Abstract: Systems and methods for monitoring pulmonary edema or other thoracic fluid status in a subject use thoracic impedance histogram information. An internal or external processor circuit receives the thoracic impedance histogram information and uses it to compute and provide a lung fluid status indication. The thoracic impedance histogram information can include a count, mean or median of a histogram bin or subrange of bins within the histogram range.

Abstract: The invention provides a system for measuring stroke volume (SV), cardiac output (CO), and cardiac power (CP) from a patient that features: 1) impedance sensor connected to at least two body-worn electrodes and including an impedance circuit that processes analog signals from the electrodes to measure an impedance signal (e.g. a TBEV waveform); 2) an ECG sensor connected to at least two chest-worn electrodes and including an ECG circuit that processes analog signals from the electrodes to measure and ECG signal; 3) an optical sensor connected to a body-worn optical probe and including an optical circuit that processes signals from the probe to measure at least one optical signal (e.g. a PPG waveform) from the patient; 4) a processing system, typically worn on the patient's wrist and connected through a wired interface to the optical sensor, and through either a wired or wireless interface to the TBEV and ECG sensors.

Abstract: A bio-impedance measurement apparatus includes a flexible band member fastened around a body portion, two probe sets attached to the flexible band member, a measurement device, and a wireless device. One probe set includes a probe having a tip portion for piercing the skin of the body portion to be located adjacent to an acupuncture point. Another probe set, used as an electrical ground, includes a probe that contacts the reference skin. The measurement device is disposed on the flexible band member and electrically coupled to the two probe sets to provide an impulse current signal to the acupuncture point. The measurement device amplifies and measures the voltage response across the acupuncture points and the ground. The amplified signal is converted to a digital signal for Fourier transformation. The wireless device, coupled to the measurement device, transmits the acupuncture code and impedance information to a remote monitor station.

Abstract: Methods and systems for determining information about a vascular bodily lumen are described. An exemplary method includes generating an electrical signal, delivering the electrical signal to a plurality of excitation elements in the vicinity of the vascular bodily lumen, measuring a responsive electrical signal from a plurality of sensing elements in response to the delivered electrical signal, and determining a lumen dimension. Specific embodiments include generating a multiple frequency electrical signal. Another embodiment includes measuring a plurality of responsive signals at a plurality of frequencies. Still other embodiments include using spatial diversity of the excitation elements. Yet other embodiments use method for calibration and de-embedding of such measurements to determine the lumen dimensions. Diagnostic devices incorporating the method are also disclosed, including guide wires, catheters and implants.

Abstract: Methods for determining the likelihood that a subject will be a placebo responder in a clinical study are provided. Also provided are methods for eliminating likely placebo responders from a clinical study a priori, thereby simplifying data analysis and minimizing or eliminating any confound that arises in the analysis as a result of placebo response. Databases and computer systems using the methods are also disclosed herein. Methods for assessing likelihood of a subject experiencing a response shift are also provided.

Abstract: A method and an arrangement for determining an overhydration parameter or a body composition parameter are disclosed. The method comprises: obtaining first bioimpedance measurement data of a patient from a first type of hioimpedance measurement (204), deriving bioimpedance calibration data from the first bioimpedance measurement data for calibrating second hioimpedance measurement data from a second type of bioimpedance measurement (205), obtaining the second bioimpedance measurement data from a second bioimpedance measurement of the patient (206), and calibrating the second bioimpedance measurement data using the calibration data to determine the overhydration parameter or the body composition parameter of the patient (207).

Abstract: A body fat measurement device includes hand electrodes that contact both hands, back area electrodes that contact the surface of a trunk area of the back, foot electrodes that contact both feet, a trunk area width detection unit for measuring the width and depth of the trunk area, a body impedance measurement unit that measures the body impedance of a body using the multiple electrodes and a body fat mass calculation unit that calculates a body fat mass based on the body impedance and the width and depth of the trunk area. The back area electrodes that make contact with the surface of the back of the trunk area are provided in a fitting unit in an exposed state, as well as the trunk area width detection unit. Accordingly, a body fat measurement device can measure a body fat mass easily and accurately in a household or the like.

Abstract: An implantable medical device system and associated method receive a signal from an implantable sensor operatively positioned relative to a vein, the signal being responsive to changes in a diameter of the vein. A diameter of the vein is determined in response to the sensor signal and used in estimating central venous pressure (CVP).

