Abstract: An example of a system comprises a cardiac pulse generator configured to generate cardiac paces to pace the heart, a sensor configured to sense a physiological signal for use in detecting pace-induced phrenic nerve stimulation (PS), a storage, and a phrenic nerve stimulation detector. The storage is configured for use to store patient-specific PS features for PS beats with a desirably large signal-to-noise ratio. The phrenic nerve stimulation detector may be configured to detect PS features for the patient by analyzing a PS beat with a desirably large signal-to-noise ratio induced using a pacing pulse with a large energy output and store patient-specific PS features in the storage, and use the patient-specific PS features stored in the memory to detect PS beats when the heart is paced heart using cardiac pacing pulses with a smaller energy output.

Abstract: The invention relates to a method and apparatus for diagnosis of conductor anomalies, such as insulation failures, in an implantable medical device, such as an implantable cardioverter defibrillator (ICD), a pacemaker, or a neurostimulator. Insulation failures are detected and localized by identifying changes in electrical fields via surface (skin) potentials. Small variations in potential are detected along the course of the electrode near the site of insulation failure.

Abstract: Systems and methods are described herein for determining whether anodal capture of the right ventricle is occurring when delivering left ventricular pacing with a cross-chamber pacing vector. The systems and methods may be measure cross-chamber sense times from left ventricular pacing and right ventricular pacing and compare the cross-chamber sense times to determine whether anodal capture of the right ventricle is occurring.

Abstract: An industrial machine that includes a dipper, a hoist drum, a wire rope connected between the hoist drum and the dipper, a hoist motor, a sensor, and a controller. The sensor generates a signal related to a number of wire wraps of the wire rope around the hoist drum, which is received by the controller. The controller determines, based on the signal from the sensor, the number of wire wraps around the hoist drum. If the controller determines that there are an insufficient number of dead wraps around the hoist drum, the controller sets one or more parameters of the hoist motor. The controller sets each of the one or more parameters of the hoist motor to a value that is lower than a normal operational value for the parameter.

Abstract: A cardiac resynchronization pacemaker and a method of adjusting the pacemaker. The method includes deriving a vectorcardiogram from implanted electrodes (D-VCG), analyzing the D-VCG, deriving optimal CRT pacing parameters from the analysis of the D-VCG, and adjusting the CRT pacemaker according to the derived parameters. The pacemaker may include a processor configured to perform the method.

Abstract: An exemplary method includes performing a capture threshold assessment using a bipolar electrode configuration, deciding if capture occurred for a maximum energy value of the capture threshold assessment and, if capture did not occur, then performing a lead impedance test for the lead associated with the bipolar electrode configuration. Such a test may aim to detect an insulation defect and/or a conductor defect. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Methods and systems for performing capture threshold tests are described. During an initialization procedure a capture detection interval and capture detection threshold are determined based on peak values of cardiac signals sensed following the supracapture threshold initialization pulses. Following initialization, a plurality of pacing pulses to the atrium are delivered and the peak values of the cardiac signals sensed following each of the plurality of pacing pulses are determined. The peak values are compared to the pacing artifact threshold and the capture detection threshold. A timing of each of the peak values is compared to the capture detection interval. For each pacing pulse, discrimination between a captured response, a noncaptured response, and a fusion response is based on the peak value and timing comparisons.

Abstract: Methods and systems for performing capture threshold tests are described. During an initialization procedure a capture detection interval and capture detection threshold are determined based on peak values of cardiac signals sensed following the supracapture threshold initialization pulses. Following initialization, a plurality of pacing pulses to the atrium are delivered and the peak values of the cardiac signals sensed following each of the plurality of pacing pulses are determined. The peak values are compared to the pacing artifact threshold and the capture detection threshold. A timing of each of the peak values is compared to the capture detection interval. For each pacing pulse, discrimination between a captured response, a noncaptured response, and a fusion response is based on the peak value and timing comparisons.

Abstract: Systems and methods are provided for evaluating an expected effectiveness of cardiac resynchronization therapy. Electrocardiogram (ECG) data is received as at least one ECG lead from a set of electrodes. A frequency spectrum representing the ECG data is generated via a Fourier transform. At least one predictor value is extracted from the calculated frequency spectrum. A fitness parameter, representing the expected effectiveness of cardiac resynchronization, is determined from at least the extracted predictor value.

