Patent application number | Description | Published |
20090093857 | SYSTEM AND METHOD TO EVALUATE ELECTRODE POSITION AND SPACING - An IMD can be implanted into a patient to address various conditions. The IMD case and leads can have various electrodes and other portions to measure various physiological conditions. For example, a selected current can be generated between two electrodes, either external or internal in the patient, and a voltage can be measured by one or more electrodes of the IMD. A voltage can be measured at two or more locations to determine a relative motion of different electrodes. If the electrodes are in different portions of the heart, a determination can be made of a relative motion or position of the heart or portions of the heart. | 04-09-2009 |
20090270933 | Pressure and Impedance Based Discrimination of Hemodynamic Stability - An implantable cardioverter defibrillator evaluates the hemodynamic stability of an arrhythmia to determine whether or not to defibrillate. The device obtains cardiac pressure and cardiac impedance data and evaluates a phase relationship between these parameters. Hemodynamically stable rhythms will result in an out of phase relationship. | 10-29-2009 |
20090270934 | Pressure and Impedance Based Discrimination of Hemodynamic Stability - An implantable cardioverter defibrillator evaluates the hemodynamic stability of an arrhythmia to determine whether or not to defibrillate. The device obtains cardiac pressure and cardiac impedance data and evaluates a phase relationship between these parameters. Hemodynamically stable rhythms will result in an out of phase relationship. | 10-29-2009 |
20090275854 | SYSTEM AND METHOD OF MONITORING PHYSIOLOGIC PARAMETERS BASED ON COMPLEX IMPEDANCE WAVEFORM MORPHOLOGY - Changes in physiologic parameters may be detected in a patient by measuring the impedance of a tissue segment located in a selected electrode vector field, storing baseline impedance information based on the measured impedance, detecting changes in impedance characteristics from the baseline impedance information, and providing alerts for changes in the physiologic parameters based on the detected changes in impedance characteristics. In some situations, detecting the changes in impedance characteristics involves detecting changes in morphology of an impedance waveform, such as a cardiac component of an impedance waveform, a respiratory component of an impedance waveform, and the phase angle of the complex impedance. | 11-05-2009 |
20090275855 | MULTI-FREQUENCY IMPEDANCE MONITORING SYSTEM - A system and method is provided to measure intrathoracic complex impedance and to identify and indicate disease conditions based on the impedance measurements. Multiple impedance vectors may betaken into account, and an optimal vector may be selected to provide the most useful impedance measurement for the identification and indication of disease conditions. | 11-05-2009 |
20100023079 | Cardiac Pacing Methods and Apparatus - A method and apparatus is provided for determining whether a current atrial-ventricular (AV) delay during cardiac pacing is appropriate for proper mechanical coupling of the atrium and ventricle. If proper mechanical coupling is determined to not exist, an additional atrial contraction is induced within the same ventricular cycle to maintain atrial-ventricular mechanical coupling. | 01-28-2010 |
20100030086 | MONITORING HEMODYNAMIC STATUS BASED ON INTRACARDIAC OR VASCULAR IMPEDANCE - This disclosure relates to monitoring intracardiac or vascular impedance to determine a change in hemodynamic status by detecting changes in an impedance parameter over cardiac cycles. An example method includes measuring a plurality of impedance values of a path within a patient over time, wherein the path includes at least one blood vessel or cardiac chamber of the patient, and wherein the impedance values vary as a function of blood pressure within the at least one vessel or chamber, determining a plurality of values of an impedance parameter over time based on the measured impedance values, wherein each of the impedance parameter values is determined based on a respective sub-plurality of the impedance values, comparing at least one of the impedance parameter values to at least one prior impedance parameter value, and identifying a change in a cardiovascular parameter related to the blood pressure based on the comparison. | 02-04-2010 |
