Abstract: A cardiac rhythm management device is configured to detect oscillations in cardiac rhythm by comparing electrogram signals during successive heart beats. Upon detection of electrical alternans, the device may adjust its operating behavior to compensate for the deleterious effects of the condition.

Abstract: A pacing mode is provided, in one embodiment, that permits missed or skipped ventricular beats. The mode monitors a full cardiac cycle (A-A interval) for the presence of intrinsic ventricular activity. If ventricular activity is present, a flag is set that is valid for the next cardiac cycle. At the beginning of the next cardiac cycle, the device determines if the flag is present. So long as the flag is present, the device will not deliver a ventricular pacing pulse in that cycle, even if there is no intrinsic ventricular activity. If there is no flag present at the start of a given cardiac cycle, a ventricular pacing pulse is delivered and this ventricular activity sets a flag for the subsequent cardiac cycle.

Abstract: An extra-systolic stimulation (ESS) therapy addresses cardiac dysfunction including heart failure. ESS therapy employs atrial and/or ventricular extra-systoles via pacing-level stimulation to a heart. These extra-systoles must be timed correctly to achieve beneficial effects on myocardial mechanics (efficacy) while maintaining an extremely low level of risk of arrhythmia induction and excellent ICD-like arrhythmia sensing and detection (security). The present invention relates to therapy delivery guidance and options for improved ESS therapy delivery. These methods may be employed individually or in combinations in an external or implantable ESS therapy delivery device.

Abstract: Methods, apparatus, and systems are provided to stimulate multiple sites in a heart. A controller senses electrical activity associated with sinus rhythm of the heart. A signal generator is configured to generate an electrical signal for stimulating the heart. Based on the electrical signal, a distributor circuit then distributes the stimulating signals, such as pacing pulses, to a heart. The distributor circuit may vary the delay time between stimulating signals, inhibit a stimulating signal, trigger application of a stimulating signal, or vary the characteristics, such as the pulse width and amplitude, of a stimulating signal.

Abstract: An implantable cardiac device returns activations of corresponding right and left chambers of a heart to inter-chamber synchrony. A sensing circuit senses intracardiac signals representing right and left chamber ventricular electrical activity. A detector determines if a predetermined characteristic of the electrogram signals indicates dissociation of the corresponding right and left chambers. If dissociation is indicated, a pulse generator stimulates at least one of the corresponding chambers to restore inter-chamber synchrony.

Abstract: A method and system for managing refractory periods in a cardiac rhythm management device configured for biventricular or biatrial sensing. Refractory periods for each channel of the pacemaker are provided by interval timers that are triggered by sensed or paced events in order to prevent misinterpretation of sensing signals.

Abstract: In an implantable heart stimulating device, system and method, a control circuit has first and second circuits for sensing and pacing. The first circuit can be connected to a first electrode member suited to be positioned in or at a first ventricle of the heart. The second circuit can be connected to a second electrode member suited to be positioned in or at a second ventricle of the heart. The control circuit is able to detect whether signals sensed by the second circuit are likely to be far field signals. The control circuit performs this detection by at least determining whether, during a predetermined time (length, more signals are sensed by the second circuit than by the first circuit.

Abstract: A facial mask includes a mask body that is adapted to be coupled to a patient's face. A valve system is coupled to the mask body to permit the inflow of respiratory gasses into the mask body and to permit the outflow of respiratory gasses from the mask body. A metronome is coupled to the mask body to produce a repeating chest compression signal to facilitate the performance of regular chest compressions when performing cardio pulmonary resuscitation. The metronome may also produce a ventilation signal to facilitate the proper ventilation of the patient.

Abstract: A device and method for cardiac rhythm management in which a heart chamber is paced in accordance with sense signals from the opposite chamber or other distant cardiac site. The method is particularly useful in delivering cardiac resynchronization therapy.

Abstract: In one embodiment, a method includes sensing depolarizations of a heart at a plurality of different locations, and determining a sequence of the sensed depolarizations. The method may further include identifying a tachycardia condition and stimulating the heart at the plurality of locations based on the determined sequence. For example, the method may be implemented by an implantable medical device in order to improve anti-tachycardia pacing (ATP).

