Abstract: The method is related to control a measurement of a magnetic resonance device based on electrocardiogram signals of a patient detected by at least two channels. The method comprises the steps of: supplying the electrocardiogram signals in a first processing branch to a low pass filter and a derived value sum generator; comparing the output signal with a threshold value to generate a first comparison result; feeding the electrocardiogram signals in a second processing branch to a derived value generator; comparing said signals with an upper and a lower threshold value to generate a second comparison result; repeat the above steps for the second and if necessary further channels; evaluating all first and second comparison results for all channels in a weighted logic circuit; and triggering the measurement as a function of the result of the weighted logic circuit.

Abstract: Related to a method and system for automatically detecting and analyzing pediatric ECGs, the invention comprises a signal acquisition system, a lead number determination module, a QRS wave positioning module, a P and T wave positioning module, a template and waveform analysis module, an automatic comparison module and a display and print module. The invention is a computer-aided analysis to the electrocardiograms of pediatric patients under the age of 16, applicable to the electrocardiograms of children acquired by different numbers of leads, and can be more widely used in clinical application. Moreover, the invention adopts the combined single-lead and multi-lead method to position the easily interfered characteristic points of P, QRS and T waves of pediatric ECGs. Therefore, this method can avoid the errors caused by single-lead calculation, guarantee the accuracy of parameter calculation, and consequently guarantee the accuracy of final automatic analysis results.

Abstract: Systems and methods can be used to help discriminate between epileptic and non-epileptic seizures based on a relationship between the postictal heart electrical activity and the preictal heart electrical activity. Also disclosed is an approach to determine an R-R interval by using a time-invariant complex wavelet transform.

Abstract: Described herein are implantable systems and devices, and methods for use therewith, that can be used to monitor and treat heart failure (HF). Such implantable systems preferably includes a lead having at least two electrodes implantable in a patient's left ventricular (LV) chamber. A plurality of different sensing vectors are used to obtain a plurality of IEGMs each of which is indicative of an evoked response at a corresponding different region of the LV chamber. For each of the IEGMs, there is a determination of one or more evoked response metrics indicative of a localized cardiac function at the corresponding region of the LV chamber. The evoke response metrics can be, e.g., paced depolarization integral (PDI) and/or maximum upward slope of an R-wave, but are not limited thereto.

Abstract: Disclosed herein are systems and methods for automatically determining ST windows for ischemia detection. In one example, an R-wave is identified in a signal derived from an IEGM and the derivative signal data following the identified R-wave is analyzed so as to find portions of the derivative signal comprising samples having lower values than a predetermined threshold. Further, a portion of the derivative signal including samples having lower values than the threshold is determined to correspond to a ST window for that cardiac cycle if that portion fulfills predetermined requirements. A reference ST window based on a number of determined ST windows is determined. Using the reference ST window, ischemia can be detected by comparing IEGM data in the reference ST window with current IEGM data from a segment of the IEGM signal corresponding to the reference ST window.

Abstract: The invention relates to a method for determining the activity of the parasympathetic nervous system or of the sympathetic nervous system of the autonomic nervous system of a living being, in particular a human being, wherein a feature of the condition of the living being is determined, and the activity is determined from the feature of the condition. According to the invention, the activity of the parasympathetic nervous system and/or of the sympathetic nervous system is determined dependent on time. Advantageously, the feature of the condition is a series of heartbeats of the living being, and the activity is determined by analyzing the time intervals between the heartbeats. For this purpose, the heart rate of the living being is preferably measured, and the heartbeat is determined using first positive deflections of a ventricular stimulus (R deflection). The invention further relates to a device for carrying out the method.

Abstract: The inventive method for processing an RR series comprises a plurality of (RR) samples representing time intervals (dti) between two successive heart beats or the inverse (1/dti) of said time intervals consists in selecting (N) (RRi) samples in a main time window having a predetermined length (n), in cutting said main window into (m) subwindows (Fj), in calculating an intermediate parameter (A1) for each subwindow (Fj) on the basis of the (RRi) samples contained in the subwindow (Fj) and in calculating a final parameter as a function of the intermediate parameters (Aj). The invention is used for analysing a cardiac rhythm variability, in particular for assessing a patient's pain or stress.

