Patent application number | Description | Published |
20090177104 | System and Method for Distinguishing Among Cardiac Ischemia, Hypoglycemia and Hyperglycemia Using an Implantable Medical Device - Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia. | 07-09-2009 |
20090177105 | System and Method for Distinguishing Among Cardiac Ischemia, Hypoglycemia and Hyperglycemia Using an Implantable Medical Device - Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia. | 07-09-2009 |
20090270939 | DEVICE AND METHOD FOR DETECTING ATRIAL FIBRILLATION - Detection of atrial fibrillation involves detecting a plurality of ventricular events and obtaining a series of probabilities of AF, each corresponding to a probability of AF for a different beat window having a plurality of ventricular events. AF onset is detected when one or each of a plurality of consecutive AF probabilities satisfies an AF trigger threshold. AF termination is detected when one or each of a plurality of consecutive AF probabilities does not satisfy the AF trigger threshold. Upon detection of AF onset, ventricular events are processed to detect for a sudden onset of irregularity of the ventricular events. AF onset is confirmed when sudden onset is detected and overturned when sudden onset is not detected. | 10-29-2009 |
20090318987 | ISCHEMIA DETECTION FOR ANTI-ARRHYTHMIA THERAPY - An exemplary method includes detecting arrhythmia, detecting myocardial ischemia, determining whether the myocardial ischemia comprises local ischemia or global ischemia and, in response to the determining, calling for delivery of either a local ischemic anti-arrhythmia therapy or a global ischemic anti-arrhythmia therapy. Various other exemplary methods, devices, systems, etc., are also disclosed. | 12-24-2009 |
20100081952 | DETECTING ISCHEMIA USING AN IMPLANTABLE CARDIAC DEVICE BASED ON MORPHOLOGY OF CARDIAC PRESSURE SIGNAL - Methods and systems are presented for using an ICD to detect myocardial ischemia. One such method includes sensing via an implantable cardiac-rhythm-management device (ICRMD) a signal indicative of cardiac pressure; determining via a processor associated with the ICRMD, a derivative signal that is a first derivative of the sensed signal; measuring via the processor, a maximum positive value of the derivative signal; measuring via the processor, a maximum negative value of the derivative signal; and indicating via the processor, an ischemia based on a comparison of a ratio of the maximum positive value to the maximum negative value with a predetermined value. | 04-01-2010 |
20100121394 | System and Method for Setting Atrioventricular Pacing Delays Based on Far-Field Atrial Signals - An intrinsic inter-atrial conduction delay is determined by a pacemaker or implantable cardioverter-defibrillator based, at least in part, on far-field atrial events sensed using ventricular pacing/sensing leads. An atrioventricular pacing delay is then set based on the inter-atrial conduction delay. By detecting atrial events using ventricular leads, rather than using atrial leads, a more useful measurement of the intrinsic inter-atrial conduction delay can be obtained. In this regard, since atrial electrodes detect atrial activity locally around the electrodes, a near-field atrial event sensed using an atrial electrode might not properly represent the actual timing of the atrial event across both the right and left atria. Far-field atrial events sensed using ventricular leads thus allow for a more useful measurement of inter-atrial conduction delays for use in setting atrioventricular pacing delays. The delivery of individual V-pulses to the heart of the patient may be timed relative to the ends of individual far-field atrial events. | 05-13-2010 |
20100121395 | System and Method for Setting Atrioventricular Pacing Delays Based on Far-Field Atrial Signals - An intrinsic inter-atrial conduction delay is determined by a pacemaker or implantable cardioverter-defibrillator based, at least in part, on far-field atrial events sensed using ventricular pacing/sensing leads. An atrioventricular pacing delay is then set based on the inter-atrial conduction delay. By detecting atrial events using ventricular leads, rather than using atrial leads, a more useful measurement of the intrinsic inter-atrial conduction delay can be obtained. In this regard, since atrial electrodes detect atrial activity locally around the electrodes, a near-field atrial event sensed using an atrial electrode might not properly represent the actual timing of the atrial event across both the right and left atria. Far-field atrial events sensed using ventricular leads thus allow for a more useful measurement of inter-atrial conduction delays for use in setting atrioventricular pacing delays. The delivery of individual V-pulses to the heart of the patient may be timed relative to the ends of individual far-field atrial events. | 05-13-2010 |
20100121396 | ENHANCED HEMODYNAMICS THROUGH ENERGY-EFFICIENT ANODAL PACING - An implantable device may employ anodal-based cardiac stimulation to improve hemodynamics. Anodal pacing may be provided on a conditional basis (e.g., upon detection of a defined condition). An implantable device may provide anodal pacing or cathodal pacing according to a defined ratio. An implantable device may use automatic capture detection to determine a pacing energy level that provides effective anodal pacing while attempting to minimize the power consumption associated with the anodal pacing. | 05-13-2010 |
