Abstract: A medical device and associated method deliver cardiac pacing in a dual chamber pacing mode and schedule an atrial-ventricular (AV) conduction check during the dual chamber pacing mode to detect the presence of AV conduction. If AV conduction is detected during the scheduled AV conduction check, the medical device switches to an atrial pacing mode and switches back to the dual chamber pacing mode in response to an absence of AV conduction during the atrial pacing mode. The detected AV conduction is identified as a false positive detection in response to the pacing mode switch to the dual chamber pacing mode occurring within a predetermined interval of time from detecting the AV conduction.

Abstract: A system for the detection of cardiac events occurring in a human patient is provided. At least two electrodes are included in the system for obtaining an electrical signal from a patient's heart. An electrical signal processor is electrically coupled to the electrodes for processing the electrical signal and a patient alarm means is further provided and electrically coupled to the electrical signal processor. The electrical signal is acquired in the form of electrogram segments, which are categorized according to heart rate, ST segment shift and type heart rhythm (normal or abnormal). Baseline electrogram segments are tracked over time.

Abstract: A system and method is disclosed for system fault recovery by an implantable medical device which employs a global fault response. The system enables the device to consistently recover from transient faults while maintaining a history of the reason for the device fault. Upon detection of a fault, the primary controller of the device signals a reset controller which then issues a reset command. All sub-systems of the primary device controller are then reset together rather than resetting individual sub-systems independently to ensure deterministic behavior.

Abstract: Atrial capture threshold testing is performed in accordance with an atrial capture threshold testing schedule. Monitoring for retrograde P-waves occurs at least during times other than times during which scheduled atrial capture threshold testing is performed. In response to detecting a retrograde P-wave indicative of sub-threshold atrial pacing during monitoring, an unscheduled atrial capture threshold test is performed and pacing of the atrium is adjusted based on the unscheduled atrial capture threshold test.

Abstract: Cardiac devices and methods discriminate non-captured intrinsic beats during evoked response detection and classification by comparing the features of a post-pace cardiac signal with expected features associated with a non-captured response with intrinsic activation. Detection of a non-captured response with intrinsic activation may be based on the peak amplitude and timing of the cardiac signal. The methods may be used to discriminate between a fusion or capture beat and a non-captured intrinsic beat. Discriminating between possible cardiac responses to the pacing pulse may be useful, for example, during automatic capture verification and/or a capture threshold test.

Abstract: A medical device and method for determining a parameter for delivery of a predetermined pacing therapy that includes a plurality of electrodes to deliver a pacing therapy, including the predetermined pacing therapy, and a control unit to control the timing of the delivery of the pacing therapy, including the predetermined pacing therapy, by the electrodes. A processor generates a first template in response to the pacing therapy being delivered to only one of a right ventricle and a left ventricle, and a second template in response to the pacing therapy being delivered to only the other of the right ventricle and the left ventricle, and determines the parameter in response to a comparing of subsequently delivered pacing therapy to the first template and the second template.

Abstract: A method, system, and apparatus for implementing a safe mode operation of an implantable medical system using impedance adjustment(s) are provided. A first impedance is provided to a lead. An indication of a possibility of a coupled energy is received. Based upon said indication, a second impedance associated with the lead to reduce the coupled energy is provided.

Abstract: An interactive implantable medical device system includes an implantable medical device and a network-enabled external device capable of bi-directional communication and interaction with the implantable medical device. The external device is programmed to interact with other similarly-enabled devices. The system facilitates improved patient care by eliminating unnecessary geographic limitations on implantable medical device interrogation and programming, and by allowing patients, physicians, and other users to access medical records, history, and information and to receive status and care-related alerts and messages anywhere there is access to a communications network.

Abstract: In a method and medical system for determining a link quality and a link quality margin of a communication link between a programmer device and an implantable medical device of such a medical system, a link quality monitoring circuit of the programmer or the medical device a present link quality and/or link quality margin at reduced signal power using at least one link quality parameter.

Abstract: Bio-impedance may be used for navigation systems to chronically implant pacing and defibrillation leads in the heart using a non-fluoroscopic position sensing unit (PSU). Such a system requires that a conductive material, such as a retractable helical tip-electrode, be exposed during implantation. Since the tip is retracted during implantation, this disclosure provides a modified distal portion employing at least one aperture (or “window”) for fluid exposure of the helix-electrode and a deployable internal sleeve for covering the aperture(s) when the helix-electrode is extended.

