Patent application number | Description | Published |
20080234770 | Cardiac rhythm template generation system and method - A method and system provides for generating a snapshot representative of one beat of a patient's normal cardiac rhythm. Cardiac rate channel signals and shock channel signals are sensed. A fiducial point is determined for a predefined number of the cardiac rate channel signals. A predefined number of the shock channel signals are aligned using the fiducial point. A template is generated using the aligned shock channel signals, whereby the template is representative of one of the patient's normal supra-ventricular conducted cardiac beats. The template is updated on a periodic basis. | 09-25-2008 |
20080243201 | PACER WITH COMBINED DEFIBRILLATOR TAILORED FOR BRADYCARDIA PATIENTS - A combination pacer/defibrillator is tailored for bradycardia patients. In one example, its shock-delivery specificity exceeds its sensitivity to shockable ventricular tachyarrhythmias. In another example, its specificity exceeds 95%, or 99%, or even 99.5%. Sensitivity is programmed to a high desired sensitivity value, but only if it can be done without decreasing the specificity below the desired specificity threshold value. This can be conceptualized as “avoiding at all costs” delivering false shocks, even at the expense of failing to deliver a shock to a treatable ventricular tachyarrhythmia. Specificity enhancements include, among other things, inhibiting shock delivery when the patient is breathing or not supine, using multiple channels or a high rate VT/VF detection threshold. The present pacer/defibrillator device could potentially save the lives of bradyarrhythmia patients who are not presently clinically indicated for a defibrillator/pacer, but who have an increased risk of sudden cardiac death due to one or more risk factors. | 10-02-2008 |
20080288009 | SELF-ADJUSTING ECG MORPHOLOGICAL FEATURE CORRELATION THRESHOLD - An apparatus comprising an implantable cardiac signal sensing circuit configured for sensing an intrinsic cardiac signal, a memory to store a template of a morphology of normal atrial-ventricular conduction, and a controller that includes a tachyarrhythmia detection circuit and a correlation circuit. The tachyarrhythmia detection circuit is configured for detecting a rhythm with elevated ventricular rate using the sensed intrinsic cardiac signal. The correlation circuit is configured for iteratively calculating a correlation between the sensed intrinsic cardiac signal and the template, and comparing the calculated correlation to a variable correlation threshold to determine whether the detected rhythm correlates to the template. The apparatus also includes a therapy circuit configured for inhibiting a ventricular tachycardia therapy when the detected rhythm correlates to the template. Other apparatuses and methods are described. | 11-20-2008 |
20090043347 | Method and system for characterizing supraventricular rhythm during cardiac pacing - A method and system for generating a characterization of one beat of a patient's supraventricular rhythm (SVR) involves performing such characterization while the heart is being paced. During SVR characterization, various pacing parameters are modified and the patient's supraventricular rhythm is characterized while the pacing parameters are modified. The SVR characterization process is effective in single and multiple chamber pacing modes. | 02-12-2009 |
20090099616 | METHOD AND APPARATUS FOR CONCURRENT ATRIO-VENTRICULAR ANTI-TACHYCARDIA PACING - An implantable medical device delivers anti-tachyarrhythmia therapies including anti-tachycardia pacing (ATP). If a detected tachyarrhythmia is classified as a type suitable for treatment using ATP, the implantable medical device selects one of an atrial ATP (A-ATP) mode, a ventricular ATP (V-ATP) mode, and a concurrent atrio-ventricular ATP (concurrent AV-ATP) mode according to the characteristics of the detected tachyarrhythmia. The concurrent ATP mode is an ATP mode during which the atrial pacing pulses and the ventricular pacing pulses are delivered concurrently. In one embodiment, the concurrent AV-ATP mode includes a synchronized atrio-ventricular ATP (synchronized AV-ATP) mode during which atrial and ventricular pacing pulses are delivered synchronously and an independent atrio-ventricular ATP (independent AV-ATP) mode during which atrial and ventricular pacing pulses are delivered concurrently but timed independently. | 04-16-2009 |
20090216289 | CARDIAC RHYTHM MANAGEMENT SYSTEMS AND METHODS USING MULTIPLE MORPHOLOGY TEMPLATES FOR DISCRIMINATING BETWEEN RHYTHMS - This document describes systems, devices, and methods that use multiple morphology templates for discriminating between rhythms, such as supraventricular tachyarrhythmias (SVTs) and ventricular tachyarrhythmias (VTs), for delivering a countershock in response to a VT episode, but withholding delivery of such a countershock in response to an SVT episode. In certain examples, the particular morphology used for storing morphological features is selected at least in part using a sensor-indicated activity level of a subject, or a metabolic need of the subject. | 08-27-2009 |