20100030087 | ESTIMATING CARDIOVASCULAR PRESSURE AND VOLUME USING IMPEDANCE MEASUREMENTS - Techniques for estimating a cardiac chamber or vascular pressure based upon impedance are described. A device or system may measure an impedance between at least two electrodes implanted within or proximate to a cardiovascular system. The device or system may estimate a pressure of an element of the cardiovascular system based on a relationship between impedance and volume of the element, and based on a empirical relationship between the volume and the pressure. The device or system may also estimate the dimension of the element based on the impedance-volume relationship, or other characteristics based on the impedance. Because the impedance measurements may be obtained, in some examples, by using electrodes and leads implanted within the cardiovascular system and coupled to an implantable medical device, a practical estimation of a cardiovascular pressure can be obtained on a chronic basis without requiring the use other invasive sensors, such as micronanometer transducers. | 02-04-2010 |
20100030292 | DETECTING WORSENING HEART FAILURE BASED ON IMPEDANCE MEASUREMENTS - Techniques for processing impedance data to provide an early warning for heart failure decompensation are described. An example device may be configured to measure intrathoracic impedance values, and increment an index when a determined impedance is less than a reference impedance. The incrementing may be based on the difference between the reference impedances and the determined impedance. In some examples, the amount of incrementing is reduced based on a variability of the impedances, or increased over time so long as the index remains above a threshold, e.g., zero. In some examples, the manner is which the reference impedances are determined changes over time to, for example, address rapid changes in impedance after device or system implantation. In some examples, the index is compared to a threshold to determine whether to provide an alert. In some examples, two thresholds are used to provide hysteresis. | 02-04-2010 |
20100030293 | USING MULTIPLE DIAGNOSTIC PARAMETERS FOR PREDICTING HEART FAILURE EVENTS - Techniques for using multiple physiological parameters to provide an early warning for worsening heart failure are described. A medical device monitors a primary diagnostic parameter that is indicative of worsening heart failure, such as intrathoracic impedance or pressure, and one or more secondary diagnostic parameters. The medical device detects worsening heart failure in the patient based on the primary diagnostic parameter when an index that is changed over time based on the primary diagnostic parameter value is outside a range of values, termed the threshold zone. When the index is within the threshold zone, the medical device detects worsening heart failure in the patient based on the one or more secondary diagnostic parameters. Upon detecting worsening heart failure, the medical device may, for example, provide an alert that enables the patient to seek medical attention before experiencing a heart failure event. | 02-04-2010 |
20100069982 | TIME BASED ARRHYTHMIA THERAPY EFFICACY CRITERIA - An implantable medical device and associated method classify therapy outcomes and heart rhythms in association with therapy outcome. A therapy success time interval is started in response to delivering an arrhythmia therapy. If normal sinus rhythm is detected after the therapy success time interval expires, the delivered therapy is classified as unsuccessful and the detected arrhythmia is classified as a self-terminating rhythm. | 03-18-2010 |
20100113888 | HEART FAILURE DECOMPENSATION DETERMINATION - Heart failure decompensation is detected by sensing at least one physiological signal. Values of at least two different heart failure variables are derived using one or more physiological signals and a threshold for the first heart failure variable is adjusted in response to the value of the second heart failure variable. The value of the first heart failure variable is compared to first threshold for detecting a heart failure condition. | 05-06-2010 |
20100113962 | SYSTEM AND METHOD TO LOCALIZE CHANGES IN INTRATHORACIC FLUID CONTENT USING MEASURED IMPEDANCE IN AN IMPLANTABLE DEVICE - An implantable medical device and associated methods monitor thoracic fluid status and discriminate thoracic fluid conditions. Intrathoracic impedance is measured along multiple intrathoracic measurement vectors using implanted electrodes. A map of thoracic conductivity is computed using the measured intrathoracic impedances. A thoracic fluid condition is detected in response to the computed map. | 05-06-2010 |