Abstract: A remaining charge capacity of a battery having an initial charge capacity is monitored. The battery powers a remote implantable medical device (IMD) that includes an active state, during which the remote IMD performs at least one function, and an inactive state, during which the remote IMD performs no functions. An active state charge consumption is computed based on stored parameters associated with an operational charge consumption for each function, and an inactive state charge consumption is computed based on a leakage current associated with the inactive state and a time the remote IMD is in the inactive state. The active state charge consumption and inactive state charge consumption are subtracted from the initial charge capacity to determine the remaining charge capacity.

Abstract: An intrinsic inter-atrial conduction delay is determined by a pacemaker or implantable cardioverter-defibrillator based, at least in part, on far-field atrial events sensed using ventricular pacing/sensing leads. An atrioventricular pacing delay is then set based on the inter-atrial conduction delay. By detecting atrial events using ventricular leads, rather than using atrial leads, a more useful measurement of the intrinsic inter-atrial conduction delay can be obtained. In this regard, since atrial electrodes detect atrial activity locally around the electrodes, a near-field atrial event sensed using an atrial electrode might not properly represent the actual timing of the atrial event across both the right and left atria. Far-field atrial events sensed using ventricular leads thus allow for a more useful measurement of inter-atrial conduction delays for use in setting atrioventricular pacing delays.

Abstract: An active implantable medical device including bidirectional communications between a generator and sensors or actuators located at the distal extremity of a lead. A lead (14) is connected at its proximal end to a generator (10) and has at the distal end electrodes (38, 42) able to come in contact with surrounding tissues. A two-wire connection (34, 36) connects these electrodes to the generator. The lead incorporates transducers (24, 26) of sensor or actuator type. The generator includes circuits for sending and receiving digital data (46,48,50,54,56) capable of producing instructions to one of the transducers and to receive and decode information from one of the transducers in response to a specific instruction produced by the generator. The transducer is able to receive, decode and carry out the aforementioned controls, as well as send data in response.

Abstract: Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

Abstract: An implantable medical device includes a lead, a pulse generator, an autocapture module, an autothreshold module, a fusion detection module, and a control module. The lead includes electrodes configured to be positioned within a heart. At least one of the electrodes is capable of sensing cardiac signals. The pulse generator delivers a stimulus pulse through at least one of the electrodes. The autocapture module senses an evoked response of the heart after delivery of the stimulus pulse when operating in an autocapture mode. The autothreshold module performs a threshold search when operating in an autothreshold mode. The fusion detection module identifies fusion-based behavior in the heart. The control module automatically switches between the autothreshold and autocapture modes based on a presence of the fusion-based behavior.

Abstract: Tools and methods are particularly suited for certain cardiac conditions involving use of a catheter for pacing of the right and left ventricles from a lead in the right ventricle, e.g., to facilitate mechanically and/or electrically synchronous contractions for resynchronization. Certain aspects involve pacing and/or mapping by generating pulses for delivery to a cardiac site useful for improving heart function as measured, e.g., by QRS width, fractionation, late LV activation timing, mechanical synchronicity of free wall and septal wall, effective throughput/pressure, or a combination thereof. In one embodiment, an implantable pulse generator includes circuitry for generating pacing profiles, with signals of opposite polarities, specifically selected for delivery on electrodes at a site near the septal wall of a right ventricle of the heart.

Abstract: A method for selectively interacting with electrically excitable tissue of a patient is provided. In one configuration, an implantable pulse generator with a number of outputs and an array of electrodes with a number of electrodes being greater than the number of outputs may be implanted in a patient. An extension unit may be implanted between the implantable pulse generator and array. The extension unit acts to electrically couple the inputs of implantable pulse generator with the greater number of electrodes in the array so that the output sources are coupled to a portion of the electrodes.

Abstract: A system and method for passively testing a cardiac pacemaker in which sensing signal amplitudes and lead impedance values are measured and stored while the pacemaker is functioning in its programmed mode. The amplitude and impedance data may be gotten and stored periodically at regular intervals to generate a historical record for diagnostic purposes. Sensing signal amplitudes may also be measured and stored from a sensing channel which is currently not programmed to be active as long as the pacemaker is physically configured to support the sensing channel. Such data can be useful in evaluating whether a switch in the pacemaker's operating mode is desirable.