20090222054 | Method and System for Characterizing a Representative Cardiac Beat Using Multiple Templates - The present invention provides a method and system for characterizing one beat of a patient's supraventricular rhythm. A plurality of templates is provided and updated using a plurality of qualified beats. Updating occurs by temporally aligning the shock channel waveforms of the template beats using rate channel fiducial points. The template beats are combined by point-by-point addition of the shock channel waveforms. The resultant updated template characterizes one of the patient's supraventricular conducted cardiac beats. | 09-03-2009 |
20090292332 | METHOD AND APPARATUS FOR MORPHOLOGY-BASED ARRHYTHMIA CLASSIFICATION USING CARDIAC AND OTHER PHYSIOLOGICAL SIGNALS - A tachyarrhythmia detection and classification system classifies tachyarrhythmias based on an analysis of morphological features of a cardiac signal enhanced by using one or more physiological parameters indicative of hemodynamic stability and/or activity level. The tachyarrhythmia detection and classification system computes a measure of similarity between an arrhythmic waveform of the cardiac signal a template waveform for that cardiac signal, such as a correlation coefficient representative of the correlation between morphological features of the arrhythmic waveform and morphological features of the template waveform. A detected tachyarrhythmia episode is classified by comparing the measure of similarity to a threshold that is dynamically adjusted using the one or more physiological parameters. | 11-26-2009 |
20090299425 | Atrial Tachyarrhythmia Detection Using Selected Atrial Intervals - Methods and systems are directed to detecting atrial tachyarrhythmia. A plurality of A-A intervals is detected. The detected A-A intervals are selected and used to detect atrial tachyarrhythmia. Selecting A-A intervals may be based on determining that A-A intervals are qualified. Qualified A-A intervals may be determined if a duration of the particular A-A interval falls outside a predetermined duration range, for example. Qualified A-A intervals may also be determined based on events occurring between consecutively sensed atrial events of the particular A-A interval, and whether the duration of the particular A-A interval falls within the predetermined duration range, for example. | 12-03-2009 |
20090299426 | Synchronized Ventricular Pacing to Promote Atrial Sensing - Methods and systems are described that involve synchronized ventricular pacing that promotes sensing of atrial events. The atrioventricular pacing delay is modified based on characteristics of previously sensed atrial events. The modified AV delay is implemented relative to a first atrial event. A second AV delay is implemented relative to a second atrial event if the second atrial event is sensed during the modified AV delay. A ventricular pacing pulse is delivered following the second AV delay. | 12-03-2009 |
20090306486 | SENSING VECTOR CONFIGURATION IN ICD TO ASSIST ARRHYTHMIA DETECTION AND ANNOTATION - An apparatus comprises an implantable cardiac signal sensing circuit, configured to provide a sensed near-field depolarization signal from a ventricle and to provide a sensed a far-field intrinsic atrial signal using a far-field atrial sensing channel, and a controller circuit communicatively coupled to the cardiac signal sensing circuit. The controller circuit includes a P-wave detection module configured to detect an atrial depolarization in the sensed far-field intrinsic atrial signal and a tachyarrhythmia detection module configured to detect an episode of tachyarrhythmia using the sensed near-field depolarization signal and to determine whether the tachyarrhythmia episode is indicative of supraventricular tachycardia (SVT) using the detected atrial depolarization and the sensed near-field depolarization signal. | 12-10-2009 |
20090312813 | Method and Device for Determination of Arrhythmia Rate Zone Thresholds - Approaches for determining threshold values for one or more arrhythmia rate zones and/or the number of rate zones are described. A probability function for heart rate is determined using collected and measured heart rate values. One or more heart rate probability values are selected. Thresholds for arrhythmia rate zones are determined from the probability function based on the selected probability values. Determining the rate zone thresholds may involve determining a threshold for a lower rate limit and/or determining one or more tachyarrhythmia rate zone thresholds. The number of rate zones may also be determined based on the probability function. | 12-17-2009 |