20110004111 | ISCHEMIA DETECTION USING INTRA-CARDIAC SIGNALS - An implanted cardiac rhythm management device is disclosed that is operative to detect myocardial ischemia. This is done by evaluating electrogram features to detect an electrocardiographic change; specifically, changes in electrogram segment during the early part of an ST segment. The early part of the ST segment is chosen to avoid the T-wave. | 01-06-2011 |
20110015690 | Neurostimulation and Neurosensing Techniques to Optimize Atrial Anti-Tachycardia Pacing for Prevention of Atrial Tachyarrhythmias - Implantable systems and method for use therewith are provided that take advantage of various neuromodulation and neurosensing techniques for either preventing atrial fibrillation (AF) or terminating AF. Specific embodiments are for use with an implantable device that includes one or more atrial electrode for sensing atrial fibrillation (AF) and/or delivering AATP and one or more electrode for monitoring and/or stimulating atrial vagal fat pads. | 01-20-2011 |
20110060230 | DETERMINATION OF DIASTOLIC HEART FAILURE - An exemplary method includes detecting a change in state of a cardiac valve, detecting elongation of the left ventricle substantially along its major axis, determining a time difference between the change in state of the cardiac valve and the elongation of the left ventricle and, based at least in part on the time difference, deciding whether a diastolic abnormality exists. Other exemplary methods, devices, systems, etc., are also disclosed. | 03-10-2011 |
20110125206 | SINGLE CHAMBER IMPLANTABLE MEDICAL DEVICE FOR CONFIRMING ARRHYTHMIA THROUGH RETROSPECTIVE CARDIAC SIGNALS - An implantable medical device is provided that comprises a housing, sensors configured to be located to proximate a heart, and a sensing module to sense cardiac signals originating from the heart over a channel defined by the sensors. The cardiac signals include intrinsic R-wave events and associated intrinsic confirmation events when the heart exhibits normal sinus rhythm. The device further includes memory to store the cardiac signals sensed over a channel, and a detection module. The detection module identifies an R-wave event within the cardiac signals. The detection module captures, in the memory, a segment of the cardiac signals that precedes the R-wave event as a retrospective segment. The detection module determines whether the retrospective segment includes an intrinsic confirmation event that is associated with and occurs before the R-wave event. The detection module declares an arrhythmia based at least in part on the determination of whether the retrospective segment includes the intrinsic confirmation event is absent from the retrospective segment. | 05-26-2011 |
20110137364 | MULTI-SITE PACING FOR ATRIAL TACHYARRHYTHMIAS - Tachyarrhythmia is treated by applying anti-tachycardia pacing through at least one multi-site electrode set located on, in or around the heart. The electrode set is arranged and located such that an electrical activation pattern having a wave-front between substantially flat and concave is generated through a reentrant circuit associated with the tachyarrhythmia. The electrode set may be one of a plurality of predefined, multi-site electrode sets located on, in or around the atria. Alternatively, the electrode set may be formed using at least two selectable electrodes located on, in or around the atria | 06-09-2011 |
20120065527 | Methods and Systems for Monitoring Aterial Stiffness - Implanted systems and methods for monitoring a patient's arterial stiffness are provided. An implanted sensor is used to produce a signal indicative of changes in arterial blood volume for a plurality of beats of the patient's heart. A pulse duration metric is determined for each of a plurality of pulses of the signal, wherein each pulse of the signal corresponds to a beat of the patient's heart. Arterial stiffness is monitored based on the determined pulse duration metric for the plurality of pulses of the signal. This can include monitoring arterial stiffness based on a dispersion of the pulse duration metric and/or an average of the pulse duration metric. | 03-15-2012 |
20120065528 | PRE-EJECTION INTERVAL (PEI) MONITORING DEVICES, SYSTEMS AND METHODS - Provided herein are implantable systems, and methods for use therewith, for monitoring a patient's pre-ejection interval (PEI). A signal indicative of cardiac electrical activity and a signal indicative of changes in arterial blood volume are obtained. One or more predetermined features of the signal indicative of cardiac electrical activity and the signal indicative of changes in arterial blood volume are detected. The patient's PEI is determined by determining an interval between the predetermined feature of the signal indicative of cardiac electrical activity and the predetermined feature of the signal indicative of changes in arterial blood volume. | 03-15-2012 |
