Abstract: A device senses cardioelectrical signals using a right atrial (RA) lead, which might include far-field R-waves as well as near-field P-waves. The device concurrently senses events using a proximal electrode of an LV lead, which can sense both P-waves and R-waves as substantially near-field events. Suitable templates are then applied to the signals sensed via the proximal LV electrode to identify the origin of the signals (e.g. atrial vs. ventricular) so as to properly classify the corresponding events sensed in the RA as near-field or far-field events. In this manner, far-field oversensing is conveniently detected.

Abstract: In general, the disclosure describes techniques for storing data corresponding to sensed high-rate non-sustained episodes that occur close in time to detection of a lead integrity condition. A method comprises detecting a first high-rate non-sustained episode, activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the first episode, and storing data associated with the first episode in an episode log in response to activating the data storage operation. Another method comprises detecting a lead integrity condition, and activating a data storage operation for storing data associated with high rate non-sustained episodes in response to detecting the condition.

Abstract: A system and method provide detecting and monitoring cardiac electrophysiological changes by determining differences between a reference signal representing a heartbeat signal and an analysis signal representing another heartbeat signal. A set of signal data consisting of a number of heartbeat signals is acquired as a function of time. Individual heartbeat signals within the set of acquired signals are identified, an individual signal comprising data values representing a plurality of sample points during a single heartbeat. One of the identified individual signals or a derived signal representing an average of a subset of the identified individual signals is selected as an analysis signal. A reference signal is identified. The sample points of the reference signal are aligned with the sample points of the analysis signal. A single value representative of mutual correspondence between the sample points of the reference signal and the corresponding sample points of the analysis signal is calculated.

Abstract: An atrial fibrillation decision apparatus includes an acquisition unit that acquires a detected waveform signal indicating a detection result of an electrocardiogram or pulse wave, an RR interval calculation unit that calculates a parameter corresponding to the RR interval with respect to each frame on the basis of a spectrum of each frame obtained through frequency analysis of the detected waveform signal acquired, and an RR waveform signal that indicates a temporal change of the parameter, a power calculation unit that calculates a temporal change of power of a predetermined frequency band of the RR waveform signal, and a decision unit that decides whether the calculated power satisfies a specific condition and outputs information indicating whether atrial fibrillation is taking place, on the basis of the detection result.

Abstract: Systems and Methods for stratifying relative risks of adverse cardiac events by processing a duration of electrocardiograph recordings generally recorded by a Holter type of device. The duration of electrocardiograph recordings are processed to resolve RR interval related data, QT interval related data, and are fitted to formulas to at least partially establish fitting related measures. The fitting formulas incorporate circadian related periodic factors, and can further incorporate additional processing including utilizing Lissajous analysis techniques, among others.

Abstract: This document discusses, among other things, systems and methods to discriminate between a ventricular tachyarrhythmia (VT) and a supraventricular tachyarrhythmia (SVT), such as upon detecting sudden onset and one-to-one tachycardia. In certain examples, a detected tachyarrhythmia is analyzed to determine whether it is sudden onset and 1:1. If so, a first fast beat is identified. One or more ventricular intervals in close proximity to the first fast beat are analyzed to determine an initial classification of either VT or SVT. The initial classification is used to adjust a morphological feature correlation coefficient (FCC) threshold. A morphology analysis is performed with the adjusted FCC threshold value to yield a secondary classification.

Abstract: Detected changes in atrial activation can be used to discriminate between hemodynamically stable and hemodynamically unstable tachyarrhythmias.

Abstract: Described herein are implantable systems and devices, and methods for use therewith, that can be used to perform arrhythmia discrimination based on activation times. A plurality of different sensing vectors are used to obtain a plurality of IEGMs that collectively enable electrical activations to be detected in the left atrial (LA) chamber, the right atrial (RA) chamber, and at least one ventricular chamber of a patient's heart. For each of a plurality of cardiac cycles, there is a determination, based on the plurality of obtained IEGMs, of an LA activation time, an RA activation time, and a ventricular activation time. Arrhythmia discrimination is then performed based on the determined activation times.

