Abstract: Method and apparatus that uses dual-chamber (RA-RV), three-chamber (BiA-RV, or RA-BiV), or four-chamber (BiA-BiV) implantable cardiac devices including pacemakers, defibrillators and cardioverters, which stimulate cardiac tissue electrically to control the patient's heart rhythm. The method and apparatus are further configured to create a far-field intra-atrial electrogram (AEGM) and a far-field intra-ventricular electrogram (VEGM) that are independently filtered, scaled, and then summed to form a composite far-field electrogram.

Abstract: An implantable medical device that measures respiration parameters based on transthoracic impedance signals, and converts transthoracic impedance signals into a time series of digital values which is filtered with morphological operators to separate the signal into a respiratory component and a cardiac component. Metrics are generated based on the filtered impedance values such as respiratory rate, I/E ratio, tidal volume and minute ventilation.

Abstract: Device for classifying tachyarrhythmia that obtains pre-defined values, monitors atrial intervals and compares lengths of each interval with pre-defined value IL, stores length of atrial interval if length is shorter than IL, in case X of most recent Y number of atrial intervals have length shorter than IL, evaluates most recent <=N atrial intervals with length <IL and performs test for stored lengths via criteria, classifies atrial tachyarrhythmia as stable if all tested lengths pass >=1 criteria, and controls a cardiac device depending on the classification. Atrial intervals are first evaluated by using the “X-out-of-Y” criterion and subsequently checked for stability after an atrial tachyarrhythmia is detected using “X-out-of-Y” criterion. For stability check, only intervals found shorter than the interval limit are used. Check is based on interval-to-interval comparison rather than as generally practiced, comparisons of individual intervals with the minimum or average of all intervals.

Abstract: A medical device and a method is suggested for assessing the risk of R on T events. The device comprises a memory, input means for acquiring or receiving an electrogram signal and processing means. The processing means are adapted to detect R-wave and T-waves represented by said electrogram, establish a QT-RR regression model based detected R-waves and T-waves, estimate a vulnerable period, and store estimated vulnerable period data in said memory. Likewise, the method comprises the steps of to detecting R-wave and T-waves represented by an electrogram, establishing a QT-RR regression model based detected R-waves and T-waves, estimating a vulnerable period, and storing estimated vulnerable period data.

Abstract: A heart monitor for processing input signals that represent periodically reoccurring events in a sequence of heart cycles. According to the invention graphical data representing a scatter plot of at least two dimensions, one dimension representing interval duration or its inverse and the other dimension representing change of duration or its inverse, respectively, are generated. The scatter plot comprises data points of which each data point represents heart interval duration or its inverse plotted against the change of duration with respect to a neighboring interval or the inverse of said change respectively.

Abstract: Heart monitoring apparatus with sensing stage connectable to intracardiac electrode picking up electric potentials and adapted to process electric signals representing a time course of said potentials, a mechanical action detection stage adapted to generate a geometry signal having a time course reflecting heart chamber's geometry change, an evaluation unit connected to sensing stage and impedance measuring stage and adapted to determine a first and second fiducial point in the time course of said potentials and geometry signal, respectively, both fiducial points belonging to same heart cycle, and to determine a measured time delay between said fiducial points. Evaluation unit adapted to repeat said determined time delay to determine plurality of measured time delays and variance thereof or divergence of the statistical properties of cycle times based on said time course of said electric potentials versus cycle times based on said time course reflecting a change of a heart chamber's geometry.

Abstract: Implantable medical device with an impedance determination unit with constant current/voltage source having current feed terminals connected to electrodes for intracorporal placement which generates measuring current pulses having constant current/voltage, for causing a current through a body via intracorporally placed electrodes, a measuring unit for measuring voltage/current strength of voltage/current fed through body, an impedance value determination unit connected to the current/voltage source and adapted to determine an impedance value for each measuring current pulse, and an impedance measuring control and evaluation unit connected to the impedance determination unit which controls the unit and evaluates a sequence of consecutive impedance values, the impedance determination unit further adapted to determine at least intrathoracic and intracardiac impedance values for same period of time, the intrathoracic values sampled with a lower sampling rate than the intracardiac values.

Abstract: Improving the signal-to-noise ratio of electrocardiogram (ECG) measurements facilitates cardiac beat detection in a human or animal patient. ECG signals measured either on the surface of the skin or subcutaneously from pairs of leads may be combined to calculate a differential signal. The measured signal may also be averaged to produce a second estimate. A point-by-point product of the differential signal and the averaged signal is generated if the sample pair has the same polarity. The product signals feature enhanced signal components and reduced noise components, thus improving the signal-to-noise ratio of the to respective input channels. Product signals are then subjected to peak detection through a conventional auto-sensing approach. Preliminary event detection results from the conditional product signals may then be aggregated, and final sense markers for ECG beat detection may be generated by means of a voting algorithm.

Abstract: A medical device having a sensor for sampling a biological signal, the biological signal representing a signal waveform and forming a waveform vector composed of the biological signal samples, and a memory for storing a least two threshold vectors composed of boundary samples representing at least two boundaries related to the biological signal defining subspaces for the biological signal samples. One threshold vector is an upper threshold vector composed of upper boundary samples and the other threshold vector is a lower threshold vector composed of lower boundary samples. An evaluation unit connected to the sensor determines a similarity index (ASCI) by comparing each of the biological signal samples of the waveform vector to corresponding boundary samples of the threshold vectors, thus determining to which subspace each biological signal sample belongs to and creating a trichotomized signal vector, and calculating the signed correlation product of two trichotomized signal vectors.