20100057152 | SUSTAINING VENTRICULAR TACHYCARDIA DETECTION - An apparatus comprises an implantable ventricular depolarization sensing circuit configured to provide a sensed ventricular depolarization signal, a timer circuit configured to provide a ventricular time interval between ventricular depolarizations, and a controller circuit communicatively coupled to the ventricular depolarization sensing circuit and the timer circuit. The controller circuit includes a ventricular tachycardia (VT) detection circuit configured to declare an episode of VT when a number of accelerated beats are detected, calculate a hysteresis VT detection threshold interval, and deem whether the episode of VT persists using the hysteresis VT detection threshold interval. | 03-04-2010 |
20100069978 | DUAL SENSING FOR BRADY-TACHY PACEMAKER/ICD - A system detects events related to cardiac activity. The system comprises a primary cardiac signal sensing circuit, at least one secondary cardiac signal sensing circuit having a higher sensitivity than the primary sensing circuit, and a controller circuit coupled to the primary and secondary cardiac signal sensing circuits. The controller circuit determines a rate of depolarization using the primary sensing circuit and detects tachyarrhythmia using the rate. The controller circuit also detects tachyarrhythmia using the secondary sensing circuit and also deems the tachyarrhythmia valid if the controller circuit detects the tachyarrhythmia using both the primary and secondary sensing circuit. | 03-18-2010 |
20100121209 | Arrhythmia Discrimination Based on Determination of Rate Dependency - Cardiac systems and methods provide for discriminating between supraventricular tachyarrhythmia and ventricular tachyarrhythmia based on a determination that the patient's supraventricular rhythm exhibits rate dependency. One approach involves determining if a patient's supraventricular rhythm exhibits rate dependent morphology. If the patient's supraventricular rhythm is determined to exhibit rate dependent morphology, an implantable device classifies a detected tachyarrhythmia episode based on one or more templates selected from a plurality of rate-indexed templates stored in the device. Determining if the supraventricular rhythm exhibits rate dependent morphology may also include determining one or more rates at which the rate dependent morphology occurs. | 05-13-2010 |
20100145400 | Arrhythmia Classification and Therapy Selection - Different types of cardiac arrhythmia are classified based on the morphology of the arrhythmic beats. Cardiac beats associated with an arrhythmic episode are compared to a plurality of representative beat morphologies, each representative beat morphology characterizing a type of arrhythmia of the heart. An arrhythmic episode may be classified as a particular type of arrhythmia if the morphology of the arrhythmic cardiac beats matches a representative beat morphology characterizing the particular type of arrhythmia. An appropriate therapy for the particular type of arrhythmia may be selected based on the arrhythmia classification. A particular type of arrhythmia may be associated with one or more therapies used to treat the arrhythmia. The therapy used to treat the arrhythmia may comprise a therapy identified as a previously successful therapy. | 06-10-2010 |
20100152803 | METHOD AND APPARATUS FOR DETECTING NON-SUSTAINING VENTRICULAR TACHYARRHYTHMIA - An implantable medical device controls an anti-tachyarrhythmia therapy by detecting a tachyarrhythmia episode from a cardiac signal and analyzing the detected tachyarrhythmia episode in a tachyarrhythmia detection and analysis process to determine whether the anti-tachyarrhythmia therapy needs to be delivered. The tachyarrhythmia detection and classification process includes detection of inhibitory events each indicating that the tachyarrhythmia episode is of a type not to be treated by the anti-tachyarrhythmia therapy or that the tachyarrhythmia episode is not sustaining. The detection of each of the inhibitory events causes the tachyarrhythmia detection and classification process to be restarted or extended, or the delivery of the anti-tachyarrhythmia therapy to be withheld. | 06-17-2010 |
20100168597 | ZONELESS TACHYARRHYTHMIA DETECTION WITH REAL-TIME RHYTHM MONITORING - A method of using an implantable medical device (IMD) comprising monitoring a ventricular contraction rate of a subject, monitoring an atrial contraction rate of the subject, declaring tachyarrhythmia if the ventricular contraction rate exceeds the atrial contraction rate, and declaring a slow tachyarrhythmia when the ventricular rate is less than a specified tachyarrhythmia detection rate. | 07-01-2010 |
20100168813 | Capture Verification Using An Evoked Response Reference - 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. | 07-01-2010 |
