Abstract: A system for presenting information representative of patient electrophysiological activity, such as complex fractionated electrogram information, includes at least one electrode to measure electrogram information from the heart surface, at least one processor coupled to the at least one electrode to receive the electrogram information and measure a location of the at least one electrode within the heart, and a presentation device to present the electrogram information as associated with the location at which it was measured on a model of the patient's heart. A memory may also be provided in which to store the associated electrogram information and measured location. Data may be analyzed using both time-domain and frequency-domain information to create a three-dimensional map. The map displays the data as colors, shades of color, and/or grayscales, and may further utilize contour lines, such as isochrones, to present the information.

Abstract: Disclosed herein are methods and devices for delivering gas to a subject and obtaining plethysmograph readings from a subject. Specifically disclosed herein are masks and helmets which comprise one or more pulse oximeter probes associated therewith. The masks and helmets may be used in particular contexts, including, but not limited to, emergency responder personnel, pilots or subjects of medical attention.

Abstract: A garment for ambulatory, physiological monitoring of a patient includes a belt, having first and second end portion with closures at the end portions to wrap around a user's chest, a strap having a first end coupled to a portion of the belt with the strap having a second end, a pair of shoulder strap portions each shoulder strap portion having a first end coupled together at the second end of the strap and a second end, and a back portion that joins the second ends of the pair of shoulder strap portions, with at least one of the belt, strap portions and back portion having an accommodation for carrying a sensor. Other embodiments are described.

Abstract: Systems and Methods for predicting patient health and patient relative well-being within a patient management system are disclosed. A preferred embodiment utilizes an implantable medical device comprising an analysis component and a sensing component further comprising a three-dimensional accelerometer, a transthoracic impedance sensor, a cardio-activity sensor, an oxygen saturation sensor and a blood glucose sensor. Some embodiments of a system disclosed herein also can be configured as an Advanced Patient Management System that helps better monitor, predict and manage chronic diseases.

Abstract: Methods and systems are disclosed for determining information about a position of an object within a distribution of materials having different complex conductivities. The method includes: (i) causing current to flow in the distribution; (ii) measuring an electrical signal at each of multiple locations in the distribution of materials in response to the current flow; (iii) providing spatial information about the distribution of materials with respect to a first reference frame, the spatial information indicative of regions of different complex conductivity in the distribution of materials; and (iv) determining the position of the object with respect to the spatial information about the distribution of materials based on measured electrical signals and the spatial information. In certain embodiments, the object is a catheter inserted into a patients heart cavity for cardiac mapping.

Abstract: The invention provides a method and an apparatus for a continuous non-invasive and non-obstrusive monitoring of blood pressure. The method comprises the steps of: a) measuring the value (PW) of a Pulse Wave parameter, equal to or derived from the Pulse Wave Velocity (PWV) parameter of a segment of the arterial tree of a subject, b) measuring the value (CO) of the Cardiac Output parameter, and c) determining the value (BP) of the blood pressure that satisfies B ? ? P = arg ? ? min BP ? ? d ? ( P ? ? W , ? ( C ? ? O , B ? ? P ) ) , where PW is the value measured in step a), (CO, BP) corresponds to a predicted value of the Pulse Wave parameter computed according to a model of the segment of the arterial tree, the value (CO) of the Cardiac Output parameter measured in step b) and an hypothesized value of the blood pressure.

Abstract: An implantable medical device has an impedance determiner for determining a cardiogenic impedance signal based on electric signals sensed by connected electrodes. A parameter calculator processes the impedance signal to calculate an impedance parameter representative of the cardiogenic impedance in connection with the diastolic phase of a heart cycle. This parameter is then employed by the device for monitoring acute decompensated heart failure status of a subject.

Abstract: A method of predicting onset of electromechanical dissociation in a heart of a subject is disclosed. The method comprises: extracting from the composite input signal an electrocardiac signal and determining electrical activity of the heart based on the electrocardiac signal; extracting from the composite input signal a radiofrequency signal and determining blood flow measure based on the radiofrequency signal; and if the blood flow measure is below a predetermined threshold and the electrical activity is above a predetermined threshold, then predicting the onset of electromechanical dissociation.