Abstract: A method for operating a cardiac pacemaker in which the mode of operation of the pacemaker is altered in response to detecting an episode of atrial tachycardia. In accordance with the invention, the pacemaker's pacing mode is altered in a manner that attempts to maintain hemodynamic stability during the atrial tachycardia. Such a mode switch is particularly applicable to pacemaker patients suffering from some degree of congestive heart failure.

Abstract: Methods and systems for providing cardiac therapy are described. In some embodiments, methods and systems are configured to deliver atrial tachyarrhythmia therapy by confirming that a patient is asleep and thereafter administering the therapy. Sleep can be confirmed, in some embodiments, through the use of a histogram that can be calculated using one or more parameters that are monitored by an implantable stimulation device. Parameters can include both physiological and non-physiological parameters. In other embodiments, atrial tachyarrhythmia therapy is delivered by determining desirable times to administer such therapy. Other various systems and methods for administering cardiac therapy are described.

Abstract: Methods and devices are disclosed for employing mechanical measurements to synchronize contractions of ventricular wall locations. Accelerometers that may be placed within electrode leads are positioned at ventricular wall locations, such as the left ventricle free wall, right ventricle free wall, and the anterior wall/septum wall. The accelerometers produce signals in response to the motion of the ventricular wall locations. A processor may then compare the signals to determine a difference in the synchronization of the ventricular wall location contractions. The difference in synchronization can be determined in various ways such as computing a phase difference and/or amplitude difference between the accelerometer signals. One or more stimulation pulses may be provided per cardiac cycle to resynchronize the contractions as measured by the accelerometers to thereby constantly and automatically optimize the cardiac resynchronization therapy.

Abstract: A method and apparatus for delivering cardiac resynchronization therapy (CRT) in which an evoked response electrogram is recorded during one or more cardiac cycles and used to aid in the selection of resynchronization pacing parameters and/or to monitor the effectiveness of resynchronization therapy. The morphology of an evoked response electrogram may be recorded and analyzed to determine if and when intrinsic activation of one ventricle is occurring in order to optimally adjust the programmed atrio-ventricular (AV) delay interval for ventricular resynchronization pacing of a patient with intact AV node conduction.

Abstract: Techniques are provided for coordinating the delivery of cardioversion therapy and overdrive pacing therapy to the heart of a patient, primarily to prevent the re-occurrence of atrial fibrillation (AF) following a cardioversion shock. Included are techniques for modulating the aggressiveness of overdrive pacing by adjusting the magnitude of overdrive pulses or by changing the electrodes with which overdrive pacing pulses are generated. In one example, three phases or “tiers” of AF suppression therapy are provided: cardioversion therapy; far-field dynamic atrial overdrive (DAO) pacing; and near-field DAO pacing. Briefly, a cardioversion shock is delivered to the heart of the patient in response to the detection of AF, then smoothed, far-field overdrive pacing pulses are delivered using widely-spaced electrodes for a period of two minutes while the magnitude of the pulses is gradually reduced.

Abstract: Techniques are provided for coordinating the delivery of cardioversion therapy and overdrive pacing therapy to the heart of a patient, primarily to prevent the re-occurrence of atrial fibrillation (AF) following a cardioversion shock. Included are techniques for modulating the aggressiveness of overdrive pacing by adjusting the magnitude of overdrive pulses or by changing the electrodes with which overdrive pacing pulses are generated. In one example, three phases or “tiers” of AF suppression therapy are provided: cardioversion therapy; far-field dynamic atrial overdrive (DAO) pacing; and near-field DAO pacing. Briefly, a cardioversion shock is delivered to the heart of the patient in response to the detection of AF, then smoothed, far-field overdrive pacing pulses are delivered using widely-spaced electrodes for a period of two minutes while the magnitude of the pulses is gradually reduced.

Abstract: A cardiac rhythm management device is configured to detect oscillations in cardiac rhythm by comparing electrogram signals during successive heart beats. Upon detection of electrical alternans, the device may adjust its operating behavior to compensate for the deleterious effects of the condition.

