacitance of the coupling capacitor following delivery of the pacing spike.

Abstract: A system and method for providing a 1:2 pacing therapy in response to a sensed ventricular tachycardia, which results in an improved hemodynamic response while limiting the potential for interrupting the tachycardia in a way that can cause a more dangerous tachycardia, or even VF. The pacing therapy involves obtaining a measure of the time interval between ventricular beats, and using this information to time out and deliver alternate stimulus pulses which occur just a short time interval (.DELTA.) before the next expected natural ventricular beat. By delivering the alternate cycle stimulus at a predetermined time interval before the expected ventricular beat, the advantage of increased arterial pressure on alternate spontaneous beats is obtained, while avoiding the danger of evoking a more dangerous arrhythmia. The system further monitors change in rate while therapy is being applied, and either adjusts the timing or exits the routine whenever significant rate change is detected.

Abstract: An apparatus effectively removes after potential occurring after a electrical pulse is delivered in a cardiac rhythm management system such as a pacemaker system or cardioverter/defibrillator system having an electrode used for both sensing electrical activity of the heart and carrying the electrical pulse to the heart and a sense amplifier for detecting the electrical activity from the electrode. The apparatus includes a lowpass filter coupled to the electrode to filter the sensed electrical activity. A highpass filter is coupled between the lowpass filter and the sense amplifier to further filter the electrical activity passed from the lowpass filter. Equilibrium circuitry is included to allow passive filter components of the lowpass filter and the highpass filter to return to an equilibrium state following delivery of the electrical pulse.

Abstract: A cardiac pacemaker system is provided which includes a stimulation electrode adapted for being anchored in the heart. An output capacitor is coupled to the stimulation electrode. A first circuit coupled to the output capacitor generates stimulation pulses. A second circuit coupled to the output capacitor generates an autoshort pulse following each stimulation pulse to reduce a residual charge of the output capacitor for eliminating an after potential following a stimulation pulse by the stimulation electrode. A third circuit coupled to the output capacitor acquires an evoked pulse of the heart from an electrical signal picked up by the stimulation electrode. The stimulation electrode includes a porous surface coating made of an inert material and has an active surface that is substantially larger than a surface of the basic geometric form of the stimulation electrode.

Abstract: Methods and apparatus are provided for generating multiphasic charge-balanced cardioversion and defibrillation shocks to apply to a patient's heart to terminate episodes of arrhythmia such as tachycardia and fibrillation. The time-integrated positive shock phase current equals the time-integrated negative shock phase current. The use of charge-balanced shocks has been determined to significantly reduce the effects of post shock block that result when conventional shocks are applied to the heart.

Abstract: An active discharge circuit for use within an implantable medical device, such as a pacemaker, rapidly discharges a coupling capacitor connected between a therapy circuit and body tissue. The active discharge circuit has a switching device, a charge transfer capacitor, and a clock. The clock is coupled to a control input of the switching device and provides a clock signal thereto. In response to the clock signal, the switching device sequentially and repeatedly couples the charge transfer capacitor to a discharge voltage supply so that charge transfers therebetween, and then couples the charge transfer capacitor to the coupling capacitor so that charge transfers therebetween. As the switch oscillates in response to the clock signal, the coupling capacitor is actively discharged.

Abstract: An implantable cardioverter-defibrillator (ICD) adaptively adjusts the refractory period and sensitivity setting of its sensing channel in order to optimally detect depolarization signals indicative of intrinsic cardiac rhythm or tachycardias, or depolarization signals indicative of fibrillation. In one embodiment, the ICD utilizes first and second depolarization signal processing channels, each having first and second refractory periods and first and second sensitivity settings, respectively. The sensitivity settings of the first processing channel are adaptively adjusted to sense normal depolarization signals and tachycardias. The sensitivity settings of the second processing channel are adaptively adjusted to sense fibrillation. Both the first and second refractory periods begin following either a paced depolarization or a sensed depolarization.

Abstract: An appliance for electrically stimulating tissue contractions of a living organism has circuitry for applying a stimulation potential to the tissue region to be stimulated and for applying a reference potential circuitry for detecting to the body of the living organism, stimulated tissue contractions. Following stimulation the stimulated tissue contraction is measured by a bipolar electrode between two adjacent tissue regions, the stimulation potential applied being to at least one of these tissue regions for the purpose of stimulating a tissue contraction.

Abstract: Disclosed is a pacemaker having an output circuit which is set to a high impedance when the potential of the input signal transmitted through the input-output terminal is within a predetermined range, and is set to a low impedance when the potential of the signal is outside of the range. Therefore, the time when the input to an R wave detection circuit must be stopped due to the after potential becomes extremely short and the failure of detection of an R wave decreases and, further, there are no rapid fluctuations in the potential arising due to the on-off operation of the switch. Further, the pacemaker of the invention may include a pulse lowering circuit for inputting a lowering pulse to the R wave detecting circuit so that the pacing pulse and the following after potential can't be detected as the R wave of the electrical activity of the heart.