Abstract: A method of estimating cerebral blood flow by analyzing IPG and PPG signals of the head, the method comprising: a) finding a maximum slope or most negative slope or the IPG signal, within at least a portion of the cardiac cycle; b) finding a maximum slope or most negative slope of the PPG signal, within at least a portion of the cardiac cycle; c) finding a ratio of the maximum or most negative slope of the IPG signal to the maximum or most negative slope of the PPG signal; and d) calculating a cerebral blood flow indicator from the ratio.

Abstract: An apparatus including an input interface configured to provide signals from at least two sensors for at least two postures including: signals, dependent upon blood presence, from a first sensor when a subject is in a first posture; signals, dependent upon blood presence, from the first sensor when the subject is in a second posture; signals, dependent upon blood presence, from a second sensor when the subject is in the first posture; and signals, dependent upon blood presence, from the second sensor when the subject is in the second posture; and processing circuitry configured to determine and output a metric by combining, according to predefined calibration data the provided signals.

Abstract: Apparatus, systems and methods are provided for analyzing relative compliance in the peripheral vasculature. Such apparatus, systems and methods generally involve generating a plethysmograph (PG) signal, generating one or more pressure waveforms and comparing the pressure waveform(s) relative to the PG signal to determine compliance indexes associated particular regions of the vasculature. A relative compliance ratio may also be determined by comparing arterial and venous relative compliance indexes. Apparatus, systems and methods are also provided for analyzing a PG waveform. Such apparatus, systems and methods generally involve generating a plethysmograph (PG) signal and comparing amplitude modulation of the PG signal relative to baseline modulation of the PG signal to estimate a relationship between left ventricular end diastolic pressure and stroke volume.

Abstract: An implantable medical device including a radially-expandable body and an attached detection device. The detection device includes a sensor positioned on a surface of the radially-expandable body and configured to detect endothelialization of the surface. The detection device also includes a transmitter and a receiver. Systems incorporating the implantable medical device and methods of using the device are also disclosed.

Abstract: A biometric measurement apparatus has a measurement unit for measuring bioelectric impedance of different parts of a body and hematocrit. The measurement unit has impedance calculators (IPG1, IPG2) for measuring the impedance of tissues and blood of a living body with a first frequency to output as a first impedance (Z1), and for measuring the impedance of the tissues and blood of the living body with a second frequency to output as a second impedance (Z2), and has pulse wave analyzing units (MS1 and MS2) for analyzing differences of the first impedance between a first time and a second time and difference (?ZH) of the second impedance between the first time and the second time, and a hematocrit calculator (245) for calculating hematocrit based on the difference (?ZL) of the first impedance and the difference (?ZH) of the second impedance.

Abstract: A physiologic parameter monitor includes a parameter value determiner that determines a parameter value indicative of a response of a human or animal subject to fluid intake during fluid therapy. The parameter value determiner determines the parameter value based on a signal indicative of a non-invasively obtained state of the subject. The physiologic parameter monitor also includes a display that displays the parameter value in a human readable format.

Abstract: A method of calculating blood flow in an organ of a subject using output radiofrequency signals transmitted to the organ and input radiofrequency signals received from the organ, the method comprises determining a phase shift of the input radiofrequency signals relative to the output radiofrequency signals and using the phase shift to calculate the blood flow in the organ.

Abstract: A system and method for assessing a degree of coupling between an electrode and tissue in a body is provided. Values for first and second components of a complex impedance (e.g., resistance and reactance or impedance magnitude and phase angle) between the electrode and the tissue are obtained. From these values, a coupling index is calculated that is indicative of a degree of coupling between the electrode and the tissue. The coupling index may be displayed to a clinician in a variety of ways to indicate the degree of coupling to the clinician. The system and method find particular application in ablation of tissue by permitting a clinician to create lesions in the tissue more effectively and safely.