Abstract: An apparatus for obtaining biometric information of driver is provided. The apparatus includes a first biometric-signal-sensing unit that is installed in the steering wheel of an automobile and senses a driver's biometric signal therefrom. Additionally, a second biometric-signal-sensing unit is installed in the driver's seat of the automobile and also simultaneously senses a driver's biometric signal. As a means of control, a controller obtains biometric information selectively using biometric signals which satisfy a preset condition in obtaining biometric information based on biometric signals sensed by the first biometric-signal-sensing unit and biometric signals sensed by the second biometric-signal-sensing unit.

Abstract: A system, a method and a recording medium for calculating a physiological index are provided. The method includes: dividing a physiological data sequence into a plurality of windows; analyzing a data segment in each window to obtain metadata that represents data characteristics of the data segment; updating the metadata including the data characteristics of all data segments in the windows up to a previous window by using the metadata corresponding to one of the windows to obtain the metadata including the data characteristics of all data segments in the windows up to a current window; and finally, calculating the physiological index by using the updated metadata.

Abstract: An ECG measuring device and a magnetic resonance scanner to permit reliable detection of R-waves in ECG signals. The R-waves are identified by: measuring at least one reference ECG signal by an ECG measuring device, identifying an R-wave in the reference ECG signal, determining from the reference ECG signal at least one reference quantity which the reference ECG signal assumes in a time interval that starts before the R-wave of the ECG signal and lasts at a maximum up to the occurrence of the R-wave, generating at least one comparison rule on the basis of the at least one reference quantity, measuring ECG signals in which R-waves are to be identified, comparing the measured ECG signals with at least one reference quantity on the basis of the at least one comparison rule and outputting a trigger signal on the basis of at least one positive result of the comparison.

Abstract: A medical device system and method for monitoring a cardiac signal in a patient senses ventricular R-waves and computes a morphology metric of an R-wave and a corresponding preceding morphology metric of a preceding R-wave. One of a difference and a ratio of the R-wave morphology metric and the preceding R-wave morphology metric is compared to an established detection threshold for discriminating premature ventricular contractions from premature atrial contractions. A cardiac signal measurement is computed from the sensed R-waves in response to detecting a premature ventricular comparison based on the comparison.

Abstract: A method and device of distinguishing premature contractions that includes a sensor sensing cardiac signals, and a processor configured to determine a plurality of intervals in response to the sensed cardiac signal, detect a premature contraction being associated with a first R-wave of the plurality of R-waves, determine whether a metric of the first R-wave is greater than a premature contraction threshold, and identify the detected premature contraction as one of a premature atrial contraction or a premature ventricular contraction in response to determining whether a metric of the first R-wave is greater than a premature contraction threshold.

Abstract: A method and device of distinguishing premature contractions that includes a sensor sensing cardiac signals, and a processor configured to determine a plurality of R-waves in response to the sensed cardiac signal, detect a premature contraction being associated with a first R-wave of the plurality of R-waves, determining a first area of the detected first R-wave, determine a second area of a second R-wave, determine a ratio of the first area and the second area, compare the ratio to a ratio threshold, and identify the detected premature contraction as one of a premature atrial contraction or a premature ventricular contraction in response to the comparing..

Abstract: A method and device of distinguishing premature contractions that includes a sensor sensing cardiac signals, and a processor configured to determine a plurality of R-waves in response to the sensed cardiac signal, detect a premature contraction being associated with a first R-wave of the plurality of R-waves, determine a first area of the detected first R-wave, compare the determined first area to an area threshold, and identifying the detected premature contraction as one of a premature atrial contraction or a premature ventricular contraction in response to the comparing.

Abstract: A system for heart performance characterization and abnormality detection includes an interface for receiving sampled data representing an electrical signal indicating electrical activity of a patient heart over multiple heart beat cycles. A signal processor automatically, decomposes the received sampled data to multiple different subcomponent signals in the time domain. The signal processor associates individual decomposed subcomponents with corresponding different cardiac rotors and determined characteristics of the subcomponents indicating relative significance of the rotors in a cardiac atrial condition. A reproduction device provides data indicating the subcomponent characteristics indicating relative significance of the rotors in a cardiac atrial condition.

Abstract: Techniques for detecting tachyarrhythmia and also for preventing T-wave oversensing use signals filtered by a narrowband bradycardia filter in combination with signals filtered by a narrowband tachycardia filter. A separate wideband filter may also be used.

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: A system, method and memory medium for operating on an electrocardiogram (ECG) signal. A multiscale short-time Fourier transform (STFT) is performed on a set of ECG samples {s(n)} to obtain a transform array. For each sufficiently energetic peak in the transform array, a refined window width value and a refined window displacement value is generated by: computing an inner product between the set of samples and each of a plurality of functions, where the plurality of functions are sufficiently close to a coarse approximation function given by the peak location; and solving a linear system Av=c for the unknown vector v, where the vector c is determined by the inner products, where the matrix A is determined by the center times of the plurality of functions. After appropriate selection, the refined window width and refined window displacement may be used to represent ECG waveform features.