Abstract: Techniques for determining whether one or more leads are not adequately connected to a patient, e.g., for ECG monitoring, are described. The techniques involve injection of an integrated signal (which includes a test signal) into one lead, and monitoring the driven lead and the response at the other leads, including the common mode and the difference between the other leads. These “lead-off” detection techniques may be provided by an external defibrillator that provides three-wire ECG monitoring. Techniques for determining a type of a cable coupled to a defibrillator are also described. The cable-type identification may allow a defibrillator to, for example, operate in either a three-wire ECG monitoring mode or a therapy mode, based on whether a three-wire ECG cable or a defibrillation cable is coupled to the defibrillator.

Abstract: An implantable medical device (IMD) automatically determines at least a portion of the parameters and, in some instances all of the parameters, of an exposure operating mode based on stored information regarding sensed physiological events or therapy provided over a predetermined period of time. The IMD may configure itself to operate in accordance with the automatically determined parameters of the exposure operating mode in response to detecting a disruptive energy field. Alternatively, the IMD may provide the automatically determined parameters of the exposure operating mode to a physician as suggested or recommended parameters for the exposure operating mode. In other instances, the automatically determined parameters may be compared to parameters received manually via telemetry and, if differences exist or occur, a physician or patient may be notified and/or the manual parameters may be overridden by the automatically determined parameters.

Abstract: A cardiac rhythm management system provides for cardiac pacing that is delivered to a target portion of conductive tissue in a heart, such as the His bundle. In various embodiments, the system is configured to verify capture of the target portion and provide for selective pacing of the target portion. In various embodiments, the system is configured to detect responses of the target portion and adjacent myocardial tissue to delivery of pacing pulses and use an outcome of the detection to verify selective capture of the target portion (i.e., without directly exciting the adjacent myocardial tissue.

Abstract: Generally, the disclosure is directed one or more methods or systems of cardiac pacing employing a right ventricular electrode and a plurality of left ventricular electrodes. Pacing using the right ventricular electrode and a first one of the left ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Computing a first degree of resynchronization based on a sum of differences of activation times and corresponding activation times. Pacing using the right ventricular electrode and a second one of the ventricular electrodes and measuring activation times at other ones of the left ventricular electrodes. Computing a second degree of resynchronization based on the sum of differences of activation times and corresponding activation times.

Abstract: A CRM system enhances intracardiac electrogram-based arrhythmia detection using a wireless electrocardiogram (ECG), which is a signal sensed with implantable electrodes and approximating a surface ECG. In one embodiment, an intracardiac electrogram allows for detection of an arrhythmia, and the wireless ECG allows for classification of the detected arrhythmia by locating its origin. In another embodiment, the wireless ECG is sensed as a substitute signal for the intracardiac electrogram when the sensing of the intracardiac electrogram becomes unreliable. In another embodiment, a cardiac signal needed for a particular purpose is selected from one or more intracardiac electrograms and one or more wireless ECGs based on a desirable signal quality. In another embodiment, intracardiac electrogram-based arrhythmia detection and wireless ECG-based arrhythmia detection confirm with each other before indicating a detection of arrhythmia of a certain type.

Abstract: An implantable medical system may include an implantable medical lead including at least one electrode and an implantable medical device. The implantable medical device comprises an electromagnetic interference (EMI) detection module that monitors for one or more particular characteristics of EMI. A control module is configured to control a therapy module to generate monophasic stimulation pulses while operating the IMD in a first operating mode. In response to detecting the condition indicative of the presence of EMI, the control module switches the IMD from the first operating mode to a second operating mode and generates at least one multiphasic stimulation pulses while operating the IMD in the second operating mode.

Abstract: Approaches for rate initialization and overdrive pacing used during capture threshold testing are described. Cardiac cycles are detected and the cardiac events of a cardiac chamber that occur during the cardiac cycles are monitored. The number of intrinsic beats in the cardiac events is counted. Initialization for a capture threshold test involves maintaining a pre-test pacing rate for the capture threshold test if the number of intrinsic beats in the cardiac events is less than a threshold. The pacing rate is increased for the capture threshold test if the number of intrinsic beats in the cardiac events is greater than the threshold.