Abstract: A method of estimating at least one intracranial hemodynamic parameter in a subject, the method comprising: a) obtaining data of changes in electrical impedance across the subject's head as a function of time; b) analyzing the data; and c) estimating one or more of intracranial pressure, cerebral blood volume, and a factor related to at least one of cerebral perfusion pressure and a mean transit time through cerebral capillaries.

Abstract: An analyte measuring system has an implantable medical device having a signal source arranged for generating a current signal and electrodes for applying the current signal to a surrounding tissue in a subject body. The device measures a resulting voltage signal with the electrodes and calculates an impedance signal therefrom. The system comprises a signal processor arranged for generating an estimate of a concentration of an analyte in the tissue based on a spectrum analysis of the determined impedance signal.

Abstract: A method of calculating blood flow in an organ of a subject using output radiofrequency signals transmitted to the organ and input radiofrequency signals received from the organ, the method comprises determining a phase shift of the input radiofrequency signals relative to the output radiofrequency signals and using the phase shift to calculate the blood flow in the organ.

Abstract: Devices and methods for monitoring intracranial hemodynamic parameters, such as intracranial pressure, cerebral blood volume, cerebral blood flow, and cerebral perfusion pressure are disclosed. In one aspect, the devices and methods may involve receiving at least one impedance plethysmography signal. Waveforms may be extracted from the impedance plethysmography signals and used for estimating the intracranial hemodynamic parameters. Various characteristics may be determined from the waveforms to aid in the estimation of intracranial hemodynamic parameters.

Abstract: A method for producing a computationally efficient system that reduces the number of iterations required to generate a conductivity image pattern of a subsurface object, and its attendant conductivity distribution, through a solution to the system of field equations that simultaneously satisfies all of the boundary conditions and conserves internal current flux densities.

Abstract: An apparatus comprises a sheath for introducing a catheter into a blood vessel, at least one electrode provided on the sheath, at least one other electrode; and a measuring device to which at least one pair of electrodes are coupled. The measuring device measures the impedance or conduction velocity between the first electrode on the sheath and the second electrode.

Abstract: Disclosed are a fetus electrocardiogram signal measuring method and its device that are capable of measuring the electrocardiogram signals of a fetus even during fetus movements and even at a gestational age during which the measurement current is weak, without the need for reattaching the electrodes and providing any shield room, even if the mother is a hospitalized or ambulant pregnant woman. The fetus electrocardiogram signal measuring device includes (1) high input impedance electrodes, (2) region-variable ground electrodes, and (3) a differential amplifier circuit and an optimization computing section.

Abstract: A patient treatment unit for analyzing and treating abnormality of human or animal tissues, includes a display; a pulse generator circuit that outputs a sequence of electrical pulses at a pulse frequency, the electrical pulses having a pulse width, the pulse generator controlling the pulse frequency and the pulse width of the electrical pulses; a pair of probes for contacting a body of a patient and electrically coupled to the pulse generator; and a voltage and current sensing circuit that senses a voltage or a current via the probes when contacting the body of the patient.

Abstract: The present invention relates to a device and a method for monitoring an access to a patient, in particular a vascular access in extracorporeal blood treatment, in which a patient's blood is withdrawn from the patient via an arterial conduit and is returned to the patient via a venous conduit. In the device according to the present invention and in the method according to the present invention, an alternating voltage signal, relative to a common ground potential, is coupled in and out of the arterial and venous conduits, and the blood flowing through the arterial and venous conduits is at ground potential. In this way, disturbances, which can be attributed particularly to movements of the conduits, are reduced.

Abstract: A biosignal measurement apparatus including: a bracelet membrane to wear around a user's wrist; a fixing supporter to install in a first side portion of the bracelet membrane and to support a first side portion of the wrist; a moving supporter to install in a second side portion of the bracelet membrane, to move towards the fixing supporter, and closely to attach to a second side portion of the wrist; and an information control unit to calculate a distance between the first side portion of the wrist and the second side portion of the wrist by detecting a movement distance of the moving supporter, and to calculate a displacement of the radial artery of the wrist by using a predetermined constant and the calculated distance between the first side portion of the wrist and the second side portion of the wrist.