20120158079 | SYSTEMS AND METHODS FOR ASSESSING THE SPHERICITY AND DIMENSIONAL EXTENT OF HEART CHAMBERS FOR USE WITH AN IMPLANTABLE MEDICAL DEVICE - Techniques are provided for use with an implantable medical device for assessing left ventricular (LV) sphericity and atrial dimensional extent based on impedance measurements for the purposes of detecting and tracking heart failure and related conditions such as volume overload or mitral regurgitation. In some examples described herein, various short-axis and long-axis impedance vectors are exploited that pass through portions of the LV for the purposes of assessing LV sphericity. In other examples, impedance measurements taken along a vector between a right atrial (RA) ring electrode and an LV electrode implanted near the atrioventricular (AV) groove are exploited to assess LA extent, biatrial extent or mitral annular diameter. The assessment techniques can be employed alone or in conjunction with other heart failure detection techniques, such as those based on left atrial pressure (LAP.) | 06-21-2012 |
20120165884 | FLUID ACCUMULATION MONITORING DEVICES, SYSTEMS AND METHODS - Provided herein are implantable systems, and methods for use therewith, for monitoring a patient's fluid accumulation level. A thoracic impedance signal for the patient is obtained. Based on the thoracic impedance signal, a duration metric indicative of a duration of drop of the thoracic impedance signal, a magnitude metric indicative of a magnitude of drop of the thoracic impedance signal, and a rate metric indicative of a rate of drop of the thoracic impedance signal is determined. The patient's fluid accumulation level is monitored based on the duration metric, the magnitude metric and the rate metric. | 06-28-2012 |
20120190957 | SYSTEM AND METHOD FOR MONITORING CARDIAC DISEASE - A method of monitoring progression of cardiac disease includes applying stimulus pulses to the heart and sensing electrophysiological responses of the heart at a plurality of different monitoring locations of the heart. The method also includes comparing a previously and subsequently sensed electrophysiological responses that are sensed near a first location of the monitoring locations and comparing previously and subsequently sensed electrophysiological responses that are sensed near a second location of the monitoring locations. The method further includes identifying a change in progression of cardiac disease of the heart based on a difference between the previously and subsequently sensed electrophysiological responses at the first location and based on a difference between the previously and subsequently sensed electrophysiological responses at the second location. | 07-26-2012 |
20120197149 | SYSTEM AND METHOD FOR DISTINGUISHING AMONG CARDIAC ISCHEMIA, HYPOGLYCEMIA AND HYPERGLYCEMIA USING AN IMPLANTABLE MEDICAL DEVICE - Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia. | 08-02-2012 |
20120215117 | SYSTEMS AND METHODS FOR ESTIMATING CENTRAL ARTERIAL BLOOD PRESSURE OF A PATIENT - In specific embodiments, a method for estimating a patient's central arterial blood pressure (CBP) for use with an implantable system, comprises (a) using an implanted sensor at a first site to obtain a first signal indicative of changes in arterial blood volume at the first site, the first site being along one or more peripheral arterial structures of the patient, (b) using an implanted sensor at a second site to obtain a second signal indicative of changes in arterial blood volume at the second site, the second site being a distance from the first site downstream along an arterial path of the peripheral arterial structure of the patient, and (c) using implanted electrodes to obtain a signal indicative of electrical activity of the patient's heart. The method further comprises (d) determining a time t | 08-23-2012 |
20120215275 | IMPLANTABLE SYSTEMS AND METHODS FOR USE THEREWITH FOR MONITORING AND MODIFYING ARTERIAL BLOOD PRESSURE WITHOUT REQUIRING AN INTRAVASCULAR PRESSURE TRANSDUCER - Embodiments of the present invention are directed to implantable systems, and methods for use therewith, that monitor and modify a patient's arterial blood pressure without requiring an intravascular pressure transducer. In accordance with an embodiment, for each of a plurality of periods of time, there is a determination one or more metrics indicative of pulse arrival time (PAT), each of which are indicative of how long it takes for the left ventricle to generate a pressure pulsation that travels from the patient's aorta to a location remote from the patient's aorta. Based on the one or more metrics indicative of PAT, the patient's arterial blood pressure is estimated. Changes in the arterial blood pressure are monitored over time. Additionally, the patient's arterial blood pressure can be modified by initiating and/or adjusting pacing and/or other therapy based on the estimates of the patient's arterial blood pressure and/or monitored changes therein. | 08-23-2012 |
20120221066 | Systems and Methods for Activating and Controlling Impedance-Based Detection Systems of Implantable Medical Devices - Techniques are provided for use with implantable medical devices for addressing encapsulation effects, particularly in the detection of cardiac decompensation events such as heart failure (HF) or cardiogenic pulmonary edema (PE.) In one example, during an acute interval following device implant, cardiac decompensation is detected using heart rate variability (HRV), ventricular evoked response (ER) or various other non-impedance-based parameters that are insensitive to component encapsulation effects. During the subsequent chronic interval, decompensation is detected using intracardiac or transthoracic impedance signals. In another example, the degree of maturation of encapsulation of implanted components is assessed using impedance frequency-response measurements or based on the frequency bandwidth of heart sounds or other physiological signals. In this manner, impedance-based HF/PE detection systems can be activated as soon as component encapsulation has matured, without necessarily waiting until completion of a preset post-implant maturation interval, often set to forty-five days or more. | 08-30-2012 |
