Abstract: A medical device for characterizing the cardiac status of a patient equipped with a bi-ventricular pacing active implant device. The implant collects an endocardiac acceleration signal and searches for an optimal pacing configuration. This latter tests a plurality of different pacing configurations and delivers for each tested configuration parameters derived from the endocardiac acceleration peak (PEA). The device derives a patient clinical status from those parameters, the indication being representative of the patient's response to the cardiac resynchronization therapy. Those parameters include: the possibility to automatically get or not a valid optimal AV Delay among all the biventricular pacing configurations; a factor indicating the character sigmoid of the PEA/AVD characteristic; the average value of the PEA for the various configurations; and the PEA signal/noise ratio.

Abstract: Methods for identifying and extracting heart depolarization and repolarization in a paced heart. Certain methods also include identifying and analyzing particular features of at least one pacing spike and QRS waveform for heart beat characterization. These features may include signal changing speed and signal time interval (distance) of pacing spikes and QRS depolarization when pacing excitation is initialized.

Abstract: A troubleshooting method can identify potential sources of noise emanating from an implanted portion of a medical system. The method, which may be carried out by the system, for example, according to pre-programmed instructions, includes a step of collecting at least one EGM sample from a sensing pair of electrodes, and an EGM sample from each of a plurality of recording pairs of electrodes. The sensing pair may be formed by first and second electrodes of an implanted lead, and the plurality of recording pairs include pairs formed by each of the lead electrodes and an electrode of an implanted device. Following collection, the EGM samples from the recording pairs may be analyzed for the presence or absence of noise and, then, potential noise sources may be determined.

Abstract: A method for selecting a cardiac pacing site includes steps of: securing first and second electromagnetic receiver coils at first and second positions, respectively, along a heart wall; collecting a set of non-paced heart wall motion data from each of the coils secured at the corresponding positions; applying cardiac pacing stimulation at at least one first pacing site; collecting a first set of paced heart wall motion data from each of the secured coils; comparing the non-paced heart wall motion data to the first set of paced heart wall motion data; and determining, based on the comparing, whether to maintain pacing at the at least one first cardiac pacing site or to apply pacing stimulation at a second pacing site for collection of a second set of paced heart wall motion data. The at least one first pacing site may include a right ventricular site and a left ventricular site.

Abstract: Certain embodiments of the present invention disclose an electrostimulator, in particular an atrial cardiac pacemaker, comprising electrode connections which are connected to a stimulation unit for the delivery of stimulation pulses by way of the electrode connections, and a stimulation control unit which is connected to the stimulation unit and adapted to trigger the delivery of stimulation pulses and to determine the strength of the stimulation pulses and for that purpose to deliver a stimulation control signal to the stimulation unit, and a detection unit which is connected to the stimulation control unit and at least indirectly to the electrode connections and adapted to evaluate electrical potentials at the electrode connections and to detect intrinsic (natural, spontaneous) events.

Abstract: A method utilizing computer processing for detecting, within a cardiac cycle, the earliest onset of global, Q-onset, ventricular depolarization in the presence of an operating pacemaker. The method, in general terms, features (a) gathering a plurality of ECG-obtained QRS heart-cycles waveforms, (b) identifying and categorizing of evidences and specific timings therein of intrinsic Q-onset and pacemaker spike events, (c) looking in a single, selected QRS waveform, between specific, defined first and second time marks, for the most significant slope change appearing in that waveform, and (d) designating to be the correct Q-onset that event which immediately precedes that slope change.

Abstract: A system for monitoring drug dispensation and drug effects on physiological signals or implantable medical device (IMD) performance is provided. The system includes a drug dispenser adapted for telemetric communication with an IMD, an IMD capable of acquiring time-based physiological or device performance data, and a programmer/monitor for receiving and displaying IMD-acquired data and drug dispensation data. The system may further include a patient activator for transmitting signals indicative of symptoms experienced by a patient associated with a side-effect caused by a drug or a condition for which the drug has been prescribed to treat. In an associated method, a drug dispensation signal is generated upon activation of the drug dispenser. IMD-acquired data, drug dispensation data, and patient symptom data are retrieved by a programmer/monitor. IMD-acquired data is combined with or grouped according to drug dispensation data and displayed.