Abstract: An implantable heart stimulating device has an ECG sensing unit to receive heart potential signals from sensing electrodes at an electrode lead arranged in connection with a patient's heart. The ECG sensing unit is provided with a programmable make-break threshold. The device further has a timer adapted to generate a make-break detection period, and a counter. The counter is adapted to count the number of times that the amplitude of the heart potential signal exceeds the programmable make-break threshold during the make-break detection period. When the number of times is higher than a predetermined value, the ECG obtained during the make-break detection period is stored in an ECG storage unit.

Abstract: In an implantable medical device, in particular an implantable heart-stimulation device, and a method for operating an implantable heart-stimulation device and a heart-stimulation system, stimulation pulses are delivered via a number of stimulation channels to selected sites on or about a patient's heart via electrodes, and wherein coupling capacitors included in the stimulation channels are subsequently discharged through a sequence of temporally non-overlapping partial discharges of the respective coupling capacitors. By this configuration, the risk of charge neutrality of a stimulation channel not being maintained at the end of a stimulation sequence, comprising the delivery of stimulation pulses via stimulation channels, is reduced or eliminated.

Abstract: Techniques for determining whether a lead related condition exists based on a correlation between a parameter indicative of impedance of a lead and a parameter indicative of motion of the lead. In some examples, the techniques include generating an electrical signal that is indicative of impedance of the lead, generating an electrical signal that is indicative of motion of the lead, and monitoring the frequency, amplitude, and phase of the electrical signals in order to identify a correlation. In some examples, if a lead related condition is identified, an alert is provided or a sensing or therapy modification is suggested.

Abstract: A system for controlling an implantable medical device (e.g., a drug delivery device) susceptible to malfunctioning during exposure to a magnetic field and/or Radio Frequency field (e.g., during a magnetic resonance imaging procedure) and a method for operating the same. Exposure of the implantable device to the magnetic field and/or the Radio Frequency field is detected using the sensing device. When the detected magnetic field and/or Radio Frequency field exceeds a corresponding predetermined threshold level, an input signal is generated at the microcontroller.

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: Disclosed are certain methods, apparatus, and processor-readable mediums that may be used to treat a conduction abnormality of the heart. In one example, the apparatus includes an implantable pacing profile generator configured to generate a specified pacing electrostimulation profile for delivery to a heart via electrodes located near a septal region of the right ventricle of the heart near the His bundle, the pacing profile including a first pulse for delivery via a first electrode; and a second pulse for delivery via a second electrode; and wherein the first and second pulses are at least partially concurrent in time and opposite in polarity to each other.

Abstract: A method and an apparatus for projecting an end of service (EOS) and/or an elective replacement indication (ERI) of a component in an implantable device and for determining an impedance experienced by a lead associated with the implantable device. An active charge depletion of an implantable device is determined. An inactive charge depletion of the implantable device is determined. A time period until an end of service (EOS) and/or elective replacement indication (ERI) of a power supply associated with the IMD based upon the active charge depletion, the inactive charge depletion, and the initial and final (EOS) battery charges, is determined. Furthermore, to determine the impedance described above, a substantially constant current signal is provided through a first terminal and a second terminal of the lead. A voltage across the first and second terminals is measured. An impedance across the first and second terminals is determined based upon the constant current signal and the measured voltage.

Abstract: A system for automatically evaluating the sensing and detection of physiological processes by an implantable medical device, such as an implantable cardiac stimulation device. The system includes an automatic testing algorithm which iteratively adjusts at least one of the threshold and gain settings of the device and evaluates the accuracy of the detection for refining the programming of the device. The algorithm can include sampling the physiological process beginning at a relatively low rate to avoid excessive burden on the processing and battery capacity available and progressively increasing the rate to obtain higher resolution data. The algorithm can also evaluate the observed physiological process for periodicity and can determine repetition of an irregular pattern, such as bigeminy, and use the determined pattern for predictive purposes to refine the programming of the device. The algorithm employs observation of a change in observed pattern as indicia for loss of proper detection.