Abstract: An implantable system acquires intracardiac impedance with an implantable lead system. In one implementation, the system generates frequency-rich, low energy, multi-phasic waveforms that provide a net-zero charge and a net-zero voltage. When applied to bodily tissues, current pulses or voltage pulses having the multi-phasic waveform provide increased specificity and sensitivity in probing tissue. The effects of the applied pulses are sensed as a corresponding waveform. The waveforms of the applied and sensed pulses can be integrated to obtain corresponding area values that represent the current and voltage across a spectrum of frequencies. These areas can be compared to obtain a reliable impedance value for the tissue. Frequency response, phase delay, and response to modulated pulse width can also be measured to determine a relative capacitance of the tissue, indicative of infarcted tissue, blood to tissue ratio, degree of edema, and other physiological parameters.

Abstract: Techniques for determining an attachment stability of leadless pacing device (LPD) implanted within a patient are described. For example, the LPD may detect one or more stability metrics from one or more electrodes of the LPD and/or an activity sensor within the LPD. Based on one or more of these stability metrics, e.g., a mechanical motion of the LPD, a stability module within the LPD may determine the attachment stability of the LPD within the patient. If the attachment stability is insufficient to provide efficacious therapy or indicates at least partial dislodgement of the LPD from tissue, the LPD may wirelessly transmit stability information to an external device. In some examples, the LPD may be implanted within a chamber of the heart.

Abstract: Various embodiments of the present invention are directed to, or are for use with, an implantable system including a lead having multiple electrodes implantable in a patient's left ventricular (LV) chamber. In accordance with an embodiment, the patient's LV chamber is paced at first and second sites within the LV chamber using a programmed LV1-LV2 delay, wherein the LV1-LV2 delay is a programmed delay between when first and second pacing pulses are to be delivered respectively at the first and second sites within the LV chamber. Evoked responses to the first and second pacing pulses are monitored for, and one or more LV pacing parameter is/are adjusted and/or one or more backup pulse is/are delivered based on results of the monitoring.

Abstract: An implantable medical system may include an implantable medical lead including at least one electrode and an implantable medical device. The implantable medical device comprises an electromagnetic interference (EMI) detection module that monitors for one or more particular characteristics of EMI. A control module is configured to control a therapy module to generate single stimulation pulses while operating the IMD in a first operating mode. In response to detecting the condition indicative of the presence of EMI, the control module switches the IMD from the first operating mode to a second operating mode and generates at least one group of two or more stimulation pulses in close proximity to one another in place of a single stimulation pulse while operating the IMD in the second operating mode.

Abstract: An implantable system includes terminals, a pulse generator, a sensing circuit, separate signal processing channels, and first, second and third multiplexers. The terminals are connected to electrodes via conductors of leads. Different subsets of the electrodes are used to define different electrical pulse delivery vectors, and different subsets of the electrodes are used to define different sensing vectors. The pulse generator produces electrical pulses, and the sensing circuit senses a signal indicative of an impedance associated with a selected sensing vector. The first multiplexer selectively connects outputs of the pulse generator to a selected one of the different electrical pulse delivery vectors at a time. The second multiplexer selectively connect inputs of the sensing circuit to a selected one of the different sensing vectors at a time. The third multiplexer selectively connects an output of the sensing circuit to one of the plurality of separate signal processing channels at a time.

Abstract: Systems and methods for stimulation of neurological tissue apply a stimulation waveform that is derived by a developed genetic algorithm (GA), which may be coupled to a computational model of extracellular stimulation of a mammalian myelinated axon. The waveform is optimized for energy efficiency.

Abstract: A physiological sense amplifier achieves fast recovery times following receipt of a large voltage, such as when a defibrillation pulse is delivered, without blanking. The recovery time may be less than one millisecond when polarization of surrounding tissue or the housing of the device is not present. The sense amplifier uses a feedback network to clamp the input voltage to a gain amplifier at a predetermined value when a predetermined threshold value is exceeded.

Abstract: Cardiac anodal electrostimulation detection systems and methods are described, such as for distinguishing between cathodal-only capture and at least partially anodal capture (e.g., combined anodal and cathodal capture, or between two anodes of which only one captures nearby cardiac tissue, etc.).

Abstract: In general, the disclosure relates to techniques for providing a combination of stored diagnostic information, including impedance trend data, into one displayable report that may be used to diagnose a possible condition with an implantable medical electrode lead. One example device includes a processor that is configured to obtain impedance trend data for an electrical path, the electrical path comprising a plurality of electrodes, and to obtain additional diagnostic data that is associated with the electrical path, the additional diagnostic data being distinct from the impedance trend data. The device is further configured to combine both the impedance trend data and the additional diagnostic data into a displayable report that indicates whether there is a possible condition with the electrical path. The additional diagnostic data may include non-sustained episode data, sensing integrity data, pacing threshold, and/or electrogram data (such as P-wave amplitude and/or R-wave amplitude data).