Abstract: In a method and an apparatus for creating hemodynamic sensor signal templates using an implantable medical device connectable to a patient heart activity of the patient is sensed in order to identify a paste or sensed sequence of events of a heart cycle. Hemodynamic sensor signals for consecutive heart cycles are sensed and the sensed hemodynamic sensor signals for consecutive heart cycles are stored. The sensed sensor signals are classified dependent on at least one predetermined heart event sequence condition. A template may be created using the classified sensor signals.

Abstract: Treating the physiological electric conduction of the heart includes methods that involve guiding an electrode to a location, near the His bundle of the heart, that is determined by pacing the heart and sensing signals in response thereto, and electrically bypassing a conduction abnormality of the heart by presenting extrinsic pacing signals to the location near the His bundle of the heart. The pacing electrode may then be fixed at the location, near the His bundle, to provide subsequent pacing of the heart such that the subsequent pacing exhibits electrical bypassing of the conduction abnormality.

Abstract: The present invention provides diverse methods and apparatus for in vivo monitoring, detecting and/or predicting potential failure modes or deleterious trends of chronically implanted medical electrical leads prior to actual failure of said leads. Certain embodiments of the invention involve applying a relatively increased data sampling rate at various time intervals (e.g., periodically, randomly, and/or manually-triggered and the like) prior to actual detection of a deleterious trend, to thereby increase the probability of detecting one or more parameters indicative of a potential lead performance issue. At least some of the parameters are utilized because they are not typically reliably detected at relatively lower data sampling rates.

Abstract: Heart stimulating system for stimulating at least a ventricle of a heart including: stimulation pulse generator adapted to generate stimulation pulses and connected to a ventricular stimulation electrode for delivering stimulation pulses, atrial sensing stage connected to an electrode for picking up potentials inside an atrium and adapted to sense an excitation or contraction of atrial myocardium, ventricular sensing stage connected to an electrode for picking up potentials inside a ventricle and adapted to sense an excitation or contraction of ventricular myocardium, memory for AV-delay values, a control unit adapted to trigger said stimulation pulse generator to generate ventricular stimulation pulses timed based on AV-delay values stored in said memory and to acquire atrioventricular interval samples, and atrioventricular interval timing analyzing unit for receiving atrioventricular interval samples from said control unit and adapted to generate at least one histogram based on said atrioventricular interva

Abstract: This invention relates generally to systems and methods for optimizing the performance and minimizing complications related to implanted sensors, such as pressure sensors, for the purposes of detecting, diagnosing and treating cardiovascular disease in a medical patient. Systems and methods for anchoring implanted sensors to various body structures is also provided.

Abstract: Multi-chamber pacing may result in capture of one chamber, capture of multiple chambers, fusion, or non-capture. Approaches for detecting various capture conditions during multi-chamber pacing are described. Pacing pulses are delivered to left and right heart chambers during a cardiac cycle. A cardiac electrogram signal is sensed following the delivery of the pacing pulses. Left chamber capture only, right chamber capture only, and bi-chamber capture may be distinguished based on characteristics of the cardiac electrogram signal. Multi-chamber capture detection may be implemented using detection windows having dimensions of time and amplitude. The detection windows are associated with expected features, such as expected signal peaks, under a particular capture condition. The cardiac electrogram signal features are compared to detection windows to determine the capture condition.

Abstract: Implementing a subcutaneous medical electrode system involves positioning a number of electrode subsystems in relation to a heart so that noise cancellation provides an improved signal to noise ratio of the cardiac signal and/or to provide one electrode arrangement preferential for cardiac signals and another arrangement preferential for noise signals. One of the electrode subsystems so positioned may include one or more can electrodes located on a housing enclosing a medical device. The medical device may be configured to provide therapeutic, diagnostic, or monitoring functions, including, for example, cardiac arrhythmia therapy.

Abstract: Cardiac devices and methods using cardiac waveform clustering for template generation are described. A method of characterizing a cardiac response involves delivering pacing pulses to heart, the pulses having an energy greater than a capture threshold. Cardiac signals are sensed following the pulses. Cardiac signal characteristics, waveforms, and/or features are clustered into a plurality of clusters. A cardiac response template is formed using one or more of the plurality of clusters.