Abstract: This document discusses, among other things, detection of a sudden onset of a tachyarrhythmia. A sudden onset of tachyarrhythmia is determined by monitoring changes in intrinsic ventricular rate, such as by using one or more sensing channels in the ICD. A lowest tachyarrhythmia rate threshold is accompanied by a slightly lower “hysteresis tachyarrhythmia rate threshold.” If a sudden onset of tachyarrhythmia is declared, the sudden onset status is not reset by the ventricular rate falling below the lowest tachyarrhythmia rate threshold, but is instead reset by the ventricular rate falling below the slightly lower hysteresis tachyarrhythmia rate threshold.

Abstract: Detected changes in atrial activation can be used to discriminate between hemodynamically stable and hemodynamically unstable tachyarrhythmias.

Abstract: A method, a system and an arrangement to predict at least one system event and a corresponding computer program and a corresponding machine-readable storage medium are configured so that the event is predictable because of trends in observables over a certain period before the occurrence of the events. The method, system and arrangement can be used in particular for patient-specific monitoring of patho-physiological changes but also in geophysical or abstract units such as population or economic systems in which the deviation from a defined normal condition is predicted.

Abstract: An implantable cardioverter/defibrillator (ICD) includes a tachyarrhythmia detection and classification system that classifies tachyarrhythmias based on a morphological analysis of arrhythmic waveforms and a template waveform. Correlation coefficients each computed between morphological features of an arrhythmic waveform and morphological features of the template waveform provide for the basis for classifying the tachyarrhythmia. In one embodiment, morphological features are collected from a sensed arrhythmic waveform, and temporally corresponding morphological features are extracted a stored template waveform.

Abstract: A method and a system for detection of an arrhythmia and discrimination between different types of arrhythmia to determine whether to administer an electric shock to the heart, the method comprising monitoring the electrical activity of a beating heart, selecting a number of heart beat intervals that will comprise an analysis segment; determining an instantaneous heart rate for each of the heart beat intervals with the segment; calculating the mean instantaneous heart rate for the segment; determining the variability of the instantaneous heart rates compared to a mean; using a linear combination of the mean and the non-linear value for comparison with a predetermined threshold to discriminate the type of arrhythmia to automatically decide if intervention is indicated.

Abstract: The invention relates to a method for determining a pathology in a subject, said method comprising: a) correlating N-N intervals with rate dependent fluctuations of electrocardiographic parameters derived from an electrocardiogram (ECG) of said subject or other recordings reflecting cardiac activity of said subject to derive electrocardiographic parameters correlation values, wherein said pathology is determined based on said correlation values.

Abstract: An electromedical implant, having a far-field electrocardiogram capturing unit for recording a far-field electrocardiogram signal, which is connected or can be connected to at least two electrodes for recording electric signals reflecting the curve of the far-field electrocardiogram of the right and left atria, a detection unit, which is designed to detect signal features characterizing atrial cardiac actions in an electrocardiogram signal, an averaging unit, which is connected to the recording unit and the detection unit and designed to generate an averaged P-wave signal in that the averaging unit averages a plurality of signal sections of the electrocardiogram signal associated with a particular detected atrial cardiac action, and an evaluation unit, which is connected to the averaging unit and designed to determine the duration of an averaged P-wave in the particular averaged P-wave signal.

Abstract: Techniques for determining whether one or more leads are not adequately connected to a patient, e.g., for ECG monitoring, are described. The techniques involve injection of an integrated signal (which includes a test signal) into one lead, and monitoring the driven lead and the response at the other leads, including the common mode and the difference between the other leads. These “lead-off” detection techniques may be provided by an external defibrillator that provides three-wire ECG monitoring. Techniques for determining a type of a cable coupled to a defibrillator are also described. The cable-type identification may allow a defibrillator to, for example, operate in either a three-wire ECG monitoring mode or a therapy mode, based on whether a three-wire ECG cable or a defibrillation cable is coupled to the defibrillator.

Abstract: A medical device and associated method for monitoring a patient's heart rhythm sense cardiac events and detect a sudden change in the heart rhythm in response to the sensed cardiac events. Detecting the sudden change includes determining a variability of intervals between the sensed cardiac events and switching between a low variability mode of operation and a high variability mode of operation in response to the variability of intervals. During the low variability mode, detecting the sudden change includes detecting an increase in the rate of cardiac events. During the high variability mode, detecting the sudden change includes detecting a sudden decrease in the variability of the cardiac event intervals. A concerning cardiac rhythm is detected in response to detecting the sudden change.