20110029034 | ALGORITHM TO MODULATE ATRIAL-VENTRICULAR DELAY AND RATE RESPONSE BASED ON AUTONOMIC FUNCTION - An implantable medical device and associated method provide atrial pacing and measure an atrial ventricular (AV) delay. An autonomic function index is computed using the AV delay. The autonomic function index may be compiled in a medical report. In some embodiments, the autonomic function index is used to adjust atrial pacing control parameters. | 02-03-2011 |
20110190654 | QUANTIFYING AUTONOMIC TONE WITH THORACIC IMPEDANCE - The disclosure describes techniques for quantifying the autonomic nervous system (ANS) health of a patient with thoracic impedance measurements. Thoracic impedance may be measured utilizing cardiac electrodes and an implantable medical device housing or other electrodes located on or within the patient. Since greater variability in thoracic impedance may indicate better health of the ANS, monitoring impedance changes in a patient may be used to quantify autonomic tone of the ANS, and ultimately, overall patient health. In some examples, thoracic impedance may be measured in response to a change in patient posture for acute monitoring or at predetermined times over several days, weeks, or months for more chronic monitoring of the patient. An implantable medical device may independently analyze the impedance measurements and transmit an alert to the patient or clinician when impedance changes indicate a change in patient health. | 08-04-2011 |
20120004566 | SYSTEM AND METHOD FOR ESTABLISHING EPISODE PROFILES OF DETECTED TACHYCARDIA EPISODES - A medical device and associated method sense a cardiac signal and initiate an arrhythmia episode detection process in response to the cardiac signal by enabling an arrhythmia detection counter to be adjusted during the detection process. Data is accumulated relating to cardiac events during the detection process. An arrhythmia episode profile is established using the accumulated data. The accumulated data includes a pattern of the adjustment of the detection counter during the detection process | 01-05-2012 |
20120109243 | HEART FAILURE MONITORING AND NOTIFICATION - Techniques for generating a heart failure risk score with detected patient metrics are described. An implantable medical device (IMD) may collect and store patient data regarding therapy use statistics, thoracic impedance, heart rate, patient activity, and other patient metrics. Based on the number of patient metrics exceeding their respective metric thresholds, the IMD may automatically generate a risk score that indicates the likelihood that the patient will suffer from heart failure. The risk score may identify a patient as requiring immediate medical attention to reduce the risk of heart failure. The IMD may push an alert of the heart failure risk score to a clinician, and the clinician may review the patient metric data on an external device. In some examples, a clinician may prioritize patient treatment with a presented list ranking patients with the most severe heart failure risk scores. | 05-03-2012 |
20120109245 | CARDIAC THERAPY BASED UPON IMPEDANCE SIGNALS - Methods and/or devices are disclosed herein for monitoring cardiac impedance signal and delivering therapy to a patient's heart based upon the monitored cardiac impedance. | 05-03-2012 |
20120150049 | IMPEDANCE MEASUREMENT TO MONITOR ORGAN PERFUSION OR HEMODYNAMIC STATUS - An implantable medical device system and associated method deliver drive signals having different frequencies to establish vector fields comprising an arterial volume and a venous volume corresponding to targeted portion of a patient's body. Impedance signals are determined in response to drive signals having different frequencies. Impedance parameter values are determined over time. A change in the hemodynamic status of a targeted portion of the patient's body is identified in response to the impedance parameter values. | 06-14-2012 |
20120150169 | IMPEDANCE MEASUREMENT TO MONITOR ORGAN PERFUSION OR HEMODYNAMIC STATUS - A system and method for deliverying an ablation therapy that includes delivering the ablation therapy, delivering drive signals to establish a drive signal vector fields, determining impedance signals in response to the drive signals, determining a first impedance parameter in response to the first impedance signal and a second impedance parameter in response to the second impedance signal, determining whether there is a change in a hemodynamic status of the tissue subsequent to delivery of the ablation therapy in response to the first impedance parameter and the second impedance parameter, and adjusting delivery of the ablation therapy in response to determining whether there is a change in a hemodynamic status of the tissue. | 06-14-2012 |