20100168814 | Method and System for Detecting Capture with Cancellation of Pacing Artifact - 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. | 07-01-2010 |
20100262030 | RHYTHM DISCRIMINATION OF SUDDEN ONSET AND ONE-TO-ONE TACHYARRHYTHMIA - This document discusses, among other things, systems and methods to discriminate between a ventricular tachyarrhythmia (VT) and a supraventricular tachyarrhythmia (SVT), such as upon detecting sudden onset and one-to-one tachycardia. In certain examples, a detected tachyarrhythmia is analyzed to determine whether it is sudden onset and 1:1. If so, a first fast beat is identified. One or more ventricular intervals in close proximity to the first fast beat are analyzed to determine an initial classification of either VT or SVT. The initial classification is used to adjust a morphological feature correlation coefficient (FCC) threshold. A morphology analysis is performed with the adjusted FCC threshold value to yield a secondary classification. | 10-14-2010 |
20100274146 | DYNAMIC SELECTION OF ALGORITHMS FOR ARRHYTHMIA DETECTION - An apparatus comprises a first implantable sensor produces a first electrical sensor signal representative of cardiac depolarization events of a heart of a subject, a second implantable sensor that produces a second electrical sensor signal representative of hemodynamic function of the heart, a signal analyzer circuit, and an arrhythmia discrimination circuit. The signal analyzer circuit detects an arrhythmic event from the first sensor signal and calculates hemodynamic stability in response to the arrhythmic event detection using the second sensor signal. The arrhythmia discrimination circuit selects, according to a calculated hemodynamic stability produced by the signal analyzer circuit, an arrhythmia discrimination algorithm from among a plurality of candidate arrhythmia discrimination algorithms that are implementable by the arrhythmia discrimination circuit, classifies the detected arrhythmia using the selected arrhythmia discrimination algorithm, and provides the arrhythmia classification to a user or process. | 10-28-2010 |
20100280400 | RATE ABERRANT BEAT SELECTION AND TEMPLATE FORMATION - A cardiac rhythm management system can be used to detect episode beats associated with cardiac events in a subject's body. These events may be monitored and depolarization morphology information can be derived for candidate arrhythmic beats in an arrhythmia episode. An arrhythmic beat morphology template may be formed from selecting at least one of the candidate arrhythmic beats based upon user's labeling according to specific morphologies of one or more candidate episodes. Methods of use are also presented. | 11-04-2010 |
20100298902 | TACHYARRHYTHMIA SUDDEN ONSET DETECTION WITH HYSTERESIS - This document discusses, among other things, detection of a sudden onset of a tachyarrhythmia. A sudden onset of tachyarrhythmia is determined by monitoring changes in intrinsic ventricular rate, such as by using one or more sensing channels in the ICD. A lowest tachyarrhythmia rate threshold is accompanied by a slightly lower “hysteresis tachyarrhythmia rate threshold.” If a sudden onset of tachyarrhythmia is declared, the sudden onset status is not reset by the ventricular rate falling below the lowest tachyarrhythmia rate threshold, but is instead reset by the ventricular rate falling below the slightly lower hysteresis tachyarrhythmia rate threshold. | 11-25-2010 |
20100324438 | Detection of Disordered Breathing - Devices and methods for detecting disordered breathing involve determining that the patient is asleep and sensing one or more signals associated with disordered breathing indicative of sleep-disordered breathing while the patient is asleep. Sleep-disordered breathing is detected using the sensed signals associated with disordered breathing. The sensed signals associated with disordered breathing may also be used to acquire a respiration pattern of one or more respiration cycles. Characteristics of the respiration pattern are determined. The respiration pattern is classified as a disordered breathing episode based on the characteristics of the respiration pattern. One or more processes involved in the detection of disordered breathing are performed using an implantable device. | 12-23-2010 |
20100324613 | METHOD AND APPARATUS FOR RATE ACCURACY ENHANCEMENT IN VENTRICULAR TACHYCARDIA DETECTION - An implantable cardioverter/defibrillator (ICD) executes a rate accuracy enhancement algorithm to select measured atrial and ventricular intervals for classifying a detected tachycardia based on average atrial and ventricular rates calculated from the selected atrial and ventricular intervals. The detected tachycardia is classified as ventricular tachycardia (VT) if the average ventricular rate is substantially higher than the average atrial rate. | 12-23-2010 |