Abstract: An adherent device to monitor a patient for an extended period comprises a breathable tape. The breathable tape comprises a porous material with an adhesive coating to adhere the breathable tape to a skin of the patient. At least one electrode is affixed to the breathable tape and capable of electrically coupling to a skin of the patient. A printed circuit board is connected to the breathable tape to support the printed circuit board with the breathable tape when the tape is adhered to the patient. Electronic components electrically are connected to the printed circuit board and coupled to the at least one electrode to measure physiologic signals of the patient. A breathable cover and/or an electronics housing is disposed over the circuit board and electronic components and connected to at least one of the electronics components, the printed circuit board or the breathable tape.

Abstract: The present invention relates to a low-frequency stimulator using music, and a weight-loss assisting system having a low-frequency stimulator. The low-frequency stimulator according to an embodiment of the present invention includes: a beat extracting unit extracting a beat through a sound pressure magnitude comparison between one or more acoustic signals having different frequencies generated when music is played on a music player; a pulse generator generating a pulse having the same magnitude as that of the extracted beat; and a pair of electrode pads attached to a user's body and applying an electrical stimulus having an intensity corresponding to the magnitude of the generated pulse to the user's body.

Abstract: To assess regional oxygen uptake and/or perfusion in a patient, a volume of air inhaled by the patient is determined and, according to a method of electrical impedance tomography, a first regional lung volume is measured at a first time point of a breathold procedure. The first regional lung volume is compared to a second regional lung volume at a second time point of the breathold procedure.

Abstract: An activity meter includes an activity amount acquisition unit that acquires an amount of physical activity of a user, an activity age acquisition unit that acquires an activity age representing a standard age of a person who does a same amount of activity as the activity amount acquired in a unit period, using body information and a basal metabolic rate of the user, and an output processing unit that outputs information relating to the acquired activity age.

Abstract: The measuring and processing unit (20) of the invention comprises an electrical bioimpedance measuring sub-unit (9) and a processing sub-unit (10) for the discrete processing of measurements including a memory element for storing the measurements. The modular electrical bioimpedance measuring, processing and monitoring system comprises at least one of the aforementioned bioimpedance measuring and processing units (20). The modular system allows transmitting measurements to an external unit (30), such as a computer or PDA, for processing and/or monitoring. The bioimpedance data can be transmitted over the Internet or a GSM network from the external unit (30) to a remote unit for remote monitoring.

Abstract: An integrated device of a patch and sensor assembly detects extravasation or infiltration. A transmitter is positioned to direct power into a body portion. A sensor is positioned to receive the power transmitted through the body portion. A substrate is attachable to an outer surface of the body portion and supports the transmitter and the sensor. A signal processor is coupled to the transmitter and the sensor for detecting a change in a fluid level in the body portion from extravasation or infiltration based on the power received by the sensor. A power supply is coupled to the transmitter and the sensor. An indicator is responsive to the signal processor to indicate a detected change in a fluid level in the body portion from extravasation or infiltration.

Abstract: A system and method for guiding a catheter or other medical device to a desired target destination within the vasculature of a patient via bioimpedance measurements is disclosed. The target destination in one embodiment includes placement of the catheter such that a distal tip thereof is disposed proximate the heart, e.g., the junction of the right atrium and superior vena cava. In one embodiment the method for guiding the catheter comprises introducing the catheter into a vessel of the patient, the catheter defining a lumen through which fluids can be infused into the vasculature of the patient. The catheter is advanced toward a target destination within the vasculature. A first impedance value based on intravascular detection of at least one electrical property related to a first tissue surface of the vessel is calculated to enable determination of the proximity of a distal end of the catheter to the target destination.

Abstract: A method for scaling the impedance measured during the course of an electrophysiology study accounts for impedance drifts. By scaling the impedance there is greater assurance that previously recorded positional information can be used to accurately relocate an electrode at a prior visited position. The scale factor may be based upon a mean value across several sensing electrodes. Alternatively, the scale factor may be calculated specifically with respect to an orientation of a dipole pair of driven electrodes.