Abstract: The invention disclosed includes a method and apparatus for calculation of T-wave alternas in electrocardiographic (ECG) signals; said method comprises the following method steps: (a) collecting and storing an ECG signal; (b) detecting each heartbeat T-wave in the ECG signal using an automatic detection and segmentation algorithm; (c) classifying said heartbeat T-wave as an even or odd heartbeat T-wave; (d) initializing said method by taking the first even and the first odd heartbeat T-wave as their respective initial average; (e) processing all the heartbeat T-waves in the ECG signal to generate an even heartbeat T-wave weighted average and odd heartbeat T-wave weighted average; and (f) calculating TWA using a distance metric between the even heartbeat weighted average and the odd heartbeat weighted average, said distance metric including curve matching Continuous Dynamic Time Warping (CDTW).

Abstract: A CRM system enhances intracardiac electrogram-based arrhythmia detection using a wireless electrocardiogram (ECG), which is a signal sensed with implantable electrodes and approximating a surface ECG. In one embodiment, an intracardiac electrogram allows for detection of an arrhythmia, and the wireless ECG allows for classification of the detected arrhythmia by locating its origin. In another embodiment, the wireless ECG is sensed as a substitute signal for the intracardiac electrogram when the sensing of the intracardiac electrogram becomes unreliable. In another embodiment, a cardiac signal needed for a particular purpose is selected from one or more intracardiac electrograms and one or more wireless ECGs based on a desirable signal quality. In another embodiment, intracardiac electrogram-based arrhythmia detection and wireless ECG-based arrhythmia detection confirm with each other before indicating a detection of arrhythmia of a certain type.

Abstract: The invention provides a cardiac rhythm management system which includes a tachyarrhythmia detection and classification circuit programmed to detect and classify a tachyarrhythmia, a biologic therapy delivery device configured to deliver or regulate an expression cassette suitable for terminating or preventing atrial fibrillation (AF), and a control circuit coupled to the tachyarrhythmia detection and classification circuit and the biologic therapy delivery device. Also provided is an implantable medical device for use in a body having a cardiovascular system, which includes an implantable device body including at least a cardiovascular portion configured to be in the cardiovascular system, and an expression cassette incorporated into the cardiovascular portion of the implantable device body, the expression cassette selected to express a gene product that terminates or prevents AF. Further provided are methods which employ particular expression cassettes to prevent, inhibit or treat AF.

Abstract: Techniques are described for detecting a condition of a patient using a probability-correlation based model that integrates a plurality of parameters associated with the condition. A medical device that operates in accordance with the techniques obtains a plurality of parameters associated with the condition of the patient. The medical device obtains probabilities that the condition of the patient exists based on each single parameter separately and correlations between each of the parameters and the other ones of the parameters. After obtaining the probabilities and correlations associated with each of the parameters, the medical device determines whether the condition of the patient exists based on the determined probabilities and correlations. Such techniques may be particularly effective for use in distinguishing whether a rhythm of a patient is treatable, e.g., VT or VF, or non-treatable, e.g., SVT.

Abstract: An apparatus comprises an implantable ventricular depolarization sensing circuit configured to provide a sensed ventricular depolarization signal, a timer circuit configured to provide a ventricular time interval between ventricular depolarizations, and a controller circuit communicatively coupled to the ventricular depolarization sensing circuit and the timer circuit. The controller circuit includes a ventricular tachycardia (VT) detection circuit configured to declare an episode of VT when a number of accelerated beats are detected, calculate a hysteresis VT detection threshold interval, and deem whether the episode of VT persists using the hysteresis VT detection threshold interval.

Abstract: A medical device and associated method for discriminating cardiac events sense cardiac signals that includes determining whether a first match score is within one of a first match zone corresponding to a first cardiac event, and a second match zone corresponding to the first cardiac event, and determining whether a second match score is within one of the first match zone, the second match zone, and a third match zone corresponding to a second cardiac event different from the first cardiac event. One of increasing and decreasing an event counter is performed in response to both the determination of whether the first match score is within one of the first match zone and the second match zone and the determination of whether the second match score is within one of the first match zone, the second match zone, and the third match zone.

Abstract: An apparatus comprises a first implantable sensor produces a first electrical sensor signal representative of cardiac depolarization events of a heart of a subject, a second implantable sensor that produces a second electrical sensor signal representative of hemodynamic function of the heart, a signal analyzer circuit, and an arrhythmia discrimination circuit. The signal analyzer circuit detects an arrhythmic event from the first sensor signal and calculates hemodynamic stability in response to the arrhythmic event detection using the second sensor signal.