Abstract: An injection system for transferring a volume of fluid from a syringe into a patient comprises a syringe assembly having a syringe adapter configured to securely receive a pre-filled syringe and a plunger assembly configured to be selectively moved relative to the syringe adapter. The injection system further comprises a fluid delivery module comprising at least one motor to move an actuator in at least one direction. In some embodiments, the injection system additionally comprises a motion transfer cable. In one embodiment, one end of the motion transfer cable is mechanically coupled to the actuator of the fluid delivery module, and the other end is mechanically coupled to the plunger assembly of the syringe assembly. In some embodiments, movement of the actuator by the motor is transferred through the motion transfer cable to the plunger assembly, resulting in the plunger assembly moving a desired distance relative to the pre-filled syringe.

Abstract: Techniques are provided for use by a pacemaker or other implantable medical device for detecting and tracking trends in cardiopulmonary fluid transfer rates—such as heart-to-lung fluid perfusion rates and lung-to-lymphatic system fluid excretion rates—and for detecting heart failure, dyspnea or other cardiopulmonary conditions. In one example, the device periodically measures transthoracic admittance values. A first exponential time-constant (k1) is determined using curve-fitting from admittance values obtained while the patient is in a sleep posture. Time-constant k1 is representative of the fluid perfusion rate. A second exponential time-constant (k2) is determined based on admittance values obtained while the patient is standing/walking/sitting. The second exponential time-constant (k2) is representative of the fluid excretion rate from the lungs.

Abstract: A method and system are provided for determining a condition of a selected region of epithelial tissue. At least two current-passing electrodes are located in contact with a first surface of the selected region of the tissue. A plurality of measuring electrodes are located in contact with the first surface of the selected region of tissue as well. Electropotential and impedance are measured at one or more locations. An agent may be introduced into the region of tissue to enhance electrophysiological characteristics. The condition of the tissue is determined based on the electropotential and impedance profile at different depths of the epithelium, tissue, or organ, together with an estimate of the functional changes in the epithelium due to altered ion transport and electrophysiological properties of the tissue.

Abstract: An apparatus comprises a sheathe for introducing a catheter into a blood vessel, a first electrode provided on the sheathe, a second electrode; and a measuring device to which the first and second electrodes are coupled. The measuring device measures the impedance or conduction velocity between the first electrode on the sheathe and the second electrode.

Abstract: 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.

Abstract: An injection catheter for infusing therapeutic and diagnostic agents into the heart comprises a catheter body and a tip section mounted at the distal end of the catheter body. A needle control handle is provided at the proximal end of the catheter body. An injection needle extends through the tip section, catheter body, and needle control handle. The injection needle is longitudinally slidable within the tip section so that its distal end can extend beyond the distal end of the tip section upon suitable manipulation of the needle control handle. The catheter further comprises an electrode lead wire having a first end electrically connected to the injection needle and a second end electrically connected to a suitable monitoring apparatus or to a source of ablation energy. The injection needle can thus be used for mapping or ablation in addition to introducing therapeutic and diagnostic agents into the heart.

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: Devices, and methods for receiving and comparing bioimpedance signals are disclosed. In one aspect, the devices and methods may include receiving bioimpedance signals indicative of hemodynamic characteristics within a subject's brain. Bioimpedance signals may be compared, and the comparison used to provide information for diagnosing changes in arterial occlusion. Bioimpedance signals may be associated with left and right sides of a subject's brain. Signature features within the bioimpedance signals may be detected and used to determine differences in the bioimpedance signals.

Abstract: Devices, and methods for synchronizing cerebro-hemodynamic signals are disclosed. In one aspect, the devices and methods may include synchronizing first and second signals indicative of hemodynamic characteristics within a subject's brain. Differences may be determined between the synchronized signals and used to provide information for diagnosing changes in arterial occlusion. Differences between the synchronized signals may include differences, such as timing delays, between signature features of the synchronized signals. The first and second signals may be indicative of hemodynamic characteristics in first and second hemisphere's of a subject's brain. The first and second signals may be bioimpedance signals.