20120253207 | HEART FAILURE MONITORING - Techniques for transmitting diagnostic information stored in an implantable medical device (IMD) based on patient hospitalization are described. For example, the IMD may transmit higher resolution diagnostic information to a clinician and/or an external device during a hospitalization period to aid the clinician in evaluating heart failure treatment and when discharge is proper. This higher resolution diagnostic information may include one or more patient metrics automatically generated and transmitted by the IMD at least once every two hours. During a post-hospitalization period, the IMD may transmit lower resolution diagnostic information to a clinician that indicates a risk level of re-hospitalization. The lower resolution diagnostic information may include the risk level and/or patient metrics once a day, for example. In this manner, the IMD transmitted diagnostic information may be tailored to the specific heart failure monitoring needed by the patient. | 10-04-2012 |
20120303085 | METHODS AND APAPRATUS FOR MANUALLY SUSPENDING INTRATHORACIC IMPEDANCE FLUID STATUS MEASUREMENTS - The capability to suspend a patient alert relating to a monitored physiologic parameters addresses a need to selectively shut off a patient-alert signal or signals during the time a patient is being treated for an excursion in the parameter. Of course, in general a signal call attention to a patient's a potentially deleterious status or condition for which they should seek medical attention. Once a chronically-implanted monitoring device has detected or provided information about the parameter relative to a desired value, trend, or range and a clinician has been notified and intervened the alert signal is temporarily disabled for a predetermined period. That is, once the notification occurs and alert has served its purpose, the alert mechanism is selectively deactivated while the patient ostensibly begins to gradually correct the monitored physiologic parameter under a caregiver's direction and control. After which time, the alert will reactivate. | 11-29-2012 |
20130030319 | CARDIAC MONITORING USING SPINAL CORD STIMULATION ELECTRODES - Methods and systems for use in cardiac monitoring may periodically measure intrathoracic impedance using one or more pairs of electrodes and analyze measured impedance values to identify changes in the patient's thoracic fluid content for use in cardiac monitoring. The intrathoracic impedance is measured using at least one spinal cord stimulation electrode. | 01-31-2013 |
20130110188 | METHOD TO ASSESS HEMODYNAMIC PERFORMANCE DURING CARDIAC RESYNCHRONIZATION THERAPY OPTIMIZATION USING ADMITTANCE WAVEFORMS AND DERIVATIVES | 05-02-2013 |
20130110190 | METHOD TO ASSESS HEMODYNAMIC PERFORMANCE DURING CARDIAC RESYNCHRONIZATION THERAPY OPTIMIZATION USING ADMITTANCE WAVEFORMS AND DERIVATIVES | 05-02-2013 |
20130197385 | RESPIRATORY FUNCTION DETECTION - A method and system for monitoring respiratory function that includes an impedance sensor configured to sense a first thoracic impedance waveform for at least one breath of a patient, a memory configured to store a first threshold slope value, and a processor configured to determine an first breath slope value in response to the impedance waveform, compare the first breath slope value to a first threshold slope value, and determine an indication of respiratory function of the patient in response to the comparing. | 08-01-2013 |
20130197386 | RESPIRATORY FUNCTION DETECTION - A system and method for monitoring respiratory function that includes an acoustic sensing device sensing an acoustic waveform ocurring during one of an inspiration phase associated with at least one breath of a patient and an expiration phase associated with at least one breath of a patient, and a processor configured to determine changes in high frequency acoustic amplitude associated with the sensed acoustic waveform and, in response to the determined changes in high frequency acoustic amplitude, determine an indication of respiratory function. | 08-01-2013 |
20140142646 | CARDIAC THERAPY BASED UPON IMPEDANCE SIGNALS - Methods and/or devices are disclosed herein for monitoring cardiac impedance signal and delivering therapy to a patient's heart based upon the monitored cardiac impedance. | 05-22-2014 |
20140288455 | MULTI-FREQUENCY IMPEDANCE MONITORING SYSTEM - A system and method is provided to measure intrathoracic complex impedance and to identify and indicate disease conditions based on the impedance measurements. Multiple impedance vectors may be taken into account, and an optimal vector may be selected to provide the most useful impedance measurement for the identification and indication of disease conditions. | 09-25-2014 |