Abstract: The present invention provides methods and apparatus for generating a trigger from the R wave of an electrocardiogram (ECG) waveform using a threshold that adapts to the slope of the R wave while still within the leading edge of the R wave.

Abstract: A pulse monitoring and warning method and system comprising a sensor disposable over an individual's heart and configured to sense a heart rate, the sensor configured to transmit a wireless signal; and a monitor configured to continuously receive a wireless signal from the sensor, the monitor configured to process the signal and produce an alert indication responsive to the heart rate falling below a predetermined level. The system and method employ a QRS detection algorithm, which includes several mechanisms for minimizing the impact of amplitude fluctuation, EMG interference and P/T segment interference. These mechanisms include a variable QRS detection threshold algorithm, a variable QRS search window algorithm, a QRS segment slope/width detector algorithm, and a QRS reacquisition procedure.

Abstract: In a pulse wave analyzer, an ECG signal and a pulse wave signal are detected from an object to be analyzed. A plurality of feature points are extracting from the acquired ECG signal, the feature points appearing in a waveform of the ECG signal. The acquired pulse wave signal is segmented into a plurality of pulse wave signal pieces based on times at which the feature points appear. Each of the pulse wave signal pieces is segmented every heart beat. A reference pulse wave is calculated based on the plurality of pulse wave signal pieces, by multiplying the pulse wave signal pieces by coefficients and averaging the pulse wave signal pieces multiplied by the coefficients. The reference pulse wave is used to estimate the blood pressure of the object.

Abstract: Implementations and techniques for detecting biological information of a subject based on one of a rectangular wave to rectangular wave (RR) interval in an electrocardiogram and/or a change in impedance of a human body when alternating current modulated by a code sequence having an autocorrelation property is applied to the human body are generally disclosed.

Abstract: A system and method for classifying cardiac complexes sensed during a tachycardia episode. A first cardiac signal and a second cardiac signal are sensed, where the first cardiac signal has a voltage. A first cardiac complex and a second cardiac complex of a cardiac cycle are detected in the first and second cardiac signal, respectively. A predetermined alignment feature is identified in the second cardiac complex. A datum is defined, or positioned, at a specified interval from the predetermined alignment feature of the second cardiac complex. Voltage values are then measured from the first cardiac complex at each of two or more measurement intervals from the datum. The voltage values are then compared voltage values measured from NSR cardiac complexes to classify the first cardiac complex is either a ventricular tachycardia complex or a supraventricular tachycardiac complex.

Abstract: A method for identifying R waves in an ECG signal is proposed. An ECG measuring instrument measures ECG signals of a patient in which R waves are to be detected. The measured ECG signals are compared with respective reference quantities based on at least two comparison rules. The second comparison rule is dependent on a result of a first comparison conducted according to a first comparison rule. A signal that an R wave has been detected is issued if the first and the second comparison rules are fulfilled. Making the second comparison rule dependent on the result of the first comparison rule enables an adept response to changes of measurement conditions. These changes can be taken into account in further comparisons. Therefore the detection of R waves in an ECG signal can be optimized, leading to an improvement in the image quality in ECG-triggered MR examinations.

Abstract: A method for generating a trigger signal for a magnetic resonance measurement by an R wave of an EKG signal is proposed. The EKG signal is captured by an algorithm manager. The algorithm manager includes at least a first trigger instance having a trigger algorithm. EKG signals from at least two different EKG channels are processed by the trigger algorithm. The algorithm manager includes at least a further trigger instance for capturing the EKG signal. The further trigger instance has at least one further trigger algorithm for processing EKG signals from at least two different EKG channels. The trigger signal is generated by selecting a trigger instance from the different trigger instances.

Abstract: A method for identifying a characteristic profile of an R-wave in an EKG signal is proposed. A temporal sequence of measurement values is recorded and stored with associated time value. A number of values for identified temporal derivative and their respective time values is identified in the stored measurement values. One of the values for identified temporal derivative is selected as an exemplary value. The selection includes at least one plausibility test. A sub-sequence of the stored measurement values is selected as a characteristic profile as a function of the time value associated with the exemplary value. The combination of identifying possible values by their derivative with a plausibility test makes the method particularly robust.