Abstract: Cardiac resynchronization therapy (CRT) delivered to a heart of a patient may be adjusted based on detection of a surrogate indication of the intrinsic atrioventricular conduction of the heart. In some examples, the surrogate indication is determined to be a sense event of the first depolarizing ventricle of the heart within a predetermined period of time following the delivery of a fusion pacing stimulus to the later depolarizing ventricle. In some examples, the CRT is switched from a fusion pacing configuration to a biventricular pacing configuration if the surrogate indication is not detected, and the CRT is maintained in a fusion pacing configuration if the surrogate indication is detected.

Abstract: Various techniques are disclosed for quickly and efficiently determining cardiac pacing vectors that minimize phrenic nerve stimulation.

Abstract: A method and system for selecting at least one left ventricular (LV) pacing site for an implantable medical device equipped for cardiac stimulus pacing using a multi-pole LV lead are provided. The method and system include sensing LV activation events at multiple LV sensing sites. The arrival times of the LV activation events for corresponding LV sensing sites are measured. The method and system further include calculating differences between the arrival times for combinations of the LV sensing sites to obtain inter-site arrival delays between the combinations of the LV sensing sites. When at least one of the inter-site arrival delays exceeds a threshold, the method and system include designating the LV sensing site from the corresponding combination that has a later arrival time as a first LV pacing site from which to deliver LV pacing pulses using the implantable medical device.

Abstract: In an example, a system includes a cardiac pulse generator configured to generate cardiac paces to pace the heart, a sensor configured to sense a physiological signal for use in detecting pace-induced phrenic nerve stimulation where the pace-induced phrenic nerve stimulation is phrenic nerve stimulation induced by electrical cardiac pace signals, and a phrenic nerve stimulation detector configured to analyze the sensed physiological signal to detect PS beats where the PS beats are cardiac paces that induce phrenic nerve stimulation. The detector may be configured to correlate signal data for sensed beat signals to a PS template to detect PS beats, or may be configured to analyze morphological features of sensed beat signals to detect PS beats, or may be configured to detect PS beats using a combination that both correlates signal data for sensed beat signals to a PS template and analyzes morphological features of sensed beat signals.

Abstract: An implantable medical device includes a sensor configured to generate an endocardial acceleration (EA) signal representative of activity of a patient's heart. The device further includes one or more circuits configured to identify within the EA signal at least one EA signal component corresponding to at least one peak of endocardial acceleration, and extract from the at least one EA signal component at least two characteristic parameters. The one or more circuits are further configured to generate a composite index based on a combination of the at least two characteristic parameters, determine a plurality of values of the composite index for a plurality of pacing configurations, and select a current pacing configuration from among the plurality of pacing configurations based on the plurality of values of the composite index.

Abstract: A medical device lead includes a lead body having a proximal end and a distal end. The proximal end is configured for connection to a pulse generator. One or more electrodes are at a distal end of the lead body, and a lead conductor extends through the lead body and is electrically coupled to at least one of the one or more electrodes. The conductor is configured to deliver electrical signals between the proximal end and the at least one of the one or more electrodes. A sacrificial conductor extends through the lead body adjacent to lead conductor and is configured to fail at a lower stress than the lead conductor.

Abstract: A medical device system performs a method for determining pacing threshold data. Signals are received from a cardiac capture sensor and a phrenic nerve stimulation sensor. A cardiac capture threshold is determined from the cardiac capture sensor signal and a phrenic nerve stimulation threshold is determined from the phrenic nerve stimulation sensor signal for multiple pacing electrode vectors.

Abstract: An improved technique is described for dealing with the detection of fusion beats when capture verification is performed by a cardiac pacing device such as during a capture threshold determination procedure. Schemes for classifying heart beats may misclassify beats as fusion beats due to feature/morphology changes in the test electrogram waveform that may occur even when capture is achieved.