Abstract: Various methods and apparatuses for measuring a state parameter of an individual using signals based on one or more sensors are disclosed. In one embodiment, a first set of signals is used in a first function to determine how a second set of signals is used in one or more second functions to predict the state parameter. In another embodiment, first and second functions are used where the state parameter or an indicator of the state parameter may be obtained from a relationship between the first function and the second function. The state parameter may, for example, include calories consumed or calories burned by the individual. Various methods for making such apparatuses are also disclosed.

Abstract: A hydration monitoring apparatus is disclosed. The hydration monitoring apparatus comprises at least one sensor and an analysis unit. The hydration monitoring apparatus may take at least one biometric, biological, and/or physiological measurement of an individual and measures the hydration level, dehydration level or status, or bodily fluid level of an individual. The hydration monitoring apparatus indicates the hydration level, dehydration level or status, or bodily fluid level of an individual based on one or more biometric, biological, and/or physiological measurements. In one embodiment of the invention, the hydration monitoring apparatus determines whether to inform the user of their hydration level, dehydration level or status, or bodily fluid level. In one embodiment the hydration monitoring apparatus further comprises an informing device that informs the individual that the individual is approaching dehydration.

Abstract: Devices, systems, and methods to measure parallel tissue conductance, luminal cross-sectional areas, fluid velocity, and/or determine plaque vulnerability using temperature. In at least one embodiment of a method to obtain parallel tissue conductance, the method comprises the steps of inserting at least part of a detection device into a luminal organ, applying current thereto, obtaining a native temperature measurement, injecting a solution of a known conductivity into the luminal organ, detecting a temperature change indicative of the fluid within the luminal organ, measuring an output conductance, and calculating a parallel tissue conductance based upon the output conductance and the conductivity of the injected solution.

Abstract: A system and method for determining pulmonary performance from transthoracic impedance measures is provided. Transthoracic impedance measures collected by an implantable medical device are correlated to pulmonary functional measures. The pulmonary functional measures are grouped by respiratory pattern. Pulmonary performance is evaluated. Differences are determined by comparing the pulmonary functional measures for each respiratory pattern to the pulmonary functional measures for at least one previous respiratory pattern. A trend is identified from the differences. An alert is generated upon sufficient deviation of the trend from a threshold criteria.

Abstract: An adherent device to monitor a patient comprises an adhesive patch to adhere to a skin of the patient. At least four electrodes are connected to the patch and capable of electrically coupling to the patient. Impedance circuitry is coupled to the at least four electrodes to measure a hydration signal of the patient. Electrocardiogram circuitry is coupled to at least two of the at least four electrodes to measure an electrocardiogram signal of the patient. An accelerometer can be mechanically coupled to the adhesive patch to generate a signal in response to at least one of an activity or a position of the patient.

Abstract: Methods and systems for determining information about a vascular bodily lumen are described. An exemplary method includes generating an electrical signal, delivering the electrical signal to a plurality of excitation elements in the vicinity of the vascular bodily lumen, measuring a responsive electrical signal from a plurality of sensing elements in response to the delivered electrical signal, and determining a lumen dimension. Specific embodiments include generating a multiple frequency electrical signal. Another embodiment includes measuring a plurality of responsive signals at a plurality of frequencies. Still other embodiments include using spatial diversity of the excitation elements. Yet other embodiments use method for calibration and de-embedding of such measurements to determine the lumen dimensions. Diagnostic devices incorporating the method are also disclosed, including guide wires, catheters and implants.

Abstract: Various methods and apparatuses for measuring a state parameter of an individual using signals based on one or more sensors are disclosed. In one embodiment, a first set of signals is used in a first function to determine how a second set of signals is used in one or more second functions to predict the state parameter. In another embodiment, first and second functions are used where the state parameter or an indicator of the state parameter may be obtained from a relationship between the first function and the second function. The state parameter may, for example, include calories consumed or calories burned by the individual. Various methods for making such apparatuses are also disclosed.

Abstract: Systems and methods of detecting an impending cardiac decompensation of a patient measure at least two of an electrocardiogram signal of the patient, a hydration signal of the patient, a respiration signal of the patient or an activity signal of the patient. The at least two of the electrocardiogram signal, the hydration signal, the respiration signal or the activity signal are combined with an algorithm to detect the impending cardiac decompensation.