Abstract: A system for presenting information representative of patient electrophysiological activity, such as complex fractionated electrogram information, includes at least one electrode to measure electrogram information from the heart surface, at least one processor coupled to the at least one electrode to receive the electrogram information and measure a location of the at least one electrode within the heart, and a presentation device to present the electrogram information as associated with the location at which it was measured on a model of the patient's heart. A memory may also be provided in which to store the associated electrogram information and measured location. Data may be analyzed using both time-domain and frequency-domain information to create a three-dimensional map. The map displays the data as colors, shades of color, and/or grayscales, and may further utilize contour lines, such as isochrones, to present the information.

Abstract: A method of estimating at least one intracranial hemodynamic parameter in a subject, the method comprising: a) obtaining data of changes in electrical impedance across the subject's head as a function of time; b) analyzing the data; and c) estimating one or more of intracranial pressure, cerebral blood volume, and a factor related to at least one of cerebral perfusion pressure and a mean transit time through cerebral capillaries.

Abstract: Various techniques are provided for calibrating and estimating left atrial pressure (LAP) using an implantable medical device, based on impedance, admittance or conductance parameters measured within a patient. In one example, default conversion factors are exploited for converting the measured parameters to estimates of LAP. The default conversion factors are derived from populations of patients. In another example, a correlation between individual conversion factors is exploited to allow for more efficient calibration. In yet another example, differences in thoracic fluid states are exploited during calibration. In still yet another example, a multiple stage calibration procedure is described, wherein both invasive and noninvasive calibration techniques are exploited. In a still further example, a therapy control procedure is provided, which exploits day time and night time impedance/admittance measurements.

Abstract: A method of estimating cerebral blood flow includes obtaining a measure of time-varying blood volume in the head, using an impedance plethysmography (102 and 104), obtaining a measure of time-varying blood volume in the scalp, and using the time-varying blood volume in the head and scalp to estimate cerebral blood flow.

Abstract: Embodiments of the present invention provide blood flow sensors that can be used for measurement of various physiological parameters under a wide array of conditions. In some embodiments, the blood flow sensor can be implanted into a blood vessel and left in place indefinitely and will unobtrusively measure and record data as the patient engages in regular daily activities. The data can later be read out by a clinician using a suitable interface. In other embodiments, the data is collected and analyzed within a data collection device implanted in or attached to the patient's body, and the collection device can report to the patient on an ongoing basis or in the form of alerts issued when conditions requiring medical intervention are detected.

Abstract: A method for determining an arteriovascular condition of a subject having an arterial blood flow is shown. The method involves determining a temporal progression of an instantaneous blood flow condition of the arterial blood flow as well as deriving a slew rate of the temporal progression during an increase of the temporal progression. In addition, an arteriovascular condition indicator device is shown, which comprises: an input for receiving an input signal representing an instantaneous arterial blood flow condition of a subject and a slew rate monitor connected to the input. A corresponding control device for providing an activation signal is also shown. The control device comprises a maximum detector connected to the slew rate monitor. A method for stimulation of arteriogenesis is also shown, wherein a temporal progression of an instantaneous blood flow condition is monitored, a slew rate of the temporal progression is derived, and the maximum of the slew rate is determined.

Abstract: An electrode assembly is provided. The electrode assembly is arranged for receiving a connector. The electrode assembly includes a first electrode, a second electrode, and a bridge member extending between the first and second electrodes. The bridge member includes a first conductive trace extending from the first electrode, and a second conductive trace extending from the second electrode.

Abstract: A method to measure effective cerebral outflow pressure or intracranial pressure is disclosed. The craniospinal venous system has multiple anastomoses between the jugular veins and vertebral venous plexus. Jugular veins collapse with cervical compression or head elevation, when extrinsic pressure exceeds venous pressure. The vertebral venous plexus is exposed to intracranial pressure and collapses when intracranial pressure exceeds venous pressure. Vertebral venous plexus is not compressed with head elevation or cervical compression, because enclosure in the spinal canal protects veins from the direct effects of atmospheric pressure and cervical compression. Using cervical compression and/or head elevation blood outflow is redistributed between jugular veins and vertebral venous plexus, while the degree of cervical compression or head elevation indicates effective cerebral outflow pressure or ICP.