Abstract: An implantable cardiac stimulating device has an atrial pulse generator and an atrial sensor connected to an atrial electrode, for delivering stimulating pulses to the atrium and sensing events in the atrium. The stimulating device also has a ventricular pulse generator and a ventricular sensor connected to a ventricular electrode for delivering stimulating pulses to the ventricle and for sensing events in the ventricle. The ventricular sensor also includes an evoked response detector. A control unit causes the ventricular pulse generator to deliver a back-up pulse if no evoked response is detected. The control unit operates the atrial pulse generator in a first manner wherein no stimulating pulse is delivered to the atrium and in a second manner wherein stimulating pulses are delivered to the atrium.

Abstract: Techniques are presented for providing adjustable cardiac resynchronization with an implanted medical device such as a pacemaker. For example, cardiac resynchronization may be provided during some time periods but not during other time periods, or cardiac resynchronization may be provided in response to selected sensed events. Adjustable cardiac resynchronization is applicable to therapy such as bi-ventricular pacing, in which both ventricles of the heart are paced in response to sensed atrial events.

Abstract: A method and system for pacing cardiac tissue is provided. Atrial fibrillation is detected in the cardiac tissue. An area of the cardiac tissue is paced with at least one atrial electrode and simultaneously paced with at least one ventricular electrode. A ventricular extra-systole is induced, thereby terminating the atrial fibrillation.

Abstract: A method and device for performing anti-tachycardia pacing (ATP) to convert a ventricular tachycardia (VT) to normal sinus rhythm. Pairs of pacing/sensing electrodes are placed in or on each of the left and right ventricles. A determination is made whether a reentrant loop responsible for the VT is closer to one or the other of the pacing/sensing electrode pairs. ATP is performed with the pair of electrodes closest to the reentrant loop.

Abstract: An implantable cardiac stimulation device and method automatically verify capture of one or both ventricular chambers by sensing a far-field signal in both atrial chambers. A far-field interval window is set following the delivery of the ventricular stimulation, during which a far-field signal is detected and compared to a signal representing a predetermined far-field R-wave that represents successful capture of one or both ventricular chambers. If the far-field signal is approximately equal to the predetermined far-field R-wave signal, then capture is verified. If capture is not verified, a threshold search is performed in the ventricle in which capture was lost.

Abstract: An implantable universal pacing and defibrillating system provides efficacious sensing, pacing, and cardioversion/defibrillation in all four chambers of the heart. The system includes three leads with one lead being configured for implant in the coronary sinus for sensing, pacing, and defibrillating in both the left atrium and left ventricle. The leads also provide a plurality of different electrode configurations for both ventricular and atrial defibrillation. Sequential primary and secondary defibrillation shocks may be employed to advantage for depolarizing essentially all of the ventricular or atrial myocardium.

Abstract: Improved methods and devices for performing anti-tachycardia pacing (ATP) to convert a ventricular tachycardia (VT) to normal sinus rhythm. In one embodiment one of a plurality of pacing configurations are selected for performing ATP. The selection can be based on the morphology of a signal indicative of the tachycardia.

Abstract: A cardiac rhythm management device includes a dual chamber pacemaker, especially designed for treating congestive heart failure by pacing a plurality of sites. The device incorporates a program microcontroller which is operative to adjust the pacing mode and inter-site delay of the pacemaker so as to achieve optimum hemodynamic performance. Atrial cycle lengths measured during transient (immediate) time intervals following a change in the mode inter-site delay are signal processed and a determination can then be made as to which particular configuration yields the optimum performance. Performance is optimized when the patient is at rest and when the patient exercises so that a rate-adapted dynamic value of the optimum performance can be applied.

Abstract: A cardiac electro-stimulatory device and method for operating same in which stimulation pulses are distributed among a plurality of electrodes fixed at different sites of the myocardium in order to reduce myocardial hypertrophy brought about by repeated pacing at a single site and/or increase myocardial contractility. In order to spatially and temporally distribute the stimulation, the pulses are delivered through a switchable pulse output configuration during a single cardiac cycle, with each configuration comprising one or more electrodes fixed to different sites in the myocardium.

Abstract: An active implantable medical device, in particular a pacemaker, defibrillator and/or cardiovertor of the multisite type, capable of detecting an induced tachycardia. Such a device is to be coupled to electrodes placed in at least two cardiac sites of the same cardiac chamber type, e.g., at least two ventricular sites, right and left, at least two atrial sites, right and left, or at least two sites of the same cavity (atria or ventricular). The device has a cardiac signal collection circuit to detect a depolarization potential, and a stimulation circuit to apply stimulation pulses to at least certain of the aforesaid sites.