Abstract: Performing a capture test on a stimulated cardiac cycle based on the analysis of a cardiac vectogram using an active medical device including circuits and control logic for delivering electrical stimulation pulses to a heart chamber; collecting electrical activity of the heart chamber and producing two distinct temporal components (Vbip, Vuni) from two distinct intracardiac electrogram EGM signals from the heart chamber. The capture test detects an occurrence of a depolarization wave induced by the stimulation of the heart chamber, and determines a two-dimensional non-temporal characteristic (VGM) representative of the stimulated cardiac cycle, from the variation of one of the temporal components (Vuni) versus the other temporal component (Vbip). A bi-dimensional analysis delivers at least one descriptor parameter of the two-dimensional non-temporal characteristic, and determines a presence or loss of a capture based on the at least one descriptor parameter.

Abstract: An implantable medical device can include a therapy circuit coupled to a therapy delivery terminal, the therapy circuit configured to generate a specified electrostimulation therapy for delivery to a tissue site via the therapy delivery terminal, and a measurement circuit for measuring at least two impedances of a first terminal combination including the therapy delivery terminal, the two impedances corresponding to at least two instances of excitation separated enough in time to capture an impedance artifact due at least in part to a motion of the heart, such as to determine an electrostimulation therapy lead status at least in part using the at least two impedances.

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: An apparatus comprises a control circuit that initiates a normal pacing mode for delivery of electrostimulation energy to the heart chamber. In response to an indication to initiate a threshold test, the control circuit determines an electrode configuration used to deliver the electrostimulation energy in the normal pacing mode, selects a first threshold test mode when a sensing electrode independent from the set of pacing electrodes is unavailable for the heart chamber, wherein a cardiac activity signal is sensed using a set of sensing electrodes that includes an electrode common to the set of pacing electrodes, and selects a second threshold test mode when a sensing electrode independent from the set of pacing electrodes is available for the heart chamber, wherein the cardiac activity signal is sensed using a set of sensing electrodes that excludes an electrode common to the set of pacing electrodes.

Abstract: An exemplary method includes performing a capture threshold assessment using a bipolar electrode configuration, deciding if capture occurred for a maximum energy value of the capture threshold assessment and, if capture did not occur, then performing a lead impedance test for the lead associated with the bipolar electrode configuration. Such a test may aim to detect an insulation defect and/or a conductor defect. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An implantable medical device capable of sensing cardiac signals and delivering cardiac electrical stimulation therapies is enabled to detect a short circuit condition. In one embodiment, a cardiac signal is sensed by a sensing module coupled to electrodes. A controller identifies signal events in response to the cardiac signal and detects a short circuit condition in response to at least one of the signal events having an amplitude crossing a short circuit detection threshold and a maximum of two signal events crossing the short circuit detection threshold occurring between two adjacent events having amplitudes not crossing the short circuit detection threshold. In one embodiment, the signal events are identified from a differential signal determined from the sensed cardiac signal.

Abstract: Approaches for selecting an electrode combination of multi-electrode pacing devices are described. Electrode combination parameters that support cardiac function consistent with a prescribed therapy are evaluated for each of a plurality of electrode combinations. Electrode combination parameters that do not support cardiac function are evaluated for each of the plurality of electrode combinations. An order is determined for the electrode combinations based on the parameter evaluations. An electrode combination is selected based on the order, and therapy is delivered using the selected electrode combination.

Abstract: Methods and device for determining a pacing vector for delivering an electrostimulation therapy are described. An implantable medical device may be configured to determine an anode capture threshold and a cathode capture threshold for a first anode and cathode pair of electrodes, switch a polarity of the first anode and cathode pair of electrodes, and determine an anode capture threshold and a cathode capture threshold for the first anode and cathode pair of electrodes having the switched polarity. The implantable medical device may be further configured to compare a cathodal capture threshold for the anode and cathode pair having the switched polarity to the anodal capture threshold of the first anode and cathode pair of electrodes and select either an anode or a cathode for delivering an electrostimulation therapy based at least in part on the comparison. Other methods and systems are also contemplated and described.

Abstract: Techniques are provided for use by an implantable medical device for assessing and controlling concurrent anodal/cathodal capture. In one example, the device delivers bipolar pacing stimulus while sensing a bipolar intracardiac electrogram (IEGM) and while adjusting a magnitude of the pacing stimulus. The device analyzes the bipolar IEGM signals to detect an indication of activation representative of concurrent anodal and cathodal capture. Preferably, the pulse magnitude is set relative to the anodal/cathodal capture threshold based upon clinician programming in response to the needs of the patient. In this manner, concurrent anodal and cathodal capture can be selectively activated or deactivated based on clinician instructions received from a device programmer or other external programming device. Techniques exploiting both bipolar and unipolar IEGM signals to assess and control concurrent anodal/cathodal capture are also described.