Abstract: This disclosure describes various techniques for discriminating supraventricular tachycardia (SVT) from ventricular tachycardia (VT). As one example, a method includes detecting a tachycardia rhythm, identifying a rate of change in heart rate corresponding to the tachycardia rhythm, identifying a rate of change in heart rate variability corresponding to the tachycardia rhythm, and classifying the tachycardia rhythm as at least one of supraventricular tachycardia or ventricular tachycardia based on the rate of change in heart rate and rate of change in heart rate variability.

Abstract: A medical device and associated method for discriminating cardiac events includes determining whether a first match score is within a first match zone having a first correlation with a non-treatable cardiac event, a second match zone having a second correlation with the non-treatable cardiac event less than the first correlation, a third match zone having a first correlation with a treatable cardiac event, and a fourth match zone having a second correlation with the treatable cardiac event greater than the first correlation with the treatable cardiac event. In response to the first match score being within one of the first and second match zones, a determination is made whether consecutive match scores are within the first match zone and whether a break in the treatable cardiac event has occurred. Cardiac evidence is accumulated in response to determining whether a break has occurred and utilized to discriminate cardiac events.

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: Methods, systems, and devices for signal analysis in an implanted cardiac monitoring and treatment device such as an implantable cardioverter defibrillator. In illustrative examples, sensed data including detected events is analyzed to identify likely overdetection of cardiac events. In some illustrative examples, when overdetection is identified, data may be modified to correct for overdetection, to reduce the impact of overdetection, or to ignore overdetected data.

Abstract: An implantable medical device controls an anti-tachyarrhythmia therapy by detecting a tachyarrhythmia episode from a cardiac signal and analyzing the detected tachyarrhythmia episode in a tachyarrhythmia detection and analysis process to determine whether the anti-tachyarrhythmia therapy needs to be delivered. The tachyarrhythmia detection and classification process includes detection of inhibitory events each indicating that the tachyarrhythmia episode is of a type not to be treated by the anti-tachyarrhythmia therapy or that the tachyarrhythmia episode is not sustaining. The detection of each of the inhibitory events causes the tachyarrhythmia detection and classification process to be restarted or extended, or the delivery of the anti-tachyarrhythmia therapy to be withheld.

Abstract: Post-exercise arrhythmias are detected by an implantable medical device. In some aspects, post-exercise arrhythmia may be prognostic of a worsening cardiovascular condition. Thus, the detection of post-exercise arrhythmia may be used as an indicator for adjusting the therapy prescribed for a patient. In some aspects post-exercise arrhythmia are detected if a patient is exercising at a level that equals or exceeds a threshold exercise level. In some aspects, therapy for a patient is modified if the detected post-exercise arrhythmia exceeds a threshold arrhythmia level. In some aspects therapy for a patient is modified if ischemia is detected in conjunction with post-exercise arrhythmia.

Abstract: A system includes an implantable medical device. The implantable medical device includes a control circuit and a motion sensing device. The motion sensing device is coupled to the control circuit, and the motion sensing device is configured to transmit signals to the control circuit. The control circuit is configured to identify one or more steps of a patient using the motion sensing device signal.

Abstract: The present invention provides a method and apparatus for detecting and monitoring obstructive sleep apnea. The apparatus measures sinus tachycardia and a change in the atrial-ventricular conduction, and includes a controller for receiving the measurement of the sinus tachycardia and the change in the atrial-ventricular conduction to detect obstructive sleep apnea based upon the sinus tachycardia and the change in the atrial-ventricular conduction.

Abstract: An implantable medical device system and associated method monitor changes in transimpedance in a body tissue due to changes in cardiac pulsatility. A first dipole is used to deliver a non-stimulating electrical current. The first dipole includes a first electrode and a second electrode adapted to be deployed along a first body location. A second dipole is used to measure a voltage resulting from the non-stimulating electrical current being conducted through a portion of a patient's body. The second dipole includes a third electrode and a fourth electrode different than the first electrode and the second electrode and adapted to be deployed along a second body location spaced apart from the first body location.