Abstract: In general, the disclosure is directed to techniques for identification and remediation of oversensed cardiac events using far-field electrograms (FFEGMs). Identification of oversensed cardiac events can be used in an ICD to prevent ventricular fibrillation (VF) detection, and thereby avoid delivery of an unnecessary defibrillation shock. Alternatively, or additionally, identification of oversensed cardiac events can be used in an ICD to support delivery of bradycardia pacing during an oversensing condition. In some cases, bradycardia pacing delivered in response to detection of oversensed cardiac events may include pacing pulses from multiple vectors to provide redundancy in the event the oversensing may be due to a lead-related condition.

Abstract: A method and system for determining undersensing during post-processing of sensing data generated by a medical device that includes transmitting a plurality of stored sensing data generated by the medical device to an access device, the stored sensing data including sensed atrial events and sensed ventricular events. The access device determines, in response to the transmitted data, instances where the medical device identified a cardiac event being detected in response to the sensing data, and determines whether one of a predetermined number of undersensing criteria have been met in response to the transmitted data.

Abstract: A method and apparatus are disclosed for automatic self-test of a medical device. The method includes detecting whether the medical device has reached an automatic self-test time set in the last time, when the medical device is in a power-off state. If the result of the detecting is affirmative, the method includes initiating the medical device to perform automatic self-test according to determined automatic self-test items, and determining the automatic self-test time of the next time for the medical device based on the result of the automatic self-test. The automatic self-test time and the automatic self-test items are relatively flexible so as to avoid the unnecessary consumption of electricity and the unnecessary wear-and-tear of the instrument caused by unnecessary automatic self-test.

Abstract: A method for operating an implantable medical device to control a stimulation therapy includes the steps of: sensing an acoustic energy; producing acoustic signals indicative of heart sounds of the heart of the patient over predetermined periods of a cardiac cycle during successive cardiac cycles; extracting a signal corresponding to a first heart sound (S1) from a measured acoustic signal; calculating an energy value corresponding to the extracted signal; storing the energy value corresponding to the first heart sound; and initiating an optimization procedure, the optimization procedure comprising the steps of: iteratively controlling a delivery of the pacing pulses based on successive energy values corresponding to successive first heart sound signals and determining an optimal PV interval or AV interval with respect to the energy values. A medical device and a computer readable medium to implement the method.

Abstract: An implantable cardiac rhythm management system includes a user interface, such as an external programmer, for performing therapy energy threshold tests. The threshold tests allow the caregiver to determine the threshold energy at which paces capture the heart, i.e., cause a resulting contraction of the heart chamber to which the paces are delivered. The programmer provides recorded indications of the energy corresponding to each paced event, so that the caregiver can easily determine the point at which capture was lost. This recorded representation of pacing energy makes it easy for the caregiver to determine proper pacing thresholds to be used to ensure adequate pacing, while minimizing energy drain to prolong the useful life of the implanted device.

Abstract: An apparatus comprises an implantable medical device that includes a storage circuit. The storage circuit includes a first stage circuit configured to receive an input signal and to invert and store information about a data bit received in the input signal, a second stage circuit coupled to the output of the first stage circuit to invert and store information about a data bit received from the first stage circuit, and an error circuit coupled to the output of the first stage circuit and an output of the second stage circuit. The error circuit generates an error indication when the storage circuit outputs match while the first stage circuit and the second stage circuit are in an inactive state.

Abstract: Techniques for determining whether artifacts are present in a cardiac electrogram are described. According to one example, a medical device senses a cardiac electrogram via electrodes. The medical device determines a derivative, e.g., a second order derivative, the electrogram. The medical device detects beats within the derivative, e.g., by comparing a rectified version of the derivative to one or more thresholds determined based on a maximum of the rectified derivative. The medical device determines whether the beats are periodic, and determines whether artifacts are present in the cardiac electrogram based on the determination of whether the beats are periodic. The medical device may further determine whether tachyarrhythmia is present and/or whether the cardiac rhythm of the patient is treatable based on the determination of whether the beats are periodic. For example, the medical device may determine that an electrogram is not treatable when the beats are periodic.

Abstract: Methods and systems for detecting capture using pacing artifact cancellation are described. One or more pacing artifact templates are provided and a cardiac signal is sensed in a cardiac verification window. Each of the pacing artifact templates may characterize the pacing artifact associated with a particular pacing energy level, for example. A particular pacing artifact template is canceled from the cardiac signal. Capture is determined using the pacing artifact canceled cardiac signal. Detection of fusion/pseudofusion beats may be accomplished by comparing a cardiac signal to a captured response template.