20120221069 | Systems and Methods for Activating and Controlling Impedance-Based Detection Systems of Implantable Medical Devices - Techniques are provided for use with implantable medical devices for addressing encapsulation effects, particularly in the detection of cardiac decompensation events such as heart failure (HF) or cardiogenic pulmonary edema (PE.) In one example, during an acute interval following device implant, cardiac decompensation is detected using heart rate variability (HRV), ventricular evoked response (ER) or various other non-impedance-based parameters that are insensitive to component encapsulation effects. During the subsequent chronic interval, decompensation is detected using intracardiac or transthoracic impedance signals. In another example, the degree of maturation of encapsulation of implanted components is assessed using impedance frequency-response measurements or based on the frequency bandwidth of heart sounds or other physiological signals. In this manner, impedance-based HF/PE detection systems can be activated as soon as component encapsulation has matured, without necessarily waiting until completion of a preset post-implant maturation interval, often set to forty-five days or more. | 08-30-2012 |
20120239104 | METHOD AND SYSTEM TO CORRECT CONTRACTILITY BASED ON NON-HEART FAILURE FACTORS - A method is provided for trending heart failure based on heart contractility information comprises measuring cardiogenic impedance (CI) measurements along at least a first vector through a heart over a period of time. The method determines contractility estimates from the CI measurements, the contractility estimates relating to contractility of the heart. The method further obtains physiologic and/or surrogate signals representing estimates for or direct measurements of at least one of cardiac volume and pressure of the heart when the CI measurements were obtained. The method identifies correction factors based on the physiologic and/or surrogate signals and applies the correction factors to the contractility estimates to produce contractility trend values over the period of time. A system is provided for trending heart failure based on heart contractility information which comprises inputs to receive cardiogenic impedance (CI) measurements taken along at least a first vector through a heart over a period of time. The system includes a contractility module to determine contractility estimates from the CI measurements, the contractility estimates relating to contractility of the heart and a collection module to receive physiologic and/or surrogate signals representing estimates for or direct measurements of at least one of cardiac volume and pressure of the heart when the CI measurements were obtained. A factor module is also provided to identify correction factors based on the physiologic and/or surrogate signals and a correction module to apply the correction factors to the contractility estimates to produce contractility trend values over the period of time. | 09-20-2012 |
20130041274 | SYSTEMS AND METHODS FOR USE BY IMPLANTABLE MEDICAL DEVICES FOR DETECTING AND DISCRIMINATING STROKE AND CARDIAC ISCHEMIA USING ELECTROCARDIAC SIGNALS - Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart. In still other examples, the device detects cardiac ischemia occurring during stroke. | 02-14-2013 |
20130158619 | MULTI-VENTRICULAR SITE TIMING OPTIMIZATION USING CARDIOGENIC IMPEDANCE - A method of calculating a timing delay for an implantable medical device based on cardiogenic impedance estimates cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart. The method also determines the timing delay based on the estimated cardiogenic impedance. | 06-20-2013 |
20130204312 | SYSTEMS AND METHODS FOR CONTROLLING PACING INDUCED DYSSYNCHRONY TO REDUCE ISCHEMIC INJURY USING AN IMPLANTABLE MEDICAL DEVICE - Techniques are provided for use by an implantable medical device for optimizing the amount of ventricular dyssynchrony induced within a patient during protective pacing. In one example, the device analyzes intracardiac electrogram signals to detect an ischemic event within the heart. The device then delivers pacing stimulus in accordance with adjustable pacing parameters to induce ventricular dyssynchrony within the heart and adjusts the pacing parameters within a range of permissible values to achieve a preferred degree of ventricular dyssynchrony within the patient, so long as there is no significant reduction in left ventricular pumping functionality. Preferably, the pacing parameters are adjusted to maximize or otherwise optimize the degree of dyssynchrony induced within the patient. If a significant reduction in LV pumping functionality is detected, the dyssynchrony-inducing pacing is preferably suspended to avoid any deterioration in the condition of the heart. Techniques for detecting early onset of ischemia are also disclosed. | 08-08-2013 |