Abstract: Disclosed embodiments include a method for assessing fluid responsiveness implemented in a medical apparatus, a medical system, or a digital computer with one or more processors comprising: (a) measuring an electrocardiogram signal, and (b) computing a dynamic index predictive of fluid responsiveness from said electrocardiogram by calculating the R-wave amplitude variability over one or more respiratory cycles. According to one particular embodiment, the ECG changes in R-wave amplitude are calculated from the DII lead to generate a dynamic index to guide fluid therapy.

Abstract: Methods and systems for detecting capture using pacing artifact cancellation are described. One or more pacing artifact templates are provided and a cardiac signal is sensed in a cardiac verification window. Each of the pacing artifact templates may characterize the pacing artifact associated with a particular pacing energy level, for example. A particular pacing artifact template is canceled from the cardiac signal. Capture is determined using the pacing artifact canceled cardiac signal. Detection of fusion/pseudofusion beats may be accomplished by comparing a cardiac signal to a captured response template.

Abstract: A method and apparatus for analyzing the QT interval characteristics of ECG signal data having a succession of waveforms produced by the beating of the heart. ECG signal data is obtained from a patient. The R-R interval and the QT intervals of the waveforms of the ECG signal data are determined. Waveforms of the ECG signal data having a stable heart rate are selected for use in determining the QT interval characteristics. Preferably, the waveforms selected are those having minimum R-R interval standard deviation and minimum R-R interval dispersion. The QT correction (QTc) is computed from the ECG signal data waveforms selected in the foregoing manner or on the basis of clinician editing. The R-R intervals, the QT intervals, and QTc for the heart beats of the selected waveforms are displayed for analysis and diagnosis purposes. The invention can also be used, in an analogous manner, to obtain and display other cardiac data from the ECG waveforms.

Abstract: A method for accurate heart rate detection includes receiving a signal indicative of motion due to respiration, and using the signal indicative of motion to adjust a threshold value of a signal indicative of activity of the heart. The adjusted threshold value is used to detect an accurate heart rate of a patient. A system for accurate heart rate detection comprises a motion sensor which produces a signal indicative of motion due to respiration, and a processor which adjusts a threshold value of a signal indicative of activity of the heart according to the signal indicative of motion. The adjusted threshold value is used to detect an accurate heart rate of a patient. The motion sensor can be any device that can determine direction of motion, such as an accelerometer, a displacement sensor, a velocity sensor, or a photoplethysmography (PPG) sensor.

Abstract: A PC-based ECG software program that in real time, acquires, analyzes and displays QTV and PQ interval variability (PQV) in each of the independent channels that constitute the 12-lead conventional and/or Frank X, Y, Z lead ECG. The system also analyzes and displays the QTV and PQV from QT and PQ interval signals that are derived from multiple channels and from singular value decomposition such that the effect of noise and other artifacts on the QTV and PQV results are substantially reduced compared to existing single-channel methods. Moreover, this invention also provides certain new parameters of T-wave (and QRS and P-wave) morphology, that in initial studies have improved clinical diagnostic utility and/or reproducibility and reliability compared to known existing parameters of T-wave morphology. Finally, it also provides a method for determining the beat-to-beat variability these T, QRS and P-wave morphologic parameters.

Abstract: Disclosed is a system for the detection of cardiac events (a guardian system) that includes an implanted device called a cardiosaver, a physician's programmer and an external alarm system. The system is designed to provide early detection of cardiac events such as acute myocardial infarction or exercise induced myocardial ischemia caused by an increased heart rate or exertion. The system can also alert the patient with a less urgent alarm if a heart arrhythmia is detected. Using one or more detection algorithms, the cardiosaver can detect a change in the patient's electrogram that is indicative of a cardiac event within five minutes after it occurs and then automatically warn the patient that the event is occurring. To provide this warning, the guardian system includes an internal alarm sub-system (internal alarm means) within the cardiosaver and/or an external alarm system (external alarm means).

Abstract: An exemplary method includes detecting a QRS complex using cutaneous electrodes, during the QRS complex, detecting an R-wave of a ventricle using an intracardiac electrode, determining if the R-wave occurred during a first, predetermined percentage of the QRS complex width and, based at least in part on the determining, deciding whether a patient is likely to respond to cardiac resynchronization therapy. Such a method may set the predetermined percentage to approximately 50%. An exemplary model includes a parameter for a percentage for the timing of an EGM R-wave with respect to the total width of an ECG QRS complex. Various other exemplary methods, devices, systems, etc. are also disclosed.