Abstract: A system and method for passively testing a cardiac pacemaker in which sensing signal amplitudes and lead impedance values are measured and stored while the pacemaker is functioning in its programmed mode. The amplitude and impedance data may be gotten and stored periodically at regular intervals to generate a historical record for diagnostic purposes. Sensing signal amplitudes may also be measured and stored from a sensing channel which is currently not programmed to be active as long as the pacemaker is physically configured to support the sensing channel. Such data can be useful in evaluating whether a switch in the pacemaker's operating mode is desirable.

Abstract: An implantable medical device operates with an algorithm that promotes intrinsic conduction and reduces ventricular pacing. The IMD monitors the occurrence of necessary ventricular pacing and takes certain actions based upon whether this occurrence has been relatively high or relatively low. When noise is detected, asynchronous pacing is provided when the occurrence is relatively high and is not provided when relatively low. When atrial threshold testing is performed, the incidence will determine which methodology is utilized.

Abstract: An implantable pulse generator senses a cardiac signal, identifies cardiac events in the cardiac signal, and starts a blanking interval including a repeatable noise window blanking interval in response to each cardiac event. When noise is detected during the repeatable noise window blanking interval, the noise window blanking interval is repeated. In one embodiment, the duration of repeated repeatable noise window blanking intervals is summed and compared to a pacing escape interval. When the sum is greater than the pacing escape interval, asynchronous pacing pulses are delivered until the noise ceases. Alternatively, when the sum is greater than the pacing escape interval, the pace escape interval is repeated.

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: A method and system for verifying capture in the heart involves the use of pacing artifact templates. One or more pacing artifact templates characterizing a post pace artifact signal associated with a particular pace voltage or range of voltages are provided. A pacing artifact template is canceled from a cardiac signal sensed following a pacing pulse. Capture is detected by comparing the pacing artifact canceled cardiac signal to an evoked response reference. Fusion/pseudofusion detection involves determining a correlation between a captured response template and a sensed cardiac signal.

Abstract: Apparatus for storing data records associated with a medical monitoring event in a data structure. Upon indication by a patient of a possible manifestation of a neurological event, the implanted device obtains and stores data in the data record in a first data structure that is age-based. Before an oldest data record is lost, the oldest data record may be stored in a second data structure that is priority index-based. The priority index may be determined by a severity level and may be further determined by associated factors. The implanted device may organize, off-load, report, and/or display a plurality of data records based on an associated priority index. Additionally, the implanted device may select a subset or composite of physiologic channels from the available physiologic channels based on a selection criterion.

Abstract: Vector selection is automatically achieved via a thoracic or intracardiac impedance signal collected in a cardiac function management device or other implantable medical device that includes a test mode and a diagnostic mode. During a test mode, the device cycles through various electrode configurations for collecting thoracic impedance data. At least one figure of merit is calculated from the impedance data for each such electrode configuration. In one example, only non-arrhythmic beats are used for computing the figure of merit. A particular electrode configuration is automatically selected using the figure of merit. During a diagnostic mode, the device collects impedance data using the selected electrode configuration. In one example, the figure of merit includes a ratio of a cardiac stroke amplitude and a respiration amplitude. Other examples of the figure of merit are also described.

Abstract: One embodiment of the present invention relates to an implantable medical device (“IMD”) that can be programmed from one operational mode to another operational mode when in the presence of electro-magnetic interference (“EMI”). In accordance with this particular embodiment, the IMD includes a communication interface for receiving communication signals from an external device, such as a command to switch the IMD from a first operation mode to a second operation mode. The IMD further includes a processor in electrical communication with the communication interface, which is operable to switch or reprogram the IMD from the first operation mode to the second operation mode upon receiving a command to do so. In addition, the IMD includes a timer operable to measure a time period from when the processor switches the IMD to the second operation mode.