Abstract: An electrotherapeutic treatment system includes a portion of at least one skin or external contact element including an element for measurement of the bioreactance of biologically active neurological points (BANP) of a tissue or organ to be treated, monitoring of electromagnetic parameters received at the points and generating responsive corrective parameters; and a portion of a second electrode for neurologically transmitting bioreactive parameters proximally to a BANP of tissues or organs to be treated, the parameters modifying discrete reactive values responsive to those measured by each of the first or second electrodes responsive to abnormal parameters received from tissues or organs to be treated at or between the BANP.

Abstract: 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.

Abstract: The mental state of an individual is obtained to determine their well-being status. The mental state is derived from an analysis of facial information and physiological information of an individual. The well-being status of other individuals is correlated to the well-being status of the first individual. The well-being status of the individual or group of individuals is rendered for display. The well-being status of an individual is used to provide feedback and to recommend activities for the individual.

Abstract: A medical probe includes an elongate member having a proximal end and a distal end, an ablative element mounted to the distal end of the elongate member, and a cage assembly mounted to the distal end of the elongate member, the cage assembly at least partially covers the ablative element. A method of treating tissue in a body includes inserting an ablative element in the body, placing the ablative element adjacent the tissue, and maintaining a distance between the ablative element and the tissue using a protective catheter element that circumscribes at least a portion of the ablative element.

Abstract: Impedance devices and methods of using the same to obtain luminal organ measurements. In at least one embodiment of an impedance device of the present disclosure, the impedance device comprises an elongated body having a distal body end, and a first electrode located along the elongated body at or near the distal body end, the first electrode configured to obtain one or more conductance values within a mammalian luminal organ within an electric field, wherein a measured parameter of the mammalian luminal organ can be calculated based in part upon the one or more conductance values obtained by the first electrode.

Abstract: Methods, systems, and apparatus for assessing a state of a comorbidity associated with a primary disease are provided. The methods comprise receiving at least one autonomic index, neurologic index, stress marker index, psychiatric index, endocrine index, adverse effect of therapy index, physical fitness index, or quality of life index of a patient; comparing the at least one index to at least one reference value; and assessing a state of a body system of the patient that is a site of the comorbidity, based on the comparison. A computer readable program storage device encoded with instructions that, when executed by a computer, perform the method described above is also provided. A medical device system capable of implementing the method described above is also provided.

Abstract: An implanted device-implemented method of detecting and monitoring congestive heart failure in a patient includes performing ongoing measurements of changes in local impedance of a portion of the patient's body between at least two electrodes on the exterior of the implanted device, the changes representing ventilation of the patient, and including measuring the patient's respiratory rate and respiratory amplitude. A body-implantable device is adapted to detect and monitor congestive heart failure in a patient, and includes a circuit module coupled to plural surface electrodes of the device arranged and adapted, when the device is implanted, for contacting tissue in a portion of the patient's body generally occupied by the lungs, to monitor changes in local impedance of said body portion, and to detect the patient's EKG.

Abstract: A method of monitoring pulmonary oedema in a subject using a processing system. The method includes, determining a measured impedance value for at least two body segments, at least one of the body segments being a thoracic cavity segment. For each body segment, the measured impedance values are used to determine an index, which is in turn used to determine the presence, absence or degree of pulmonary oedema using the determined indices.

Abstract: A method of monitoring a biosignal includes receiving a biosignal and a reference signal, determining a signal state of the biosignal based on the reference signal, and analyzing the biosignal using an analysis technique having a resource consumption depending on the signal state.

Abstract: An physiological data acquisition apparatus includes three or more leads, at least one AC current source, a switching mechanism structured to selectively couple the current source to selected lead pairs to inject an AC current across the selected lead pairs which produces an AC voltage across the selected lead pair, and a processing device. The processing device is structured to (i) determine an impedance across the current selected lead pair based on the AC voltage, (ii) determine whether the impedance is less than a predetermined threshold, (iii) if the impedance is less than the predetermined impedance threshold cause the current selected lead pair to be used for generating physiological parameter data, and (iv) if the impedance is not less than the threshold cause the switching mechanism to couple the at least one AC current source to a new selected pair of the leads.