Abstract: Methods and/or devices may be configured to track effectiveness of pacing therapy by monitoring two or more electrical vectors of the patient's heart during pacing therapy and analyzing at least one feature of a morphological waveform within each of the two or more electrical vectors.

Abstract: Methods, systems and devices described herein can be used for automatically adjusting one or more cardiac resynchronization therapy (CRT) pacing parameters (and more generally stimulation parameters), to achieve a long term reduction in left ventricular (LV) diastolic pressure (and more generally, preload) of a heart failure (HF) patient. A reduction in LV diastolic pressure is indicative of a reduction in preload (the force of blood the fills the left ventricle), which is typically indicative of an improvement in a patient's HF condition. In accordance with certain embodiments, when a set of stimulation parameters is tested, the set is tested for a period that is sufficiently long enough to allow the patient's compensatory mechanisms to react to the set of stimulation parameters and achieve a substantially steady-state LV diastolic pressure corresponding to the using the set of stimulation parameters.

Abstract: The disclosure describes implantable medical systems that respond to occurrence of a lead-related condition by utilizing an elongated coil electrode in defining an alternative pacing therapy vector to maintain optimal drain of an IMD power supply. An exemplary system includes a medical electrical lead having an elongated electrode and an improved sensing and therapy delivery circuitry to provide the alternative pacing therapy vector responsive to the lead-related conditions. The system includes circuitry for recognition of the lead type in order to respond to the occurrence of the lead-related condition.

Abstract: Approaches for characterizing a phrenic stimulation threshold, a cardiac capture threshold, a maximum device parameter, and a minimum device parameter are described. A plurality of cardiac pacing pulses can be delivered by using a cardiac pacing device, a pacing parameter of the plurality of cardiac pacing pulses being changed between delivery of at least some of the pulses. One or more sensor signals can be evaluated to detect stimulation of the phrenic nerve by one or more of the plurality of cardiac pacing pluses. The evaluation of the one or more sensor signals and the pacing parameter can be compared to determine if a phrenic stimulation threshold is at least one of higher than a maximum device parameter and lower than a minimum device parameter.

Abstract: A medical device and associated method for monitoring a patient's heart rhythm sensing a cardiac signal determine whether a cardiac signal is noise corrupted by obtaining cardiac signal pulses and generating a pulse amplitude threshold in response to the plurality of signal pulses. The number of signal sample points exceeding the pulse amplitude threshold in each of the of signal pulses is computed. The cardiac signal is determined to be noise corrupted or non-corrupted in response to the computed number of signal sample points.

Abstract: Techniques are provided for use by implantable medical devices such as cardiac resynchronization therapy (CRT) devices for detecting pulmonary edema based on transthoracic impedance sensed using cardiac pacing/sensing leads, wherein detection can be performed while lead maturation occurs. Briefly, the implantable device determines whether the leads are within an initial post-implant interval following implant during which lead maturation generally occurs. The device then detects pulmonary edema or related medical conditions within the patient based on transthoracic impedance using a set of detection parameters adjusted for use during the post-implant interval. Thus, rather than “blanking” impedance data during lead maturation, the device instead detects and processes impedance during this period to identify possible episodes of pulmonary edema so that appropriate measures can be undertaken, such as delivery of warnings or titration of appropriate medications.

Abstract: The disclosure relates to systems and methods for cardiac rhythm management. In some cases, a system may include a pulse generator for generating pacing pulses for stimulating a heart of a patient; a memory; and a sensor configured to sense a response to a unwanted stimulation and to produce a corresponding sensor signal. A processing circuit may receive the sensor signal for a time after one or more pacing pulses, and may derive a time-frequency representation of the sensor signal based on the received sensor signal. The processing circuit may use the time-frequency representation of the sensor signal to help identify unwanted stimulation. Once unwanted stimulation is detected, the processing circuit may change the pacing pulses to help reduce or eliminate the unwanted stimulation.

Abstract: A differential or relative measurement between an orthogonal measurement vector and another measurement vector can be used to determine the location where fluid accumulation is occurring or the local change in such fluid accumulation. This can help diagnose or treat infection or hematoma or seroma at a pocket of an implanted cardiac rhythm management device, other implanted medical device, or prosthesis. It can also help diagnose or treat pulmonary edema, pneumonia, pulmonary congestion, pericardial effusion, pericarditis, pleural effusion, hemodilution, or another physiological condition.