Abstract: An implantable medical device monitors ST segment data collected from EGM. ST trends are established and monitored over time. The IMD is able to discern whether the data indicate supply ischemia, demand ischemia, or other physiological causes. The IMD is then able to provide appropriate information and alerts.

Abstract: Method and apparatus for sensing improvement using pressure data. The method and apparatus may be used in an implantable medical device to confirm that an EGM event signifies a true mechanical cardiac activity and not just electrical oversensing. The mechanical activity may be used to create a mechanical marker channel in the implantable medical device.

Abstract: A method and system for automatically determining ischemia detection parameters are provided. The method includes obtaining a baseline trace indicative of a cardiac behavior, determining an ischemia detection window based on at least one physiologic state indicator within the baseline trace, and automatically identifying a fiducial point based on the baseline segment trace. The baseline trace includes a baseline segment within the ischemia detection window; where the ischemia detection window and the fiducial point may constitute ischemia detection parameters.

Abstract: A system for synchronizing application of treatment signals with a cardiac rhythm is provided. The system includes a memory that receives and stores a synchronization signal indicating that a predetermined phase such as R-wave of a cardiac rhythm of a patient has started. A synchronization module analyzes whether the stored synchronization signal is erroneous and if so, prevents a medical treatment device from applying a treatment energy signal such as an IRE pulse to a patient to take into account an irregular heart beat and noise in the synchronization signal in order to maximize safety of the patient.

Abstract: A system automatically detects and measures ST deviation of a heart wave ECG signal in the presence of noise and accommodates baseline variation of the signal and other artefacts. A system identifies a particular point in an electrophysiological signal representing heart electrical activity using an interface for receiving an electrical signal waveform comprising an R-wave and including an ST segment portion associated with heart electrical activity of a patient over a heart beat cycle. A signal processor processes data representing the electrical signal waveform by identifying an S point and T point in the electrical signal waveform and determining a first candidate J point in the electrical signal waveform having substantially a maximum distance from a line between the identified S and T points, the distance being measured perpendicularly to the line.

Abstract: A Fast Fourier Transform (FFT) converts time-varying event waveforms into the frequency domain waveforms to thereby decompose the events into their spectral components, which are analyzed to distinguish R-waves from T-waves. In some embodiments, the FFT is only activated if a ventricular tachyarrhythmia is already indicated. For example, an initial ventricular rate may be derived from a ventricular IEGM based on all events detected therein. The initial ventricular rate is compared against one or more thresholds representative of ventricular tachycardia (VT) and/or ventricular fibrillation (VF) to determine if VT/VF is indicated. If so, the FFT is activated to distinguish R-waves from T-waves and, in particular, to detect and eliminate T-wave oversensing. Then, the ventricular rate is re-determined based only on the rate of true R-waves. Therapy is delivered if VT/VF is still detected.

Abstract: The present invention relates to a method for recognizing and measuring heartbeat in physical training, in which method individual heartbeats are recognized and measured from the electrical signal of the heart, the EKG signal, on the area of waist and/or on the body area below the waist by means of two or more electrodes (2, 3) integrated to an outfit (1) or to a part of an outfit, and/or by means of two or more electrodes integrated to one or several wearable sensors, and for calculating various quantities describing the function of the heart. In the method in accordance with the invention, for recognizing and measuring heartbeat, the signals received from the heart are processed and examined with two or more different ways for improving the reliability of calculation and for decreasing the impact of noises.

Abstract: Provided is an ultrasonograph that can automatically optimize the sweep rate of Doppler images and M-mode images according to the heart rate of a test subject, without the need for an operator to perform a troublesome operation. The ultrasonograph is provided with a means for sending an ultrasonic beam into body tissue, a means for receiving an ultrasonic signal that has been reflected off the body tissue and a blood flow, a means for constructing a cross-sectional image of the body tissue from the received ultrasonic signal, a means for performing phase detection on an ultrasonic Doppler blood flow signal that has been reflected off the body tissue by the blood flow, a means for calculating a frequency component of the Doppler blood flow signal on which phase detection has been performed, and a means for performing a sweeping display of the calculated frequency component as Doppler images in a time series.

Abstract: In one aspect of the invention, there is provided a method and apparatus for early detection of subacute, potentially catastrophic infectious illness in a premature newborn infant. The method comprises: (a) continuously monitoring heart rate variability in the premature newborn infant; and (b) identifying at least one characteristic abnormality in the heart rate variability that is associated with the illness. This method can be use to diagnose illnesses such as, but not limited to, sepsis, necrotizing enterocolitis, pneumonia and meningitis. In another aspect of the present invention, there is provided a method and apparatus for early detection of subacute, potentially catastrophic infectious illness in a patient.