Abstract: An apparatus comprises an implantable impedance sensing circuit configured to sense an atrial impedance signal when coupled to a plurality of implantable electrodes, and an impedance signal analyzer circuit configured to detect a sudden change in a characteristic of the sensed atrial impedance signal that indicates atrial tachyarrhythmia. The impedance signal analyzer circuit classifies the atrial tachyarrhythmia indication as ST when the detected sudden change satisfies an ST threshold value of the characteristic, classifies the atrial tachyarrhythmia indication as AT when the detected sudden change satisfies an AT threshold value of the characteristic that is different from the ST threshold value, classifies the atrial tachyarrhythmia indication as AF when the detected sudden change satisfies an AF threshold value of the characteristic that is different from the ST and AT amplitude threshold values, and provides a classification of the tachyarrhythmia to a user or process.

Abstract: A method for calculating a variability value that is indicative of AF by obtaining a signal sequence of a plurality of RR intervals by monitoring electrical activity of a patient's heart. Each RR interval is converted into an instantaneous heart rate value and sorted into ascending order. The difference between each successive heart rate is calculated, discarding the two largest differences. The variability value is calculated by adding the retained differences.

Abstract: Systems and methods that enable physiological monitoring with a mobile communication device and that allow detection of motion artifacts so that the results reported are of acceptable quality are disclosed.

Abstract: Systems and methods are described for classifying a cardiac rhythm. A cardiac rhythm is classified using a classification process that includes a plurality of cardiac rhythm discriminators. Each rhythm discriminator provides an independent classification of the cardiac rhythm. The classification process is modified if the modification is likely to produce enhanced classification results. The rhythm is reclassified using the modified classification process.

Abstract: A non-invasive system and method of diagnosing and predicting cardiac disease in a patient's heart is disclosed that comprises a microprocessor which contains a signal processor and a pattern recognition processor; detect the electrophysiological signals of the heart whereby the signals are processed to create a pattern that represents the patient's heart. The pattern may be further processed by repeatedly comparing it to patterns stored within the pattern recognition processor whereby certain coronary diseases such as myocardial ischemia in the patient's heart may be diagnosed. During each heartbeat, at least a million different electrical signals are collected and the results of test are displayed on a screen. The results may include the diagnosis, computer generated image of the patient's heart identifying areas of any cardiac disease that has been detected and/or a two dimensional non-linear waveform representing the electrophysiological signals of the patient's heart.

Abstract: An implantable medical device is connectable to at least three electrodes, and includes an immittance measurer that performs immittance measurements within the heart of a patient using at least three electrodes coupled to the device, with at least one of the electrodes is arranged in an atrium of the patient's heart. The medical device further includes an immittance converter that converts the immittance measurement values into individual near-field immittance values of the at least one electrode arranged in an atrium, an atrial dilatation detector that detects atrial dilatation based upon the individual near-field immittance values, and that determines atrial dilatation values in dependence thereon, and an atrial fibrillation risk determiner that determines an atrial fibrillation risk index based upon the atrial dilatation values.

Abstract: Techniques for discrimination of heart rhythms in cardiac rhythm management devices include determining a current covariance matrix of multiple electrograms measuring each current heart beat, determining a distance measure between the current covariance matrix and a predetermined covariance matrix of the multiple electrograms measuring at least one different heart beat; and determining whether the heart beat represents ventricular tachycardia based on the distance measure.

Abstract: Techniques for storing electrograms (EGMS) that are associated with sensed episodes or events that may be non-physiological and, instead, associated with a sensing integrity condition are described. In some examples, a device or system identifies suspected non-physiological NSTs, and stores an EGM for the suspected non-physiological NSTs within an episode log. In some examples, a device or system determines whether to store an EGM for a suspected non-physiological episode or event based on whether an impedance integrity criterion has been satisfied. For example, a device or system may store an EGM for a detected short interval if the impedance integrity criterion has been met. In some examples, a device or system determines whether to buffer EGM data based on whether an impedance integrity criterion or other sensing integrity criterion has been met.

Abstract: The invention provides a system and method for measuring vital signs (e.g. SYS, DIA, SpO2, heart rate, and respiratory rate) and motion (e.g. activity level, posture, degree of motion, and arm height) from a patient. The system features: (i) first and second sensors configured to independently generate time-dependent waveforms indicative of one or more contractile properties of the patient's heart; and (ii) at least three motion-detecting sensors positioned on the forearm, upper arm, and a body location other than the forearm or upper arm of the patient. Each motion-detecting sensor generates at least one time-dependent motion waveform indicative of motion of the location on the patient's body to which it is affixed.