Abstract: The invention provides an electrophysiological analysis system, in particular for detecting pathological states. This system comprises: electrodes intended to be placed in different regions of the body that are well away from each other; an adjustable DC voltage source for generating successive DC voltage pulses varying in magnitude from one pulse to another, the duration of the pulses being equal to or greater than about 0.2 seconds; a switching circuit for selectively connecting a pair of active electrodes to the voltage source and for connecting at least one other high-impedance electrode; and a measurement circuit for recording data representative of the current in the active electrodes and potentials on at least certain high-impedance connected electrodes in response to the application of said pulses. The range of voltages covered causes, from one pulse to another, the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes.

Abstract: A temperature sensor for detecting heating of at least one electrode pole of a temporarily or permanently implantable electrode line or a similar implant having at least one elongated electrical conductor which is connected to at least one electrode pole. The temperature sensor has an impedance detecting unit or is connected to one and is configured for evaluating an electrode pole impedance detected by the impedance detecting unit in such a manner that the evaluation takes place with respect to a temperature-dependent feature of the electrode impedance. The impedance detecting unit is electrically connected to the at least one electrode pole or is configured and arranged to be electrically connected to the at least one electrode pole.

Abstract: A conductivity sensor is disclosed. The conductivity sensor includes an oscillator for providing an input signal and a reactive circuit having an induction coil, a capacitive element, and a resistive element connected in parallel. The induction coil is adapted to be placed adjacent to a specimen. The conductivity sensor further includes a control circuit for driving the reactive circuit to resonance when the induction coil is placed adjacent to the specimen. The reactive coil is configured to provide an output signal having a parameter representative of the conductivity of the specimen when the reactive circuit is at resonance. The induction coil may include a first conductive element that spirals outward to an external perimeter and a second conductive element operably connected to the first conductive element. The second conductive element spirals inward from the external perimeter staggered relative to the first conductive element.

Abstract: A manually operated pedicle locator instrument measures the static permittivity of matter to locate pedicles in vertebral or bony structures. The locator senses and compares the dielectric constants of the pedicle and the surrounding matter. When the operative component of the locator, the component which contains controlled capacitors, is placed over non-pedicle material, the locator will sense one dielectric constant. However, when it is placed over a pedicle, there is a different dielectric constant. The locator operates on this capacitance difference generated by differences in density. Circuitry in the locator senses this change and sends the change signal to indicator lights located on the locator. A switch on the locator allows the surgeon to select different levels of capacitance in order to identify thicknesses of different bony structures, i.e. structures in cervical, thoracic, and lumbar vertebral bodies.

Abstract: A method of determining the conductance of the skin of a human or animal, the method including the step of: (a) eliminating any equivalent parasitic voltages in the skin by taking multiple different measurements of the conductance utilizing different probe voltage levels, (b) calculating the conductance from the sampled results of the multiple different measurements.

Abstract: The invention provides a sensor for measuring both impedance and ECG waveforms that is configured to be worn around a patient's neck. The sensor features 1) an ECG system that includes an analog ECG circuit, in electrical contact with at least two ECG electrodes, that generates an analog ECG waveform; and 2) an impedance system that includes an analog impedance circuit, in electrical contact with at least two (and typically four) impedance electrodes, that generates an analog impedance waveform. Also included in the neck-worn system are a digital processing system featuring a microprocessor, and an analog-to-digital converter. During a measurement, the digital processing system receives and processes the analog ECG and impedance waveforms to measure physiological information from the patient. Finally, a cable that drapes around the patient's neck connects the ECG system, impedance system, and digital processing system.

Abstract: [Object] To provide a biosignal measurement apparatus capable of measuring a contact resistance with high accuracy. [Solving Means] A biosignal measurement apparatus according to the present technology includes a voltage supply, a measurement electrode, a resistor, a first amplifier, and a neutral electrode. The measurement electrode is connected to the voltage supply and brought into contact with a living body. The resistor is connected between the voltage supply and the measurement electrode. The first amplifier amplifies a potential between the resistor and the measurement electrode. The neutral electrode is brought into contact with the living body.

Abstract: An EIT system (1) adapted to detect internal bleeding in a body portion, the EIT system (1) comprising a plurality of electrodes (3) adapted in use to extend in a substantially linear orientation across one side only of the body portion and to be applied in electrical contact with the skin of the body portion, a current source adapted to cyclically apply an electric current between one pair of the electrodes (3), a voltage measuring means to measure the voltage across each of the other pairs of the electrodes resulting from the current, a data collection system (2) and a data analysis system (4) to analyze data resulting from the voltages that are measured by the voltage measuring means, wherein the analysis system (4) is configured to obtain quantitative information related to amounts and rates of conductive tissue changes occurring in the body, based on an EIT analysis equivalent to that obtained from data derived from electrodes spaced around the full perimeter of the body portion.