Abstract: A defibrillator which contains a device for producing alternating voltage, a power factor controller for converting the alternating voltage to a direct voltage, and a device for converting the direct voltage into a biphasic waveform voltage. The defibrillator also contains a device for sensing the electrical activity of a human heart and for allowing one to hear an audio signal corresponding to such activity.

Abstract: A device and method for cardiac rhythm management in which a heart chamber is paced in accordance with sense signals from the opposite chamber or other distant cardiac site. In an exemplary embodiment, a rate chamber and a synchronized chamber are defined. The synchronized chamber is then paced in accordance with a synchronized pacing mode such that a synchronized chamber pace is delivered at a specified pacing instant defined with respect to expiration of a rate chamber escape interval based upon rate chamber events. The method is particularly useful in delivering cardiac resynchronization therapy.

Abstract: A method and system for managing refractory periods in a cardiac rhythm management device configured for biventricular or biatrial sensing. Refractory periods for each channel of the pacemaker are provided by interval timers that are triggered by sensed or paced events in order to prevent misinterpretation of sensing signals.

Abstract: Techniques are described for pacing multiple sites in a patient's heart using overdrive pacing the heart using a pacemaker including techniques where the overdrive pacing rate only increases when at least two intrinsic beats are detected within a determined search period. In one specific technique, an increase in the pacing rate occurs only if two P-waves are detected within X cardiac cycles. In another specific technique, the overdrive pacing rate is increased only if at least two P-waves are detected within a block of N cardiac cycles. In both techniques, the overdrive pacing rate is decreased if no increase has occurred in the last Z cardiac cycles. By increasing the overdrive pacing rate only in response to detection of at least two P-waves within a determined number of cardiac cycles, an excessively high overdrive pacing rate is avoided.

Abstract: A system and method recording sensing and pacing events in a cardiac rhythm management device. The method may be particularly useful in assessment of pacing parameters for ventricular resynchronization therapy.

Abstract: An active implantable medical device, such as a pacemaker, defibrillator, cardiovertor and/or a multisite device, having an improved detection of late atrial extrasystoles. The device detects atrial events (EvtA); applies a first window forming a relative atrial refractory period (DARRP) for discriminating (filtering) atrial extrasystoles of an early or average prematurity, and reacts to a variation of the sinusal atrial rate by certain control algorithms. It also applies the detected atrial events to a second window (DLE), distinct from the first window and of longer duration, for the discrimination of the atrial extrasystoles having a low prematurity, called late extrasystoles. The duration of the second window is a variable duration, defined as a fraction of the current average atrial interval (AAI). Further, the second window is used to inhibit temporarily any reaction to a variation of the sinusal atrial rate, in the event of detection of an atrial event inside the second window.

Abstract: A method and apparatus for controlling a segment of excitable tissue, typically tissue of a heart, the segment having an intrinsic activity level. During a high phase, electrical energy of a given amplitude is applied to the segment. During a low phase, the amplitude of the electrical energy applied to the segment is reduced relative to that applied during the high phase, so that the segment's activity level increases during the low phase above the intrinsic activity level.

Abstract: An implantable system for detecting electrical activity from a patient's heart comprises a first sensing electrode configured for positioning through the coronary sinus ostium and within a vein on the left surface of the left ventricle of the heart for sensing electrical activity from the heart, and a detector operatively associated with the first sensing electrode for determining (e.g., diagnosing or prognosing) a medical condition of the heart with the sensed electrical activity. Typically the system further comprises a second sensing electrode configured for positioning in the right ventricle of the heart, where the detector is operatively associated with both the first sensing electrode and the second sensing electrode. The second sensing electrode may be positioned in other locations as well, such as also within a vein on the left surface of the left ventricle of the heart (although spaced apart from the first sensing electrode), in the right atrium, in the superior vena cava, etc.

