Patent application number | Description | Published |
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 |
20090318822 | Methods and systems for analyzing t-wave alternants - Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias. | 12-24-2009 |
20100057155 | IMPLANTABLE SYSTEMS AND METHOD FOR USE THEREWITH FOR TRACKING CHANGES IN HEMODYNAMICS AND CARDIAC DISEASE - Embodiments of the present invention relate to monitoring a patient's atrial stretch, heart failure (HF) condition, and/or risk of atrial fibrillation (AF), as well as methods for estimating a change in at least one of a patient's left atrial pressure (LAP), pulmonary capillary wedge pressure (PCWP), and right pulmonary artery pressure (RPAP). Embodiments of the present invention also relate to selecting a pacing energy level. Such embodiments involve determining atrial evoked response metrics when a patient's atrium is paced, and monitoring changes in such metrics. | 03-04-2010 |
20100057158 | Neurostimulation Based On Glycemic Condition - A glycemic condition is indicated based on variance of a feature derived from cardiac electrogram data. Neurostimulation is then used to counteract a cardiac-related autonomic response to the glycemic condition. For example, stimulation of parasympathetic innervation may be used to counteract an autonomic sympathetic response that is associated with hypoglycemia or hyperglycemia. In addition, stimulation of sympathetic innervation may be used to counteract an autonomic parasympathetic response that is associated with hypoglycemia or hyperglycemia. | 03-04-2010 |
20100160804 | MONITORING VARIATION PATTERNS IN PHYSIOLOGICAL PARAMETERS ASSOCIATED WITH MYOCARDIAL INSTABILITY - A method of analyzing myocardial instability includes obtaining a physiological parameter representative of myocardial behavior over a set of cardiac cycles and determining reversal points in the physiological parameter over the set of cardiac cycles. The method also includes identifying myocardial instability based on the reversal points in the physiological parameter. A reversal point may correspond to a value of the physiological parameter, during a current cardiac cycle, that exceeds or is less than the values of the physiological parameter during prior and subsequent cardiac cycles. Optionally, the method includes calculating differences between values of the physiological parameter for consecutive cardiac cycles and detecting the reversal points when a current difference exceeds or is less than differences for prior and subsequent cardiac cycles. | 06-24-2010 |
20110125049 | Methods and Systems that Use Implanted Posture Sensor to Monitor Pulmonary Edema - In specific embodiments, a method to monitor pulmonary edema of a patient, comprises (a) detecting, using an implanted posture sensor, when a posture of the patient changes from a first predetermined posture to a second predetermined posture, (b) determining an amount of time it takes an impedance signal to achieve a steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture, where the impedance signal is obtained using implanted electrodes and is indicative of left atrial pressure and/or intra-thoracic fluid volume of the patient, and (c) monitoring the pulmonary edema of the patient based on the determined amount of time it takes the impedance signal to achieve the steady state after the posture of the patient changes from the first predetermined posture to the second pre-determined posture. | 05-26-2011 |
20110125207 | METHODS AND SYSTEMS THAT USE IMPLANTED POSTURE SENSOR TO MONITOR LEFT ATRIAL PRESSURE AND/OR INTER-THORACIC FLUID VOLUME - In specific embodiments, a method to monitor left atrial pressure and/or intra-thoracic fluid volume of a patient, comprises (a) monitoring posture of the patient using a posture sensor implanted within the patient, and (b) using portions of an impedance signal, obtained using implanted electrodes, to monitor the left atrial pressure and/or intra-thoracic fluid volume of the patient. Each portion of the impedance signal used to monitor the left atrial pressure and/or intra-thoracic fluid volume of the patient corresponds to a period after which the patient has maintained a predetermined posture for at least a predetermined period of time, and during which the patient has remained in the predetermined posture. | 05-26-2011 |
20120035493 | NEAR FIELD-BASED SYSTEMS AND METHODS FOR ASSESSING IMPEDANCE AND ADMITTANCE FOR USE WITH AN IMPLANTABLE MEDICAL DEVICE - A new model is provided for understanding and exploiting impedance or admittance values measured by implantable medical devices, such as pacemakers or cardiac resynchronization devices (CRTs.) The device measures impedance along vectors extending through tissues of the patient between various pairs of electrodes. The device then converts the vector-based impedance measurements into near-field individual electrode-based impedance values. This is accomplished, in at least some examples, by converting the vector-based impedance measurements into a set of linear equations to be solved while ignoring far-field contributions to the impedance measurements. The device solves the linear equations to determine the near-field impedance values for the individual electrodes, which are representative of the impedance of tissues in the vicinity of the electrodes. The device then performs or controls various device functions based on the near-field values, such as analyzing selected near-field values to detect heart failure or pulmonary edema. | 02-09-2012 |
