Abstract: An ischemia detector includes repolarization sensor which senses repolarization of the heart of a patient and delivers corresponding repolarization signals to a detecting unit and a workload sensor which senses the workload of the patient and delivers corresponding workload signals to the detecting unit. The detecting unit identifies a state of ischemia as existing upon the occurrence of a predetermined relation between sensed repolarization and sensed workload.

Abstract: In a method and apparatus for removing data outliers in measured signals in an implanted medical apparatus, such as data outliers produced by GSM disturbance picked up by an implanted cardiac stimulator lead and superimposed on the sensed cardiac activity signal, the signal from the implanted lead is subjected to median filtering. The median filtering minimizes, or eliminates, the effect of highly aberrational data points in the incoming signal, without the necessity of actually removing the components in the signal produced by the disturbance from the incoming signal itself. Since no portion of the actual incoming signal is removed by the median filtering, the data integrity of the sensed cardiac signal is preserved.

Abstract: An implantable defibrillator has an electrode lead system a sensing unit for sensing the condition of the heart and emitting a condition signal corresponding to that condition, a control unit for determining the heart's condition from the condition signal and, if a state of fibrillation is present, sending a command signal to a shock pulse generator, which, depending on the command signal, delivers at least one defibrillation shock to the heart via the electrode lead system. The shock being formal of one or more low-energy pulses with an energy less than 2 Joules and a very high voltage, i.e. more than 1,000 Volts. Each low-energy pulse thus has a voltage greatly exceeding the voltage in a conventional defibrillation shock and less energy than the energy in a conventional defibrillation shock.

Abstract: In a method and apparatus for suppressing electrode polarization components in a sensed cardiac signal, the sensed cardiac signal is added to either a differentiated or autocorrelated sensed cardiac signal and a difference is formed between the original sensed cardiac signal and the autocorrelated or differentiated signal, thereby extracting an evoked response component from the sensed cardiac signal, the evoked response component otherwise being overshadowed by the much higher-amplitude polarization component.

Abstract: In a medical therapy apparatus, such as a pacemaker, a physiological function which is to be artificially controlled by therapy administration has a natural variability associated therewith. The medical therapy apparatus generates a basic therapy which would otherwise be supplied to the subject in the absence of such natural variability. The medical therapy apparatus further includes a non-linear oscillator which emits a chaotic output, the chaotic output of the non-linear oscillator being matched to the variability of the physiological function in order to produce a variability adjustment. The basic therapy is combined with the variability adjustment and a variability-adjusted therapy is then administered to the subject.

Abstract: An implantable medical apparatus includes a therapy unit which produces a medical therapy regimen which is administered by the implantable medical apparatus to a subject. The implantable medical apparatus obtains an electrical signal representing physiological activity of the subject and performs detrended fluctuation analysis on the electrical signal so as to obtain a self-similarity parameter for the electrical signal. Deviations of the self-similarity parameter from a nominal value indicate the severity of the pathology of the subject which the implanted medical apparatus is intended to treat. The self-similarity parameter can be made extracorporeally available for use by a physician to evaluate the effectiveness of a treatment program currently in place, and/or can be supplied to a control unit of the implantable medical apparatus for use in automatically adjusting the therapy regimen administered by the implantable medical apparatus.

Abstract: In a method and apparatus for stimulating and/or diagnosing the heart, a voltage is applied to the heart over at least a selected portion of the heart during an activation interval with a rise and fall, with the voltage having a first derivative with an absolute value that is less than the value of the derivative which, for a patient in question, would trigger the patient's heartbeat, and with a duration from beginning to end of each applied voltage signal of at least 30 ms.

Abstract: An implantable heart defibrillator contains a pulse generator controlled by a control unit for emitting a number of heart stimulation pulses at a rate of several Hertz or more. The control unit causes the pulse generator to emit heart stimulation pulses with an energy content of the same, or somewhat greater, magnitude than conventional pacemaker pulses for a period of time long enough for the entire heart to become refractory.

Abstract: A device for detecting hemodynamic conditions in a heart, in particular conditions corresponding to dangerous arrhythmias contains a sensing unit for a physiological variable, such as blood pressure, the unit emitting a signal on the basis of the variable having an average value, a signal conditioning unit connected to the sensing unit, a calculation unit connected to the signal conditioning unit and a comparator after the calculation unit. The calculation unit is devised to calculate a variability measure relative to the signal's average value, the variability measure being correlated to average blood pressure, and the variability measure is compared in the comparator to an adjustable threshold value corresponding to a specific hemodynamic condition, whereupon the comparator emits an indication signal when the variability measure falls below the threshold value.

Abstract: A device for identifying abnormal conditions in a heart retrograde conduction and tachyarrhythmias in particular, includes a differentiating circuit electrically connected to a heart to be monitored in order to differentiate ECG signals from the heart. The differentiated signal is plotted against the ECG signal. The radius (distance from a point on the resulting curve from the origin of the plot axes) in the resulting curve is calculated in a calculator unit. The radius obtained is then compared with a threshold value in a comparator and a sequence for the progression of the radius in relation to the threshold value is obtained and compared with previously obtained sequences stored in a sequence analyzer.

Abstract: A device for analyzing the function of a heart, containing a measurement unit for generating a first measurement signal related to a first electrical or mechanical heart variable and an evaluation unit for evaluating the measurement signal, further contains a circuitry for generating a parameter signal related to a heart variable, the evaluation unit analyzing the related values for the measurement signal and the parameter signal. The device can be used for detecting a number of functional aberrations, such as bradycardia, tachyarrhythmia, retrograde conduction, ischemia and ectopia, and for controlling pacemakers and defibrillators.

Abstract: A rate-responsive heart stimulator with a variable stimulation interval contains a measurement device which generates a measurement signal corresponding to the volume of blood in a heart during the blood-filling phase (diastole) and a comparator which compares the measurement signal with a defined threshold value corresponding to a defined degree of blood filling. The comparator generates a control signal when the measurement signal reaches the threshold value, the control signal representing the time elapsing since the last stimulation pulse, and controlling the heart stimulator's stimulation interval.

Abstract: Implantable medical device comprising a device for stimulating tissue contractions with adjustable stimulation intensity, whereby the stimulation intensity is set such that a stimulated event is detected after stimulation with a detector device. The detector device detects stimulated tissue contractions in a signal corresponding to the chronological curve of the electrical impedance of the tissue to be stimulated.

Abstract: A method and apparatus for calculating a parameter for a physiological function wherein, given a measurement signal influenced by more than one physiological function parameter, signal components of the measurement signal arising from a parameter not of interest are filtered out such that a period duration inversely proportional to the respective current frequency of the parameter not of interest is continuously identified and a mean value of the measurement signal is continuously formed over the identified period duration.

Abstract: In a method and apparatus for detecting ventricular fibrillation, a measured impedance signal, dependent on the blood volume in the heart, is evaluated, and ventricular fibrillation is assumed to be present if the level of the measured impedance signal falls below a predetermined threshold. This is based on the perception that as the heart fills with blood, given the presence of ventricular fibrillation, the level of the measured impedance signal will decrease. The apparatus also includes circuitry for treating the detected ventricular fibrillation.

Abstract: An impedance measurement, used for controlling the pulse generation rate of the pacer, is obtained by placing an electrode in the ventricular portion, rather than the atrial portion, of the heart. The characteristic p-wave in the electrocardiogram is detected as a rapid inflection or notch in the impedance signal, with a stimulation pulse being generated with a time delay following detection of such a notch.