摘要:
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.
摘要:
A method for trending heart failure measures cardiogenic impedance (CI) and obtains 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 signals and applies the correction factors to the contractility estimates. A system for trending heart failure includes a contractility module to determine contractility estimates from CI measurements taken along at least a first vector through a heart, and a collection module to receive 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 system further includes a factor module to identify correction factors based on the signals and a correction module to apply the correction factors to the contractility estimates.
摘要:
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.
摘要:
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.
摘要:
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.)
摘要:
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.)
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.