Abstract: A medical system comprises a plurality of electrodes; at least one sensor configured to output at least one signal based on at least one physiological parameter of a patient; and a processor. The processor is configured to control delivery of stimulation to the patient using a plurality of electrode configurations. Each of the electrode configurations comprises at least one of the plurality of electrodes. For each of the electrode configurations, the processor is configured to determine a first response of target tissue to the stimulation based on the signals, and a second response of non-target tissue to the stimulation based on the signals. The processor is also configured to select at least one of the electrode configurations for delivery of stimulation to the patient based on the first and second responses for the electrode configurations. As examples, the target tissue may be a left ventricle or vagus nerve.

Abstract: In an apparatus and a method for use in setting a sensing parameter of an implantable medical device (IMD) of a patient, cardiac data corresponding to a cardiac episode experienced by the patient is obtained from a sensing electrode associated with the IMD. At the time the cardiac data is obtained, the IMD is operated at a first setting of the sensing parameter. Based upon this cardiac data, a simulation is performed of cardiac event identification if the IMD were operated at a different setting of the sensing parameter. The simulated cardiac event identification performance of the IMD is then reported.

Abstract: A medical device known as a trial neuro stimulator with a diagnostics module to determine whether the therapy lead is operational for delivering stimulation therapy to improve operation in areas such as reliability and patient comfort is disclosed. The trial neuro stimulator is typically used to test the efficacy of neuro stimulation before implanting an implantable neuro stimulator in a patient. The trial neuro stimulator has a processor, memory, system reset, telemetry module, recharge module, power management module, power source, therapy module, therapy measurement module, and diagnostics module. The diagnostics module can be a lead sensor, a software detector using therapy lead measurements from the therapy measurement module, or, a combination of both the lead sensor and software detector to detect whether the therapy lead is operational. A method for diagnosing whether a therapy lead is operational is also disclosed.

Abstract: A cardiac therapy pulse delivery system includes a plurality of electrodes, an ECG signal processor circuit, and a pulse generator circuit. Each of the electrodes has at least one therapy element and at least one monitor element that are electrically insulated from one another. The ECG signal processor circuit is electrically coupled to each monitor element on each electrode and is operable to convert ECG signals detected by the monitor elements into ECG data. The cardiac pulse generator circuit is electrically coupled to each therapy element on each electrode and is operable to supply one or more cardiac therapy pulses thereto.

Abstract: An implantable heart stimulating device has a left ventricular coronary sinus electrode lead provided with a tip electrode, a right ventricular electrode lead provided with a ring electrode, and a pulse generator connected to the leads that applies stimulation pulses between the tip electrode and the ring electrode, with the tip electrode serving as the anode. A monitoring unit monitors for and detects anodal capture at the right ventricular ring electrode subsequent to a stimulation. If anodal capture is detected, either a threshold search is performed by varying the pulse width and/or pulse amplitude of stimulation pulses in order to identify stimulation pulse characteristics that avoid anodal capture at the ring electrode, or at least one further electrode is activated to function as an indifferent electrode together with the ring electrode, also in order to avoid anodal capture at the ring electrode.

Abstract: A method of assessing contractility of a cardiac muscle which has an activation parameter, the method comprising: (a) utilizing time correlated data pertaining to an activation parameter to produce a profile of said parameter; and (b) analyzing changes in said profile to generate an indication of contractility.

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: An apparatus, a method and a protocol for optimizing an implanted device in a candidate. The apparatus comprises a first sensor configured to sense a tracing signal, a transducer configured to capture an image of a region of interest, where the image is captured in synchronism with the tracing signal, and a determiner configured to determine a cardiac functional value based on the image and the tracing signal. A parameter of the implanted device is adjusted based on the cardiac functional value.

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: 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 delivering pulses 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, a catheter arrangement includes a fixation mechanism to attach the catheter arrangement to heart tissue, individually-addressable electrodes for providing pacing signals to the heart tissue, and an elongated structure that supports the fixation mechanism and the electrodes.

