Abstract: In a method for classifying IEGM waveforms in dependence of the workload of a patient, a predetermined number of IEGM-signals, each signal extending over at least one segment of one heart beat cycle, are registered, whereafter the IEGM-signals are fed to a neural network and an encoded form of the signals is formed using said neural network. This encoded form is stored in a memory, for use in classifying further registered IEGM-signals. In an active cardiac implant connectable to an implantable electrode arrangement adapted for in vivo delivery of stimulation pulses to a heart, IEGM signals present are obtained from one or more of the electrodes. A pulse generator connected to the electrode arrangement, generates and emits stimulation pulses with a variable stimulation interval between successive stimulation pulses.

Abstract: An active medical implant has a hermetically sealable capsule formed by a first part and a second capsule-closing part, whereby the capsule is arranged to hold a battery unit and an electronics unit, conductors for electrically connecting the battery to the electronics unit and contacts with associated conductors arranged on the exterior of the capsule for connection to electrodes. The first part and the second part are made of an essentially biocompatible material, and a partition wall is arranged to form a first essentially closed space in the first part for the battery unit, and an electrically insulating layer, impermeable to battery chemicals, is arranged on the surfaces of the biocompatible material facing the first closed space. An additional space is formed for the electronics between the capsule-closing part and the partition wall.

Abstract: An electrode device which has a proximal end and distal end, contains of a number of thin, insulated electrical conductors each with a proximal end and a distal end, the conductors being equipped with implantable electrode contacts means which are electrically connected to the conductors. These contacts are designed to be brought into electrical contact with tissue in one or more cavities in a human body. Each conductor in the cable device is supported by a pre-shaped stiffening element which runs along and is connected to the conductor, made of an elastic polymer material, resorbable in vivo, which is biodegradable and biocompatible. The stiffening element imparts an arched shaped to the conductor, at least in the area in which its contact is located, to cause the contact to press against the adjacent cavity wall. The cable device also includes a longitudinal channel in which a stylet can be inserted for temporary, linear stretching of the cable device and the arched sections of its conductors.

Abstract: A device for manipulating a stylet unit for positioning an electrode cable in a body cavity has an elongate housing, an elongate, axial cavity in the housing and an operating slide, axially movable in relation to the housing, for attachment to a proximal end section of a tubular stylet sleeve in a stylet unit. An elongate coil spring is located in the cavity on the proximal side of the manipulation device. The coil spring forms an inner guide channel to prevent the buckling of the free, proximal end section of the stylet of the stylet unit in the cavity.

Abstract: In a method and apparatus for physiological signal processing, a number of measured physiological signals are obtained in vivo from a subject and at least one of these measured physiological signals is supplied to the input of each first signal processing unit in a group of first signal processing units. Within each signal processing unit, the physiological measurement signal (or signals) supplied thereto is/are subjected to at least one transfer function so as to produce a pre-treated signal at the output of that first signal processing unit. The pre-treated signals from all of the first signal processing units are combined in a second signal processing unit so as to produce at least one synthesized ECG signal.

Abstract: An implantable medical device for in vivo electrochemical measurements of blood properties, such as measurements of, inter alia, oxygen pressure, glucose and pH, avoids the problem with the reference electrodes currently in use which cause inflammatory reactions of tissue, by forming the reference electrode of carbon, preferably activated pyrolytic carbon.

Abstract: A stylet unit suitable for stiffening a hollow electrode cable, such as during the introduction and the anchoring of a medical electrode cable in the human body, includes a combination of a pair of flexible, coaxially arranged stylet elements, i.e., a tubular stylet sleeve and an internal stylet, which can be inserted into a channel in the sleeve and whose end section is pre-bent to one side. Both the stylet sleeve channel and moving inner stylet contained therein have sections or segments with non-circular cross-sections, the profile of the stylet's non-circular cross-section, in relation to the profile of the sleeve channel's non-circular cross-section, preventing the stylet from rotating in relation to the surrounding sleeve, at least within the parts of the sleeve in which both the stylet and the sleeve channel have interacting non-circular cross-sections.

Abstract: A stylet unit, which can be introduced into a hollow, flexible component, such as an electrode cable, to stiffen the component and to bend a distal end section is formed by a double stylet combination of a flexible tubular stylet shell and an internal stylet, movably arranged inside the shell's channel, with a pre-curved distal end section. This end section can be set at a retracted internal position inside the stylet shell or at an exposed position outside the shell. The internal stylet's pre-curved distal end section is made of a memory metal and has a radius of curvature which varies longitudinally along the end section. The end section can be in the shape of a spiral, and the memory metal can be made of a nickel-titanium alloy.