Abstract: Techniques are provided for use with a pacemaker or other implantable medical device capable of sensing electrical signals along a set of programmable sensing vectors. In one example, electrical cardiac signals are sensed within a patient using a primary sensing vector connected to a primary sensing channel for use in controlling the delivery of therapy. If the device detects a significant drop in key signal parameters such as peak signal amplitude or slew rate, an assessment is made whether an alternate sensing vector provides improved cardiac signal sensing. During the assessment, the device can continue to sense signals along the primary channel for the purposes of controlling therapy while alternate vectors are assessed in the background. If it is determined that an alternate sensing vector provides improved cardiac signal sensing, the primary sensing channel can be switched to the alternate sensing vector for use in controlling further therapy.

Abstract: Systems and methods are provided for graphically configuring leads for a medical device. According to one aspect, the system generally comprises a medical device and a processing device, such as a programmer or computer, adapted to be in communication with the medical device. The medical device has at least one lead with at least one electrode in a configuration that can be changed using the processing device. The processing device provides a graphical display of the configuration, including a representative image of a proposed electrical signal to be applied by the medical device between the at least one electrode of the medical device and at least one other electrode before the medical device applies the electrical signal between the at least one electrode and the at least one other electrode. In one embodiment, the graphical display graphically represents the lead(s), the electrode(s), a pulse polarity, and a vector.

Abstract: A method for diagnosing an implantable cardiac device including a plurality of implanted leads may include: monitoring a plurality of parameters associated with the plurality of implanted leads; detecting a change in one of the parameters; evaluating at least one of the other parameters upon detection of the change; and diagnosing a problem with the implantable cardiac device based on the detected change and the evaluation. A system for diagnosing an implantable cardiac device including a plurality of implanted leads may include an implantable pacing device and a processor. The processor may be configured to: monitor a plurality of parameters associated with the plurality of implanted leads; detect a change in one of the parameters; evaluating at least one of the other parameters upon detection of the change; and diagnose a problem with the implantable cardiac device based on the detected change and the evaluation.

Abstract: In general, the disclosure describes techniques for storing data corresponding to sensed high-rate non-sustained episodes that occur close in time to detection of a lead integrity condition. A method comprises detecting a first high-rate non-sustained episode, activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the first episode, and storing data associated with the first episode in an episode log in response to activating the data storage operation. Another method comprises detecting a lead integrity condition, and activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the condition.

Abstract: An implantable cardiac device that detects and protects against strong magnetic fields produced by MRI equipment is disclosed. The device has a magnetic field sensor for detecting the presence of a relatively weak static magnetic field (102, 110, 118, 122) of a level equivalent to that of a permanent magnet in the vicinity of the device. The device is switched from a standard operating mode (100) where the nominal functions of the device are active, to a specific protected MRI mode (114, 116) in the presence of a magnetic static field of a level corresponding to that emitted by MRI equipment. The device further temporarily switches the device from the standard operating mode (100) to an MRI stand-by state (108) when a magnetic field is detected by the magnetic field sensor such that a subsequent detection of a magnetic field switches the device from an MRI stand-by state to the specific protected MRI mode.

Abstract: A method and device provide for determining capture in multiple chambers of a patient's heart using an electrode inserted into a coronary vein of the patient's heart. The coronary vein electrode is positioned adjacent to multiple heart chambers and is responsive to cardiac signals originating in the multiple chambers. The coronary vein electrode may be coupled to a single sense amplifier to detect the cardiac signals. Pace pulses may be applied to multiple heart chambers simultaneously or according to a phased timing sequence. Cardiac signals responsive to the pace pulses sensed using the coronary vein electrode may be used to verify capture in the multiple chambers of the heart.

Abstract: A device and method for delivering electrical stimulation to the heart in a manner which provides a protective effect against subsequent ischemia is disclosed. The protective effect is produced by configuring a cardiac pacing device to intermittently switch from a normal operating mode to a stress augmentation mode in which the spatial pattern of depolarization is varied to thereby subject a particular region or regions of the ventricular myocardium to increased mechanical stress.

Abstract: An implantable medical device (IMD) determines an effect of the disruptive energy field and adjusts one or more operating parameters of the IMD based on at least the determined effect. In some instances, the IMD may determine an actual effect of the disruptive energy field, such as a temperature change, impedance change, pacing or sensing threshold change, MRI-induced interference one pacing or sensing, or other actual effect. In other instances, the IMD may determine a predicted effect of the disruptive energy field based on one or more characteristics of the exposure. In any case, the IMD adjusts one or more parameters based on at least the determined effect.