Abstract: Methods and systems are disclosed for determining whether a patient is a responder to cardiac resynchronization therapy. The beginning and ending of the intrinsic ventricular depolarization are determined through signals measured from one or more electrodes implanted in the patient's heart. An interval between the beginning and ending of the intrinsic ventricular depolarization is computed and is compared to a threshold. The threshold may be determined empirically. The pacing parameters of a heart stimulation device, such as a pacemaker, may then be configured, for example, by setting the paced atrio-ventricular delay based on whether the patient responds positively to cardiac resynchronization therapy.

Abstract: A method is disclosed that includes selecting an electrode configuration from a plurality of electrode configurations associated with electrodes of an implantable lead, sensing activity of the right ventricle and the left ventricle, determining an interval between sensed activity of the right ventricle and sensed activity of the left ventricle and determining whether the selected electrode configuration is suitable based at least in part on the interval. In one embodiment, an implantable device performs such a method to improve patient response to the CRT therapy, for example, by selecting a different electrode configuration if the current configuration is not suitable. Other exemplary methods, devices, systems, etc., are also disclosed.

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: Electrobiological stimulation is carried out transcranially by applying high frequency squarewave bursts exhibiting no d.c. term across the cranial region. Such stimulation is commenced employing ramp generators and positive and negative voltage converters which evolve the requisite baseform and burst frequencies having a voltage waveform which is square in nature. Both voltage and current are sensed and subjected to comparator logic in conjunction with predetermined thresholds and windows. Overcurrent detection and overvoltage detection is provided in hard wired fashion to assure rapid shutdown response. D.C offset detection is provided along with waveform balance tests to further assure the safety of the system. Diagnostic procedures as well as therapeutic procedures may be carried out with a system version which provides for the application of a stimulus in conjunction with safety monitoring and controller based development of stimulating waveforms, all of which exhibits no d.c. term.

Abstract: Methods and systems for delivering a pacing pulse to an atrium during a cardiac cycle. A retrograde P-wave may be identified during the cardiac cycle, indicative of sub-threshold atrial pacing. Delivery of the pacing pulse to the atrium may be adjusted in a subsequent cardiac cycle in response to identifying the retrograde P-wave. Adjusting delivery of the pacing pulse may involve initiating an atrial capture threshold test, temporarily increasing one or both of the pacing pulse amplitude and pulse width, and/or re-evaluating one or both of the pacing pulse amplitude and pulse width. Adjusting delivery of the pacing pulse may also involve altering the timing of a scheduled atrial capture threshold test. During an atrial capture threshold test, a retrograde P-wave template may be generated in response to atrial non-capture sensed during the atrial capture threshold test, and used to identify subsequent retrograde P-waves.

Abstract: An exemplary implantable device includes a microcontroller programmed to control delivery of cardiac therapy, a connector capable of making an electrical connection to an insulated conductor associated with an exposed electrode and a circuit connected to the conductor to measure an electrical half-cell potential of the electrode via the conductor and to signal the microcontroller if a defect occurs with respect to the insulated conductor. Such a defect may be an insulation defect and/or a conductor defect. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Various embodiments relate to a device to analyze an implantable neural stimulation system that includes an implantable neural stimulation lead for an implantable neural stimulator to be implanted into a patient. Various device embodiments comprise an external housing, a pacing circuit in the housing, and a sensing circuit in the housing. The pacing circuit is adapted to deliver a test neural stimulation signal. At least one test lead cable is adapted to electrically connect the pacing circuit and the implantable neural stimulation lead to enable the test neural stimulation signal to be delivered to a neural target through the test lead cable and the implantable neural stimulation lead. At least one physiological sensor is adapted to sense a physiological response to stimulation of the neural target. At least one sensor cable is adapted to electrically connect the sensing circuit and the at least one physiological sensor.

Abstract: A system and method for servicing a medical device, which provides for generation of a transfer function that correlates historical machine data with the health of the medical device. The transfer function may be validated and stored. The transfer function is automatically updated based on current machine data.

Abstract: Systolic timing intervals are measured in response to delivering pacing energy to a pacing site of a patient's heart. An estimate of a patient's acute response to cardiac resynchronization therapy (CRT) for the pacing site is determined using the measured systolic timing intervals. The estimate is compared to a threshold. The threshold preferably distinguishes between acute responsiveness and non-responsiveness to CRT for a patient population. An indication of acute responsiveness to CRT for the pacing site may be produced in response to the comparison.