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: An electrode cable for implantation in a body cavity has a tube made of a biodegradable, biocompatible polymer material attached to the exterior of the cable, the tube forming a channel for a stylet.

Abstract: A medical implant contains a magnetic field detector with a sensor whose capacitance changes in the presence of a magnetic field with a predefined strength, and a capacitance-controlled unit connected to the sensor. The capacitance-controlled unit sends a measurement signal to a detection unit. If a measurement signal parameter affected by capacitance exhibits a specific change over a predefined period of time, a detection signal is generated by the detection unit to indicate the presence of a magnetic field. The sensor's capacitance also changes when the sensor moves, and this is utilized for measuring activity in an activity measurement circuit connected to the capacitance-controlled unit and for generating an activity signal on the basis of the measurement signal.

Abstract: An appliance for fastening one or more electrode leads in a connector unit of an implantable medical device, for example a heart stimulator, is formed of a wire- or strip-shaped resilient locking member, which is arranged to be inserted and fixed in a cavity in a connector unit, and which is shaped to clampingly engage diametrically opposed circumferential parts of the casing of each electrode lead.

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: An implantable cardiac stimulator has locking device for a pin-like conductor element of an electrode lead, the locking device having a helical coil which can assume a first, locking position, in which it grips the pin-like conductor element inserted into the coil to prevent longitudinal movement of pin-like conductor element, and a second, release position in which the pin-like conductor element is free to move in and out of the coil in relation to the coil's longitudinal axis. The first position is assumed when the coil is not influenced in its helix diameter increasing direction and the second position being assumed when the coil is influenced in its helix diameter increasing direction. The locking device also has a blocking component which only prevents the coil from rotating in the unwinding direction around its longitudinal axis in the locking device.

Abstract: In a magnetic field detector as well as in a combined telemetry and magnetic field detector unit in a medical implant, a magnetic field sensor with a coil and a diode are employed for determining the presence of a magnetic field. For making such a determination, the coil is charged by a source of voltage for a defined period of time, the time for the discharge of the coil through the diode depending on whether a magnetic field is present. A detection signal indicating the presence of a magnetic field is generated if the discharge time is less than a defined time threshold value.

Abstract: A cardiac electrotherapy device comprises an elongated elastic lead body having a distal electrode adapted to be connected to the heart; lead body including a sensor portion at a location adapted to undergo deformations responsive to heart muscles contractions when the lead body is connected to the heart. The lead body forms a high frequency transmission line, having two conductors which are provided with terminals at the proximal end of the lead and which are adapted to transmit high frequency signals from the terminals to the sensor portion of the lead and vice versa. The sensor portion varies its high frequency electric parameters when being subjected to said deformations.

Abstract: An electrode contact device for medical application as a contact device at one end of an electrically insulated conductor or electrode cable for a cardiac pacemaker, has a rotationally symmetrical main body of ceramic material with at least one contact portion of electrically conductive material being formed on the exterior of the main body, and which is in electrical communication with a conductor which can be attached to the contact device. The electrically conductive contact portions on the exterior of the ceramic main body are radially and/or axialy separated from each other and at leaest one of these contact portions is formed by a thin layer of material produced by application of electrically conductive material on a surface area of the main body.

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: A heart stimulator for detecting atrial tachycardia, contains a control device to which are connected an atrial detector, having a blanking period, for detecting atrial events, a ventricular stimulation unit for delivering stimulation pulses in the ventricle, a counter for generating a variable PV interval between a detected atrial event and a stimulation pulse delivered in the ventricle, a time measurement unit for measuring time between two consecutive, detected atrial events and a calculation unit which, in a test mode for determining of whether atrial tachycardia is present, is arranged to cause the counter to generate a PV interval so the PV interval plus the atrial detector's blanking period is equal to half or less than half of an adjustable threshold level PP tachycardia. The time measurement unit sends a detection signal to the control device when a defined number of measured, consecutive PP intervals is less than a defined threshold value PP for the PP interval (threshold value PP tachycardia).

Abstract: A heart pacemaker with improved detection of electrical signals which are used for triggering pacemaker functions, has a detection circuit for registering intracardial heart signals in which certain noise signals having a generally chromatic spectrum are superimposed on the signals to be detected, the detection circuit undertaking an adaptive, non-linear noise filter of those intracardial heart signals for converting the spectrum of the noise signals into an essentially white spectrum. The signals filtered by the non-linear noise filtering are supplied to a matched filter wherein correlation of these signals with a sought signal pattern takes place.