Abstract: A system, method and computer-readable storage medium are configured for the detection of electrical signals originating from a human or animal heart. In particular, for monitoring devices, it is desired to obtain electrical signals from a human or animal heart with electrical contacts at the body of an implantable medical device, hence without the need to implant electrical leads to the hearts. Hence, a method, a system and a computer-readable storage medium for detecting electrical signals originating from a human or animal heart is proposed. The method includes the steps of receiving electrical signals in at least two sensing channels, combining the electrical signals for forming a combined channel, extracting a template from the signals of the combined channel, comparing incoming electrical signals with the template, and depending from the result of the comparison, performing at least one of controlling one or more devices and signaling the result.

Abstract: A heart stimulator is adapted to adapt an atrioventricular delay interval or an interventricular delay interval or both during night time by adding a delay interval to a respective daytime interval, and the device statistics for day and night are calculated, stored, and can be displayed separately.

Abstract: An implantable medical device comprises at least two sensing channels for receiving sensed first and second location electrical signals originating from two different locations of a heart. A control unit is connected to the sensing channels and is adapted to process sensed electrical signals originating from first and second locations of the heart. The control unit incorporates an adaptive filter compensator adapted to generate an estimate signal for compensating a far-field contribution of the second location signal to the first location signal, thereby generating an output signal representing a near field signal originating from the first location. A gate is connected to the second location sensing channel and is adapted to enable the adaptive filter compensator only if a predetermined signal is sensed via the second location sensing channel.

Abstract: A medical device for processing physiological signals such as electrocardiograms. The processing includes: sampling a physiologic signal in a first channel with a first sampling rate, simultaneously sampling the physiologic signal in a second channel with a higher sampling rate to thus generate pairs of sampling values, forming the difference between two sampling values of each pair, comparing said difference with a threshold, and generating a noise detection indicator whenever said threshold is exceeded.

Abstract: The invention relates to heart stimulators and implantable atrial pacemakers which utilize a rhythm based atrial capture threshold test wherein in a ventricle based DDI mode a predetermined number of ventricle started atrial and ventricular escape intervals are triggered with an overdrive rate about 20% higher than an intrinsic heart rate. The number of atrial sense events during atrial capture threshold test is counted. Too high of a number of atrial sense events indicates loss of capture due to too small of a pulse strength of the atrial stimulation pulses.

Abstract: A heart monitor for processing input signals that represent periodically reoccurring events in a sequence of heart cycles. According to the invention graphical data representing a scatter plot of at least two dimensions, one dimension representing interval duration or its inverse and the other dimension representing change of duration or its inverse, respectively, are generated. The scatter plot comprises data points of which each data point represents heart interval duration or its inverse plotted against the change of duration with respect to a neighboring interval or the inverse of said change respectively.

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: Device for classifying tachyarrhythmia that obtains pre-defined values, monitors atrial intervals and compares lengths of each interval with pre-defined value IL, stores length of atrial interval if length is shorter than IL, in case X of most recent Y number of atrial intervals have length shorter than IL, evaluates most recent <=N atrial intervals with length<IL and performs test for stored lengths via criteria, classifies atrial tachyarrhythmia as stable if all tested lengths pass >=1 criteria, and controls a cardiac device depending on the classification. Atrial intervals are first evaluated by using the “X-out-of-Y” criterion and subsequently checked for stability after an atrial tachyarrhythmia is detected using “X-out-of-Y” criterion. For stability check, only intervals found shorter than the interval limit are used. Check is based on interval-to-interval comparison rather than as generally practiced, comparisons of individual intervals with the minimum or average of all intervals.

Abstract: Heart monitor for detecting ectopic beats in an input electrocardiogram signal that includes an electrocardiogram signal input and a morphological signal analyzer connected to the electrocardiogram signal input, the analyzer being adapted to generate a first time series of values representing the input electrocardiogram signal, a second signal analyzer adapted to generate generating a modified time series of values representing a trend of values of the first time series and a comparison stage being adapted to compare the first time series with the modified time series to thus detect ectopic beats.

Abstract: A heart stimulator for electrical stimulation of a heart chamber includes a sensing stage sensing excitation of the heart chamber via an electrode lead having an electrode for picking up heart chamber electric potentials, a stimulation pulse generator generating electric stimulation pulses for delivery to the heart chamber via a stimulation electrode, and a control unit connected to the sensing stage and the stimulation pulse generator and being adapted to trigger the stimulation pulses at a controlled stimulation rate. A monitoring stage is provided for preventing too high of a stimulation rate for too long of a period of time, with the monitoring stage being connected to the control unit and being adapted to monitor the controlled stimulation rate, and to override the controlled stimulation rate by a fixed stimulation rate for a predetermined period of time if the average controlled stimulation rate exceeds a predetermined maximum rate.

Abstract: The invention refers to a monitoring device for monitoring and analyzing physiological signals. The monitoring device comprises a transthoracic impedance measurement unit and an evaluation unit connected to the transthoracic impedance measurement unit. The transthoracic impedance measurement unit is adapted to conduct a transthoracic impedance measurement and to generate a transthoracic impedance signal representing a measured transthoracic impedance at consecutive points in time. The evaluation unit being configured to process the transthoracic impedance signal received from the transthoracic impedance measurement unit and to thus generate a respiration signal and to generate therefrom an evaluation signal reflecting at least a diurnal pattern of the respiration rate.