20120035495 | SYSTEMS AND METHODS FOR EXPLOITING NEAR-FIELD IMPEDANCE AND ADMITTANCE FOR USE WITH IMPLANTABLE MEDICAL DEVICES - Various techniques are provided for use with an implantable medical device for exploiting near-field impedance/admittance. Examples include techniques for assessing heart chamber disequilibrium, detecting chamber volumes and pressures, calibrating near-field-based left atrial pressure (LAP) estimation procedures and for assessing the recovery from injury at the electrode-tissue interface. In one particular example, the implantable device assesses the degree of concordance between the left ventricle (LV) and the right ventricle (RV) by quantifying a degree of scatter between LV and RV near-field admittance values. An increase in RV admittance is indicative of RV failure, an increase in LV admittance is indicative of LV failure, and an increase in both LV and RV admittance is indicative of biventricular failure. | 02-09-2012 |
20120035681 | SYSTEMS AND METHODS FOR ESTIMATING LEFT ATRIAL PRESSURE (LAP) IN PATIENTS WITH ACUTE MITRAL VALVE REGURGITATION FOR USE BY AN IMPLANTABLE MEDICAL DEVICE - Various techniques are provided for use with an implantable medical device for estimating cardiac pressure within a patient based on admittance (or related electrical values such as impedance or conductance) that takes into account the presence of acute MR within the patient. Briefly, the device detects an indication of acute MR, if occurring within the patient. The device also applies electrical fields to tissues of the patient and measures electrical parameters influenced by the electrical field, such as admittance, impedance or conductance. The device then estimates cardiac pressure within the patient based on the measured electrical parameter and the indication of acute MR. In one example, different linear correlation functions are used to convert admittance values to left atrial pressure (LAP) values depending upon the presence or absence of acute MR within the patient. | 02-09-2012 |
20120184859 | SYSTEMS AND METHODS FOR CORROBORATING IMPEDANCE-BASED LEFT ATRIAL PRESSURE (LAP) ESTIMATES FOR USE BY AN IMPLANTABLE MEDICAL DEVICE - Various techniques are provided for assessing the reliability of left atrial pressure (LAP) estimates made by an implantable medical device based on impedance values or related electrical values. In one example, various cardioelectric and cardiomechanical parameters are used to corroborate LAP estimation in circumstances where the LAP estimates deviate from an acceptable, satisfactory or otherwise healthy range. The cardioelectric parameters include, e.g.: ST elevation; heart rate (HR); heart rate variability (HRV); T-wave alternans (TWA); QRS waveform parameters; P-wave duration; evoked response (ER) parameters; and intrinsic PV/AV/VV conduction delays. The cardiomechanical parameters include, e.g.: heart rate turbulence (HRT); cardiogenic impedance signals; heart sounds; and non-LAP blood pressure measurements, such as aortic pressure measurements. The device compares the cardioelectric and cardiomechanical parameters against corresponding baseline values to determine whether variations in the parameters corroborate the LAP estimates. If not, the LAP estimates are selectively cancelled or suspended, or the overall procedure is re-calibrated. | 07-19-2012 |
20120271367 | DEVICES, SYSTEMS, AND METHODS FOR CHARACTERIZING A TACHYCARDIA AND/OR SELECTING TREATMENT FOR A TACHYCARDIA USING RESULTS OF A DOMINANT FREQUENCY ANALYSIS - Provided herein are implantable systems, and methods for use therewith, for characterizing a tachycardia and/or selecting treatment for a tachycardia using results of a dominant frequency analysis. One or more electrogram (EGM) signal(s) indicative of cardiac electrical activity are obtained. For at least one of the EGM signal(s) a dominant frequency (DF) analysis is performed, and the results of the DF analysis are used to characterize a tachycardia and/or to select treatment for a tachycardia. | 10-25-2012 |
20120271368 | DEVICES, SYSTEMS AND METHODS FOR CHARACTERIZING A TACHYCARDIA AND/OR SELECTING TREATMENT FOR A TACHYCARDIA USING RESULTS OF A FRACTIONATION ANALYSIS - Provided herein are implantable systems, and methods for use therewith, for characterizing a tachycardia and/or selecting treatment for a tachycardia using results of a fractionation analysis. One or more electrogram (EGM) signal(s) indicative of cardiac electrical activity are obtained. At least one of the EGM signal(s) is analyzed to determine whether the EGM signal is fractionated, and the results of the analyzing are used to characterize a tachycardia and/or to select treatment for a tachycardia. | 10-25-2012 |
20130030313 | METHODS AND SYSTEMS FOR ANALYZING T-WAVE ALTERNANS - Embodiments of the present invention relate to implantable systems, and methods for use therein, that can detect T-wave alternans and analyze the detected alternans to provide information regarding cardiac instabilities and predict impending arrhythmias. | 01-31-2013 |
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 |