Abstract: A medical device having an impedance measurement circuit connected to at least two intracorporeal measurement electrodes arranged to measure the impedance of tissue inside the body of a patient. The impedance measurement circuit is adapted to apply a measurement current/voltage signal to the electrodes to measure and calculate the impedance of the measurement tissue, and to apply the calculated impedance value to a storage unit. The stored impedance values are used, by an analysis unit, to measure the amount of visceral fat of the tissue object inside the body of the patient.

Abstract: A method of determining frequencies for use in performing impedance measurements. The method includes determining estimates for parameter values representing an impedance response for at least one subject, using the estimated parameter values to determine a design and using the design to determine frequencies for use in impedance measurements.

Abstract: An apparatus for determining a thermal property of tissue includes a base unit with one or more energy source and at least two, preferably detachable, leads. The distal end of each lead, which is introduced into the tissue to be treated, has at least two longitudinally spaced temperature measuring elements to measure surrounding tissue temperature and at least two longitudinally spaced electrode surfaces for applying current to the tissue. Each distal end is also provided with an element which uses energy emitted by the sources of energy to heat up the surrounding tissue. The base unit has computing elements, current generating elements for generating an alternating current, and conductance determining elements for determining the tissue conductance between pairs of electrode surfaces based on the alternating current applied by the current generating elements to the tissue. Methods for using the device and leads for use in the device are also described.

Abstract: Disclosed herein is an insertable probe for diagnosis of lesional tissue in real time. The insertable probe includes a guide needle inserted into the human body and having a hollow shape of a predetermined length, a storage connected to the guide needle, a tissue collection portion collecting a predetermined amount of tissue in the human body and moving the collected tissue to the storage through the guide needle, and an inspection unit inspecting the tissue stored in the storage. A method of manufacturing an electrode using the same is also disclosed.

Abstract: According to various embodiments, a system, method, and sensor are provided that is capable of monitoring electrical impedance of oral or nasal mucosal tissue. Such sensors may be appropriate for assessing gut hypoperfusion, gut ischemia, or the onset of shock. The electrical impedance of the oral mucosa or other tissues in the upper respiratory tract may be used to non-invasively assess the clinical state of gastrointestinal tissue.

Abstract: Techniques are provided for use with an implantable medical device for detecting and assessing heart failure and for controlling cardiac resynchronization therapy (CRT) based on impedance signals obtained using hybrid impedance configurations. The hybrid configurations exploit right atrial (RA)-based impedance measurement vectors and/or left ventricular (LV)-based impedance measurement vectors. In one example, current is injected between the device case and a ring electrode in the right ventricle (RV) or RA. RA-based impedance values are measured along vectors between the device case and an RA electrode. LV-based impedance values are measured along vectors between the device case and one or more electrodes of the LV. Heart failure and other cardiac conditions are detected and tracked using the measured impedance values. CRT delay parameters are also optimized based impedance.

Abstract: Methods and apparatus combine patient measurement data with demographic or physiological data of the patient to determine an output that can be used to diagnose and treat the patient. A customized output can be determined based the demographics of the patient, physiological data of the patient, and data of a population of patients. In another aspect, patient measurement data is used to predict an impending cardiac event, such as acute decompensated heart failure. At least one personalized value is determined for the patient, and a patient event prediction output is generated based at least in part on the personalized value and the measurement data. For example, bioimpedance data may be used to establish a baseline impedance specific to the patient, and the patient event prediction output generated based in part on the relationship of ongoing impedance measurements to the baseline impedance. Multivariate prediction models may enhance prediction accuracy.

Abstract: An implantable medical device comprises a signal generator for generating a current signal having a frequency in a frequency window slightly less than the ?-dispersion frequency of a tissue and applying the signal over the tissue. A signal measurer measures the resulting voltage signal and an impedance parameter is calculated from the applied and measured signal by a parameter determiner. A status monitor monitors the permeability status of cell membranes in the tissue based on this impedance parameter.