Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A pressure sensor is deployed in the right atrium and is in contact with the tissue of the fossa ovalis. The fossa ovalis acts as a membrane and the pressure sensor determines the relative and/or absolute pressure within the left atrium while remaining within the right atrium. A variety of embodiment are provided to deploy and anchor the sensor into the proper position.

Abstract: An implantable medical device and associated method detect obstructed inspiration by monitoring an blood pressure signal. A respiration signal is monitored and a phase of respiratory inspiration is detected from the respiration signal. A trend in the pressure signal is measured during the inspiration phase. Obstructed inspiration for the inspiration phase is detected in response to the measured the trend.

Abstract: A pressure sensor is deployed in the right atrium and is in contact with the tissue of the fossa ovalis. The fossa ovalis acts as a membrane and the pressure sensor determines the relative and/or absolute pressure within the left atrium while remaining within the right atrium. A variety of embodiment are provided to deploy and anchor the sensor into the proper position.

Abstract: A pressure sensor is deployed in the right atrium and is in contact with the tissue of the fossa ovalis. The fossa ovalis acts as a membrane and the pressure sensor determines the relative and/or absolute pressure within the left atrium while remaining within the right atrium. A variety of embodiment are provided to deploy and anchor the sensor into the proper position.

Abstract: A pressure sensor is deployed in the right atrium and is in contact with the tissue of the fossa ovalis. The fossa ovalis acts as a membrane and the pressure sensor determines the relative and/or absolute pressure within the left atrium while remaining within the right atrium. A variety of embodiment are provided to deploy and anchor the sensor into the proper position.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: According to the invention, methods and devices for increasing cardiopulmonary circulation induced by chest compression and decompression when performing cardiopulmonary resuscitation are provided. According to one method, a pressure responsive inflow valve is coupled to a patient's airway. Chest compressions and chest decompressions are performed. During chest decompression the inflow valve prevents respiratory gases from entering the lungs until a certain negative intrathoracic pressure level is exceeded at which time the one inflow valve opens. In this way, the inflow valve assists in increasing the magnitude and duration of negative intrathoracic pressure during decompression to enhance the amount of blood flow into the heart and lungs. Further, the patient is supplied with a pressurized respiratory gas through the inflow valve when the inflow valve opens to ventilate the patient.

Abstract: In an implantable medical device a real-time left atrial pressure (“LAP”) signal obtained from a patient's heart is used as a feedback control mechanism to adjust one or more device parameters. In one example the device identifies specific characteristics and attributes of the LAP signal that correlate to hemodynamic performance, and adjusts the device parameters to optimize the LAP characteristics and attributes. In a dual-chamber pacing system, the controlled operating parameter may include the atrioventricular pacing delay, and LAP attribute suitable for controlling the atrioventricular pacing delay time intervals of v-wave, a-wave, and/or c-wave characteristics of the LAP signal.