Abstract: A method for operating a cardiac rhythm management device in which a clinical state vector is computed as a combination of a plurality of parameters related to a patient's heart failure status and compared to a previously computed clinical state vector to determine a clinical trajectory indicative of changes in the patient's heart failure status. Such detected changes in status can be used both as a clinical tool to evaluate treatment and to automatically adjust the operation of the device.

Abstract: Methods and apparatus for determining a patient specific QT-RR curve. One embodiment of a method in accordance with the technology comprises providing electrophysiological data for a specific patient. The method can further include: (a) determining QT durations and RR values for a plurality of heart beats of the specific patient from the electrophysiological data; (b) ascertaining effective RR intervals for the plurality of heart beats by weight-averaging the RR values according to the equation Effective RRi=C×Effective RRi-1+(1?C)×[RRweighted], where C is a number between 0 and 1, and where RRweighted is based on an observed RRi value and a trend predicted RR value; and (d) finding a value Cf defined by a value of C where a curve fitted to the QT durations and the ascertained effective RR intervals is within a desired standard deviation.

Abstract: A method for identifying R-waves in an ECG signal for the purpose of triggering further measurements or examinations is proposed. A reference ECG signal by an ECG measuring device is measured. An R-wave in the reference ECG signal is identified. A reference quantity is determined from the reference ECG signal. The reference ECG signal assumes in a time interval that starts before the R-wave of the ECG signal and lasts at a maximum up to the occurrence of the R-wave. A comparison rule is generated based on the reference quantity. ECG signals are measured in which R-waves are to be identified. The measured ECG signals are compared with the reference quantity based on the comparison rule. A trigger signal is outputted based on a positive result of the comparison.

Abstract: An exemplary method to reduce risk of ventricular oversensing includes sensing, in vivo, amplitude of electrical cardiac activity, comparing sensed amplitude to a low sensitivity threshold where if the comparing indicates that sensed amplitude does not meet or exceed the low sensitivity threshold then further comparing the sensed amplitude to a high sensitivity threshold and if the further comparing indicates that sensed amplitude meets or exceeds the high sensitivity threshold then determining that ventricular fibrillation may exist. Various exemplary devices, systems, methods, etc., are disclosed.

Abstract: There is provided a pulse wave data analyzing method for extracting vital information out of pulse wave data concerning a living body.

Abstract: Systems and methods for detecting and/or treating nervous system disorders, such as seizures, are disclosed. Certain embodiments of the invention relate generally to implantable medical devices (IMDs) adapted to detect and treat nervous system disorders in patients with an IMD. Certain embodiments of the invention include detection of seizures based upon comparisons of long-term and short-term representations of physiological signals. Other embodiments include prediction of seizure activity based upon analysis of physiological signal levels. An embodiment of the invention monitors the quality of physiological signals, and may be able to compensate for signals of low signal quality. A further embodiment of the invention includes detection of seizure activity following the delivery of therapy.

Abstract: A chip for sensing a physiological signal comprises: an input unit for receiving a first electrocardiogram (ECG) signal; a filter for generating a second ECG signal by filtering the first ECG signal; an amplifying unit for generating a third ECG signal by amplifying the second ECG signal; an Analog-to-Digital converting unit for converting the third ECG signal into a digital signal; an operating unit for generating a plurality of analysis data by operational analyzing the digital signal; and an output unit for outputting the plurality of analysis data. Therefore, the manufacturing cost of the chip is decreased and the chip is suitable for use in small-scale devices.

Abstract: An method for analyzing irreversible apneic coma (IAC) for determining the presence of irreversible apneic coma (IAC) by analyzing the heart rate variability of a brain traumatic patient, thereby providing a physician a reference index to determine whether brain death has occurred. This method includes, at first, recording an electrocardiogram (ECG) from a subject. Then, analyzing R-R interval in said electrocardiogram (ECG), and plotting said R-R interval into Poincaré plot, wherein the X coordinate in said Poincaré plot represents R-R interval(n), and n is a 1˜data number. Y coordinate in said Poincaré plot represents RR(n+1). And, finally, quantifying said Poincaré plot, and obtaining semi-major axis (SD1), semi-minor axis (SD2), and SD1/SD2 of said Poincaré plot, as well as Poincaré plot area.