Abstract: Methods and systems are disclosed for determining whether a patient is a responder to cardiac resynchronization therapy. The beginning and ending of the intrinsic ventricular depolarization are determined through signals measured from one or more electrodes implanted in the patient's heart. An interval between the beginning and ending of the intrinsic ventricular depolarization is computed and is compared to a threshold. The threshold may be determined empirically. The pacing parameters of a heart stimulation device, such as a pacemaker, may then be configured, for example, by setting the paced atrio-ventricular delay based on whether the patient responds positively to cardiac resynchronization therapy.

Abstract: A system for providing temporary therapy, such as cardiac resynchronization therapy, to a patient suffering a decompensation event. The system can include a device having an external module for generating electrical stimuli, a first lead coupled to the module and implanted into an atrial region of a patient's heart, and a second lead coupled to the module and implanted into a ventricular region of the patient's heart. The device can also include a storage module coupled to the external module to store data associated with physiological data measured by the device. The external module is configured to temporarily generate electrical stimuli that are delivered by at least one of the first and second leads to provide therapy cardiac resynchronization therapy to the heart. A network can be coupled to the device to allow data stored in the device to be downloaded through the network to a central repository.

Abstract: A method for delivering therapy in a medical device that includes a two-tiered approach of determining the presence of a lead-related condition, and determining, in response to a lead-related condition being present, the presence of oversensing. Deliver of therapy by the medical device is controlled in response to determining that both the lead-related condition and oversensing are present.

Abstract: In an embodiment, the invention includes a measurement system for measuring induced currents within an implantable medical device undergoing magnetic resonance imaging. The measurement system can include a resistor connected in series with a conductive loop and electronic circuitry configured to generate a signal representative of a voltage differential across the resistor. In some embodiments, the measurement system includes a fiber optic cable configured to transmit the signal away from the area subject to magnetic resonance imaging. In some embodiments, the measurement system includes a transmitter to wirelessly transmit the signal away from the area subject to magnetic resonance imaging. In an embodiment, the invention can include an implantable medical device including a measurement system for measuring induced currents. In an embodiment, the invention can include a method of measuring an induced current in an implantable medical device undergoing magnetic resonance imaging.

Abstract: A system for gathering, creating and utilizing signal-processed ECG and acoustic signals for assessing, via presenting a highly intuitive, multi-component, common-time-base, real-time output display of selected (1) timing, (2) relative timing, and (3) other significant heart-behavioral elements relevant to such an assessment, a patient's hemodynamic condition. The system offers an important option and capability for automatic, and/or manual, medical-treatment and/or pacemaker-control feedback, in real time, to improve a patient's hemodynamic status, with such a patient's resulting hemodynamic-behavioral/status changes caused by such feedback being viewable immediately in the invention's produced output display.

Abstract: Methods for estimating a remaining service life of an implantable medical device (IMD) battery employ calculations using a characteristic discharge model of the battery; the calculations require measurements of battery voltage and time. Systems employing the methods may include an external device coupled to the IMD, for example, via a telemetry communications link, wherein a first portion of a computer readable medium included in the IMD is programmed to provide instructions for the measurement, or tracking, of time and the measurement of battery voltage, and a second portion of the computer readable medium included in the external device is programmed to provide instructions for carrying out the calculations when the voltage and time data is transferred via telemetry from the IMD to the external device.

Abstract: An implantable medical device detects conditions such as a lead failure which may result in oversensing a physiologic condition. In response, the IMD automatically adjusts sensing thresholds, such as the number of intervals to detection in order to mitigate the effect of oversensing in the delivery of extraneous therapy.

Abstract: An implantable medical device (IMD) includes both evoked response and algorithmic based threshold testing methodologies. The leads used with the IMD are evaluated to determine whether they are high or low polarization. The evoked response methodology is only utilized if the leads are low polarization.