Abstract: An implantable anti-arrhythmia system which includes a spinal cord stimulator and an implantable heart rhythm monitor, coupled to control the spinal cord stimulator. The implantable heart monitor is adapted to detect the occurrence of tachyarrhythmias or of precursors thereto and in response, trigger the operation of the spinal cord stimulator in order to prevent occurrences of tachyarrhythmias and/or as a stand-alone therapy for termination of tachyarrhythmias and/or to reduce the level of aggressiveness required of an additional therapy such as antitachycardia pacing, cardioversion or defibrillation. The device in most embodiments is expected to include a mechanism for delivering an electrical anti-tachyarrhythmia therapy such as pacing, cardioversion or defibrillation in response to detection of a tachyarrhythmia. However, in some embodiments the spinal cord stimulator may be the only electrical stimulator included in the system.

Abstract: A multi-site pulse generator for the treatment of cardiac insufficiencies by stimulation. In such a multi-site cardiac pulse generator, electrodes are placed in a plurality of distinct respective sites, including at least two ventricular sites. The electrodes are connected to independent outputs of the pulse generator in a manner that allows the detection of a potential of depolarization as well as the application of a stimulation pulse.

Abstract: A method and system for applying therapeutic electrical pulses to the heart includes a plurality of spaced apart electrodes. Each electrode in electrical communication with a pulse generator and are operative to deliver at least one energy pulse to a patient's heart. Sensors and electrical communication with a controller are operative to detect an abnormal rhythm in the patient's heart and transmit a signal to a controller to indicate an abnormal rhythmic condition. The controller is configured to receive the abnormal rhythmic signal from the sensor and cause the pulse generator to emit a sequence of spatially and temporally distinct pulses through the electrodes, each pulse passing through at least one of the electrodes.

Abstract: A device and process for the processing of troubles of the atrial rhythm for an active implantable medical device. The device detects signals from at least the atrial cardiac activity, and stimulates both the atrial and ventricular cardiac cavities, detects the occurrence of atrial extra-systoles (ESA), and determines and releases an intermediate atrial escape interval (PPinter). The intermediate atrial escape interval is then applied during the detection of an atrial extra-systole for improved processing.

Abstract: In an apparatus for terminating atrial fibrillation using pulses having an energy content which is the same as the energy content of conventional pacing pulses, stimulation pulses are respectively emitted by a number of electrodes disposed at different sites in or on a heart experiencing atrial fibrillation. When atrial fibrillation is detected, waveforms are measured at each of the electrodes, and the electrode having the waveform exhibiting the shortest interval between successive identifiable, cyclical waveform characteristics, such as successive P-waves, is selected as a first electrode for beginning an atrial defibrillation attempt. Stimulation pulses are emitted from the first electrode at a stimulation rate which is slightly shorter than the aforementioned shortest interval and the other electrodes are stimulated at a rate which is slightly shorter than the rate for the first electrode. All of the stimulation pulses are delivered starting at the latest local detection point in time.

Abstract: New pacing algorithm defines faster than indicated pacing rate during detection of PAC's/PVC's and reduces rate after awhile to a safety rate unless natural depolarizations are detected.

Abstract: A process for the treatment of atrial arrhythmia by use of ablation and/or mapping procedures comprising ablating discrete ablation tracks within the left and right atrium of the heart by use of precurved left and right atrium guiding introducers, including preferably a guiding introducer system for use in the left atrium comprising an inner and an outer guiding introducer. Also disclosed are shapes for the guiding introducers and the guiding introducer system to be used for the ablation and/or mapping of the discrete tracks within the left and right atrium.

Abstract: A heart stimulator for detecting atrial tachycardia, contains a control device to which are connected an atrial detector, having a blanking period, for detecting atrial events, a ventricular stimulation unit for delivering stimulation pulses in the ventricle, a counter for generating a variable PV interval between a detected atrial event and a stimulation pulse delivered in the ventricle, a time measurement unit for measuring time between two consecutive, detected atrial events and a calculation unit which, in a test mode for determining of whether atrial tachycardia is present, is arranged to cause the counter to generate a PV interval so the PV interval plus the atrial detector's blanking period is equal to half or less than half of an adjustable threshold level PP tachycardia. The time measurement unit sends a detection signal to the control device when a defined number of measured, consecutive PP intervals is less than a defined threshold value PP for the PP interval (threshold value PP tachycardia).