20110021934 | BLENDING CARDIAC RHYTHM DETECTION PROCESSES - Systems and methods are described for classifying a cardiac rhythm. A cardiac rhythm is classified using a classification process that includes a plurality of cardiac rhythm discriminators. Each rhythm discriminator provides an independent classification of the cardiac rhythm. The classification process is modified if the modification is likely to produce enhanced classification results. The rhythm is reclassified using the modified classification process. | 01-27-2011 |
20110130672 | SELF-ADJUSTING ECG MORPHOLOGICAL FEATURE CORRELATION THRESHOLD - An apparatus comprises first and second sensing circuits, a template generator circuit, and a correlation circuit. The correlation circuit is configured to identify a first fiducial position in a third cardiac signal sensed using the first sensing circuit during a detected rhythm with elevated ventricular rate, align the template correlation features and the correlation features of a fourth cardiac signal using the first fiducial position, calculate a correlation using the correlation features of the template and the correlation features of the fourth cardiac signal, and iteratively searching for a replacement to the first fiducial position in the third cardiac signal according to the calculated correlation. | 06-02-2011 |
20110160551 | METHOD AND APPARATUS FOR MORPHOLOGY-BASED ARRHYTHMIA CLASSIFICATION USING CARDIAC AND OTHER PHYSIOLOGICAL SIGNALS - A tachyarrhythmia detection and classification system classifies tachyarrhythmias based on an analysis of morphological features of a cardiac signal enhanced by using one or more physiological parameters indicative of hemodynamic stability and/or activity level. The tachyarrhythmia detection and classification system computes a measure of similarity between an arrhythmic waveform of the cardiac signal, a template waveform for that cardiac signal, such as a correlation coefficient representative of the correlation between morphological features of the arrhythmic waveform and morphological features of the template waveform. A detected tachyarrhythmia episode is classified by comparing the measure of similarity to a threshold that is dynamically adjusted using the one or more physiological parameters. | 06-30-2011 |
20110288603 | POST-SHOCK RECOVERY MONITORING FOR TACHYARRHYTHMIA DISCRIMINATION - A cardiac rhythm management device is configured to discriminate between ventricular and supraventricular tachycardias (referred to as SVT/VT discrimination) by utilizing a morphology criterion in which the morphology of electrogram waveforms during ventricular beats are analyzed to determine if the beats are normally conducted. After the delivery of a cardioversion/defibrillation shock, however, the intraventricular conduction system is left in a modified state which alters the subsequently generated electrogram signal. Use of the morphology criterion for to SVT/VT discrimination is discontinued after delivery of such a shock and resumed after a predetermined minimum number of normally conducted ventricular beats has been detected. | 11-24-2011 |
20120035492 | Atrial Tachyarrhythmia Detection using Selected Atrial Intervals - Methods and systems are directed to detecting atrial tachyarrhythmia. A plurality of A-A intervals is detected. The detected A-A intervals are selected and used to detect atrial tachyarrhythmia. Selecting A-A intervals may be based on determining that A-A intervals are qualified. Qualified A-A intervals may be determined if a duration of the particular A-A interval falls outside a predetermined duration range, for example. Qualified A-A intervals may also be determined based on events occurring between consecutively sensed atrial events of the particular A-A interval, and whether the duration of the particular A-A interval falls within the predetermined duration range, for example. | 02-09-2012 |
20120065696 | Method and System for Characterizing Supraventricular Rhythm during Cardiac Pacing - A method and system for generating a characterization of one beat of a patient's supraventricular rhythm (SVR) involves performing such characterization while the heart is being paced. During SVR characterization, various pacing parameters are modified and the patient's supraventricular rhythm is characterized while the pacing parameters are modified. The SVR characterization process is effective in single and multiple chamber pacing modes. | 03-15-2012 |
20120179057 | BLENDING CARDIAC RHYTHM DETECTION PROCESSES - Systems and methods are described for classifying a cardiac rhythm. A cardiac rhythm is classified using a classification process that includes a plurality of cardiac rhythm discriminators. Each rhythm discriminator provides an independent classification of the cardiac rhythm. The classification process is modified if the modification is likely to produce enhanced classification results. The rhythm is reclassified using the modified classification process. | 07-12-2012 |