Abstract: An implantable medical device detects conditions such as a lead failure which may result in oversensing a physiologic condition. In response, the IMD automatically adjusts sensing thresholds, such as the number of intervals to detection in order to mitigate the effect of oversensing in the delivery of extraneous therapy.

Abstract: A method and apparatus for automatically identifying various types of cardiac and non-cardiac oversensing and automatically performing a corrective action to reduce the likelihood of oversensing is provided. EGM data, including time intervals between sensed and paced events and signal morphologies, are analyzed for patterns indicative of various types of oversensing, including oversensing of far-field R-waves, R-waves, T-waves, or noise associated with electromagnetic interference, non-cardiac myopotentials, a lead fracture, or a poor lead connection. Identification of oversensing and its suspected cause are reported so that corrective action may be taken. The corrective action may include, for example, adjusting sensing parameters such as blanking periods, decay constants, decay delays, threshold values, sensitivity values, electrode configurations and the like.

Abstract: An implantable medical device detects conditions such as a lead failure which may result in oversensing a physiologic condition. In response, the IMD automatically adjusts sensing thresholds, such as the number of intervals to detection in order to mitigate the effect of oversensing in the delivery of extraneous therapy.

Abstract: Methods and devices for classifying a cardiac response to pacing involve establishing a plurality of classification windows relative to and following a pacing pulse. One or more characteristics of a cardiac signal sensed following the pacing pulse are detected within one or more particular classification windows. The characteristics may be compared to one or more references. Classification of the cardiac response may be performed based on the comparison of the one or more characteristics to the one or more references and the particular classification windows in which the one or more characteristics are detected.

Abstract: Methods and devices for reducing phrenic nerve stimulation of cardiac pacing systems involve delivering a pacing pulse to a ventricle of a heart. A transthoracic impedance signal is sensed, and a deviation in the signal resulting from the pacing pulse may be used to determine phrenic nerve stimulation. Methods may further involve detecting the phrenic nerve stimulation from the pacing pulse by delivering two or more pacing pulse to the ventricle of the heart, and determining a temporal relationship. A pacing vector may be selected from the two or more vectors that effects cardiac capture and reduces the phrenic nerve stimulation. A pacing voltage and/or pulse width may be selected that provides cardiac capture and reduces the phrenic nerve stimulation. In other embodiments, a pacing pulse width and a pacing voltage may be selected from a patient's strength-duration curve that effects cardiac capture and reduces the phrenic nerve stimulation.

Abstract: The implantable cardiac treatment system of the present invention is capable of choosing the most appropriate electrode vector to sense within a particular patient. In certain embodiments, the implantable cardiac treatment system determines the most appropriate electrode vector for continuous sensing based on which electrode vector results in the greatest signal amplitude, or some other useful metric such as signal-to-noise ratio (SNR). The electrode vector possessing the highest quality as measured using the metric is then set as the default electrode vector for sensing. Additionally, in certain embodiments of the present invention, a next alternative electrode vector is selected based on being generally orthogonal to the default electrode vector. In yet other embodiments of the present invention, the next alternative electrode vector is selected based on possessing the next highest quality metric after the default electrode vector.

Abstract: Methods and devices of cardiac electrode placement involve locating electrodes on a thorax of a patient. Surface pacing levels are determined relative to a pacing limit. Surface electrode locations are selected or rejected based on the level being within a limit. Electrodes may be relocated to new locations, and new surface pacing levels determined, until a new surface pacing level falls within the pacing limit. Selecting or rejecting electrode locations involves selecting locations suitable for implantation of subcutaneous cardiac electrodes and implanting at the selected locations.

Abstract: A heart stimulator provides a reliable automatic capture threshold search feature. A stimulation pulse generator is connected to at least a ventricular stimulation electrode for delivering electric stimulation pulses to at least the ventricle of the heart. The stimulation pulses generated have a strength depending on a control signal. A sensing stage is connected to an electrode for picking up electric potentials inside at least said ventricle of a heart and a control unit connected to the sensing stage and to the stimulation pulse generator determines points of time for scheduling stimulation pulses, to trigger the stimulation pulse generator so as to deliver a stimulation pulse when scheduled and to put out control signals for controlling the strength of the stimulation pulse. The control unit is further adapted to perform a capture analysis which may take into account extraordinary events.