Abstract: Improved methods and apparatus are provided for applying atrial and ventricular therapies to the heart of a patient using an implanted cardiac stimulating device. Atrial and ventricular heart rates are monitored and analyzed to determine whether the patient is suffering from an atrial or ventricular arrhythmia and to determine what type of therapy is appropriate to apply to the heart. Atrial and ventricular heart rates are compared to determine if the ventricular heart rate exceeds the atrial heart rate and to determine whether the ventricular heart Fate is stable. An early atrial stimulation pulse can also be applied to determine whether the ventricular heart rate follows the atrial heart rate. Atrial and ventricular therapies are applied to the heart based on these determinations.

Abstract: Control of a double atrial triple chamber cardiac pacemaker having a programmable fallback mode. The triple chamber pacemaker has a right atrial electrode and a left atrial electrode connected to the same atrial detection/stimulation circuit, as well as a ventricular electrode connected to a ventricular detection/stimulation circuit of the pacemaker. The fallback mode involves desynchronization of the ventricular stimulation from the detected atrial rhythm when the atrial rhythm is too rapid. The pacemaker also includes a fallup mode of pacing in which there is a progressive re-synchronization of ventricular stimulation to the atrial rhythm when the atrial rhythm falls to a less rapid rhythm.

Abstract: A process for the treatment of atrial arrhythmia by use of ablation and/or mapping procedures comprising ablating discrete ablation tracks within the left and right atrium of the heart by use of precurved left and right atrium guiding introducers. Also disclosed are shapes for the guiding introducers to be used for the ablation and/or mapping of the discrete tracks within the left and right atrium.

Abstract: An implantable dual-chamber pacemaker programmed to operate primarily in an atrial tracking mode is provided, where the pacemaker includes an atrial rate smoothing filter for producing a filtered atrial rate from an intrinsic atrial rate, and where the pacemaker automatically switches its mode of operation from the atrial tracking mode to a non-atrial tracking mode in the event the filtered atrial rate exceeds a prescribed upper rate limit. The pacemaker switches from a primary set of operational parameter settings for the primary mode, to an alternate set of operational parameters for the alternate mode when the mode is switched from the primary mode to the alternate mode. The pacemaker also includes the capability of recording and storing mode switching events and data pertaining to the mode switching events.

Abstract: An implantable defibrillator having programmable shock waveforms and paths where each successive waveform may be of a different shape and form, and delivered to and through an area of the human heart in a desired sequence. The shock waveforms can be delivered independently through certain areas of the heart or through different areas of the heart to the can electrode or to a patch electrode at a computed common time. Alternatively, a first shock waveform or set of shock waveforms can be delivered through one or more areas of the heart followed by a delivery of time sequenced delayed shock waveform or forms through specific areas of the heart to the can electrode or patch electrode.

Abstract: A device-implemented method detects and treats abnormal (i.e., pathologic) tachycardias experienced by a patient with an implanted automatic defibrillator. The defibrillator has the capability to distinguish pathologic tachycardia from physiologic tachycardia by the application of predetermined distinction criteria programmed into it. Changes in a physiologic parameter of the patient which signify a physiologic basis for increase or decrease of the patient's heart rate are detected, and in response, the distinction criteria are modified to enhance the capability of the defibrillator to make the distinction between pathologic and physiologic tachycardia when this change in circumstances that would otherwise tend to obscure the distinction is factored in. In one method, the parameter under detection is patient activity, and the distinction criteria include a threshold heart rate above which the patient is presumed to be experiencing a pathologic tachycardia.

Abstract: An improved implantable cardioverter defibrillator (ICD) system having a programmable switched and variable range of effective output capacitance values for the purpose of producing a capacitive-discharge countershock. The improvement comprises a pulse generating capacitor arrangement for the ICD system that includes two or more separate capacitor systems and a system for selectively electrically connecting each of the capacitor systems in parallel with the other capacitor systems during the charging and discharging of the pulse-generating capacitor arrangement, such that the pulse generating capacitor arrangement has at least two different selectable effective output capacitance values. With this type of capacitor arrangement, it is possible to reduce the countershock energy in discrete steps as the duration of the countershock is decreased, while still preserving the value of the initial discharge voltage, and hence the conversion effectiveness.