20120215273 | METHOD AND APPARATUS FOR CONCURRENT ATRIO-VENTRICULAR ANTI-TACHYCARDIA PACING - An implantable medical device delivers anti-tachyarrhythmia therapies including anti-tachycardia pacing (ATP). If a detected tachyarrhythmia is classified as a type suitable for treatment using ATP, the implantable medical device selects one of an atrial ATP (A-ATP) mode, a ventricular ATP (V-ATP) mode, and a concurrent atrio-ventricular ATP (concurrent AV-ATP) mode according to the characteristics of the detected tachyarrhythmia. The concurrent ATP mode is an ATP mode during which the atrial pacing pulses and the ventricular pacing pulses are delivered concurrently. In one embodiment, the concurrent AV-ATP mode includes a synchronized atrio-ventricular ATP (synchronized AV-ATP) mode during which atrial and ventricular pacing pulses are delivered synchronously and an independent atrio-ventricular ATP (independent AV-ATP) mode during which atrial and ventricular pacing pulses are delivered concurrently but timed independently. | 08-23-2012 |
20130053705 | CARDIAC CYCLE SYNCHRONIZED SAMPLING OF IMPEDANCE SIGNAL - A system comprising implantable device, the implantable medical device including an intrinsic cardiac signal sensor, an impedance measurement circuit configured to apply a specified current to a transthoracic region of a subject and to sample a transthoracic voltage resulting from the specified current, and a processor coupled to the intrinsic cardiac signal sensor and the impedance measurement circuit. The processor is configured to initiate sampling of a transthoracic voltage signal in a specified time relation to a fiducial marker in a sensed intrinsic cardiac signal, wherein the sampling attenuates or removes variation with cardiac stroke volume from the transthoracic voltage signal, and determine lung respiration using the sampled transthoracic voltage signal. | 02-28-2013 |
20130253340 | CARDIAC CYCLE SYNCHRONIZED SAMPLING OF IMPEDANCE SIGNAL - A system comprising implantable device, the implantable medical device including an intrinsic cardiac signal sensor, an impedance measurement circuit configured to apply a specified current to a transthoracic region of a subject and to sample a transthoracic voltage resulting from the specified current, and a processor coupled to the intrinsic cardiac signal sensor and the impedance measurement circuit. The processor is configured to initiate sampling of a transthoracic voltage signal in a specified time relation to a fiducial marker in a sensed intrinsic cardiac signal, wherein the sampling attenuates or removes variation with cardiac stroke volume from the transthoracic voltage signal, and determine lung respiration using the sampled transthoracic voltage signal. | 09-26-2013 |
20130338725 | CARDIAC RESPONSE CLASSIFICATION USING MULTISITE SENSING AND PACING - Methods and devices for classifying a cardiac pacing response involve using a first electrode combination for pacing and a second electrode combination for sensing a cardiac signal following pacing. The cardiac response to pacing may be classified using the sensed cardiac signal. One process involves using the sensed cardiac signal to detect the cardiac response as a fusion/pseudofusion beat. Another process involves using the sensed cardiac signal to classify the cardiac response to pacing as one of at least three cardiac response types. | 12-19-2013 |
20140163398 | CARDIAC CYCLE SYNCHRONIZED SAMPLING OF IMPEDANCE SIGNAL - A system comprising implantable device, the implantable medical device including an intrinsic cardiac signal sensor, an impedance measurement circuit configured to apply a specified current to a transthoracic region of a subject and to sample a transthoracic voltage resulting from the specified current, and a processor coupled to the intrinsic cardiac signal sensor and the impedance measurement circuit. The processor is configured to initiate sampling of a transthoracic voltage signal in a specified time relation to a fiducial marker in a sensed intrinsic cardiac signal, wherein the sampling attenuates or removes variation with cardiac stroke volume from the transthoracic voltage signal, and determine lung respiration using the sampled transthoracic voltage signal. | 06-12-2014 |
20150051662 | CARDIAC RESPONSE CLASSIFICATION USING MULTISITE SENSING AND PACING - Methods and devices for classifying a cardiac pacing response involve using a first electrode combination for pacing and a second electrode combination for sensing a cardiac signal following pacing. The cardiac response to pacing may be classified using the sensed cardiac signal. One process involves using the sensed cardiac signal to detect the cardiac response as a fusion/pseudofusion beat. Another process involves using the sensed cardiac signal to classify the cardiac response to pacing as one of at least three cardiac response types. | 02-19-2015 |