Abstract: A method of evaluating patients suspected of suffering from an acute stroke, the method comprising: a) obtaining signals of impedance plethysmography (IPG), photoplethysmography (PPG) or both, in the patient; b) processing the one or more signals to obtain one or more measures of cerebral hemodynamics of the patient; and c) applying a rule to match said measures to a disease indication or choice of therapy or both, for the patient.

Abstract: Apparatuses and methods are provided for determining electrode impedances of a bioelectric signal-monitoring/recording system that includes an amplifier, and electrodes connected between a subject and the amplifier. An example apparatus includes: a voltage source outputting a voltage signal; a switching arrangement including an input electrically connected with the voltage source for receiving the voltage signal, an output electrically connected with the amplifier and the electrodes, and switches between the input and the output; and a controller in communication with the switches for opening and closing the switches to establish signal paths between the voltage source and the output, the controller calculating the electrode impedances relative to voltage outputs of the amplifier for each signal path.

Abstract: An electrophysiology apparatus is used to measure electrical activity occurring in a heart of a patient and to visualize the electrical activity and/or information related to the electrical activity. A three-dimensional map of the electrical activity and/or the information related to the electrical activity is created.

Abstract: Techniques are provided for monitoring thoracic fluid levels based on thoracic impedance (ZT) and cardiogenic impedance (ZC). In one example, the implantable device tracks the maximum time rate of change in cardiogenic impedance (i.e. max(dZC/dt)) to detect trends toward hypervolemic or hypovolemic states within the patient based on changes in heart contractility. The detection of these trends in combination with trends in thoracic impedance allows for a determination of whether the thoracic cavity of the patient is generally “too wet” or “too dry,” and thus allows for the titration of diuretics to avoid such extremes. In particular, a decrease in thoracic impedance (ZT) in combination with a decrease in max (dZC/dt) is indicative of the thorax being “too wet” (i.e. a fluid overload). Conversely, an increase in thoracic impedance (ZT) in combination with a decrease in max (dZC/dt) is indicative of the thorax being “too dry” (i.e. a fluid underload).

Abstract: The device for blood flow property measurement in the body and the method of its connection to the subject enables to measure electrical impedance in the main parts of body simultaneously. The impedance is spatially localized in the particular scanning channels (5) both by the placement of the current electrodes (9) of the alternating current source (2) and by setting their frequencies, and by proper spatial placement of the voltage electrodes (6). For the purpose of the whole body measurement at least three current generators (1) and twelve scanning channels (5) are used. The number of scanning channels (5) can be adjusted as necessary. By means of this device it is possible to monitor blood pulse waves or blood flow in the particular parts of human body.

Abstract: A stretchable electrode for use in physiologic measurements on a human body, such as peripheral impedance plethysmography, is disclosed. One embodiment of the stretchable electrode comprises an uninsulated stainless steel wire braid formed into a tubular conductor surrounding an elastic core and attached to an elastic substrate or base. Other embodiments of the stretchable electrode include a garter spring, a flat braided or woven conductor and an undulating wire. The electrode is placed about a limb of a human body and elastically stretched so that the conductor is in substantially continuous circumferential electrical contact with the skin of the limb. A method of attaching the stretchable electrode to the limb of a human body is also disclosed.

Abstract: A method of monitoring an acute stroke patient, comprising: a) obtaining signals of impedance plethysmography (IPG), photoplethysmography (PPG) or both, in the patient, at least once an hour, for at least six hours; b) processing the one or more signals to obtain one or more measures of cerebral hemodynamics of the patient; c) applying a rule about alerting or not alerting medical personnel based on any of values, amount of change, and direction and rate of change of the measures.