Abstract: An active medical device able to discriminate between tachycardias of ventricular origin and of supra-ventricular origin. Two distinct temporal components (UnipV, BipV) are obtained corresponding to two EGM signals of ventricular electrograms. The diagnosis operates in at least two-dimensional space to determine, from the variations of one temporal component as a function of the other temporal component, a 2D characteristic representative of a heart beat and, this, for a reference beat collected in Sinus Rhythm (SR) in the absence of tachycardia episodes, and for a heart beat in Tachycardia. The discrimination of the tachycardia type, VT or SVT, is then realized by a classifier operating a comparison of the two current and reference 2D characteristics.

Abstract: Method for detecting cardiac events, e.g., Atrial Fibrillation (AF) or termination of AF. Based on analysis of the instability observed in heart rate, caused by irregular conduction from the atrium during AF. Change in heart interval is monitored on beat-to-beat basis to recognize instability that indicates presence of AF or Atrial Flutter. A packet of a number of consecutive intervals is evaluated, whether the length of an interval is stable compared with the length of the preceding interval, or whether the length of the subsequent interval has changed. After detection of an instability, instability counter is incremented. The result of the stability test for a packet of intervals is represented by the value of the instability counter. Depending upon whether or not an AF already declared, (indicated by AF status flag), different “X-out-of-Y” criterion are applied. AF status flag set/cleared when declaring AF/termination of AF.

Abstract: A system and method for use in a medical device for discriminating cardiac events establishes population-based thresholds corresponding to cardiac signal morphology metrics for discriminating between a first cardiac event and a second cardiac event. A population-based threshold criterion for discriminating cardiac events is established. The population-based threshold criterion is applied to a cardiac signal segment and the segment is classified if the criterion is satisfied. A patient-specific threshold is established in response to the sensed cardiac signal segment not being classified after applying the population-based threshold criterion. The sensed signal segment is classified in response to the patient-specific threshold comparison.

Abstract: A method of automatically determining which type of treatment is most appropriate for (or the physiological state of) a patient. The method comprises transforming one or more time domain measurements from the patient into frequency domain data representative of the frequency content of the time domain measurements; processing the frequency domain data to form a plurality of spectral bands, the content of a spectral band representing the frequency content of the measurements within a frequency band; forming a weighted sum of the content of the spectral bands, with different weighting coefficients applied to at least some of the spectral bands; determining the type of treatment (or physiological state) based on the weighted sum.

Abstract: A wireless system for monitoring a patient's brain tissue including (1) a plurality of electrodes abutting brain tissue, (2) main circuitry outside the patient's body to transmit power at radio frequencies and send/receive data using infrared energy, and (3) subcutaneously-implanted remote circuitry connected to the electrodes and configured to (a) receive transmitted RF power, (b) capture and digitize EEG signals from the electrodes, and (c) send/receive data to/from the main circuitry using IR energy, including sending digitized EEG signals from each electrode to capture the full bandwidth of each EEG signal. The system preferably includes circuitry to measure the electrical impedance of each electrode for real-time monitoring of the condition of the electrode/tissue interfaces to enhance interpretation of captured EEG signals.

Abstract: A defibrillation system for use in treatment of ventricular fibrillation includes at least one sensor to measure heart rhythm; at least one applicator to apply a defibrillation pulse to a patient; and at least one processor in communication with the sensor and the applicator to determine a first value related to the rate of change of a leading edge of a lagged phase space reconstruction of ventricular fibrillation heart rhythm measured over a period of time.

Abstract: Systems and methods are provided for predicting the onset of postoperative atrial fibrillation (AF) from electrocardiogram (ECG) data representing a patient. A signal processing component determines parameters representing the activity of the heart of the patient from the ECG data. A feature extraction component calculates a plurality of features useful in predicting postoperative AF from the determined parameters. A classification component determines an AF index for the patient from the calculated plurality of features. The AF index represents the likelihood that the patient will experience AF.

Abstract: This document describes, among other things, systems and methods for characterizing a tachyarrhythmia. A method comprises obtaining a current first primary characterization of the tachyarrhythmia and a current first primary confidence level of the current first primary characterization, obtaining a current second primary characterization of the tachyarrhythmia and a current second primary confidence level of the current second primary characterization, and determining a current secondary characterization using the current first primary characterization, the current first primary confidence level, the current second primary characterization, and the current second primary confidence level.