Abstract: A heart stimulator has a stimulation energy delivering assembly, including at least one lead adapted for implantation in contact with cardiac tissue, and an atrial arrhythmia detector, and a control unit connected to the stimulation energy delivering assembly and to the detector. The control unit controls the stimulation energy delivering assembly to deliver at least one atrial arrhythmia abolishing therapy and, if continued atrial arrhythmia is detected, to deliver antithrombus stimulation energy pulses of lower energy than a defibrillation shock, but with different timing and with sufficient energy for producing atrial contraction for increasing hemodynamic blood transportation away from the atrium and for preventing thrombi formation in the atrium. For a patient suffering from a chronic or paroxysmal non-curable atrial arrhythmia, the control unit controls the stimulation energy delivering assembly to deliver the antithrombus energy without any preceding arrhythmia abolishing therapy.

Abstract: Mathematical functions such as recursive autoregression models which include parameters are used for defining the heart signal and any signals disturbing the heart signal, such as polarization signals. By registering, during a predetermined time interval, the electrode signal for determining the parameters for one or more different mathematical functions, the parameters can be used on their own or in combination to determine the activity of the heart, i.e., whether the registered electrode signal corresponds to a stimulated, spontaneous or absence of heart activity.

Abstract: An implantable cardiac stimulator has a connector with at least two terminals, each terminal being connectible to an implantable electrode for delivering stimulation pulses to a heart and/or for sensing cardiac activity signals. The stimulator also has a switch and a control unit which operates the switch, so that one or both terminals are connectible to the pulse generator and/or to an input stage. The control unit identifies a position status for at least one of the electrodes in response to a signal received by the input stage at the time of implantation of the stimulator. The control unit also can select a terminal to be connected to the pulse generator, dependent on the established position status.

Abstract: A tachycardia eliminating apparatus includes a heartbeat detector which detects heartbeats in an input heart activity signal which delivers an output heartbeat signal indicating each detected heartbeat, a tachycardia detector coupled to the output of the heartbeat detector which generates a tachycardia indication signal in response to a detected tachycardia status of a heart as reflected in the heartbeat signal, and a respiratory system stimulator coupled to the output of the tachycardia detector and generating an output respiratory system stimulation signal for stimulating a respiratory system to achieve a stimulated breathing rate, with the ratio of the detected heartbeat rate to the stimulated breathing rate corresponding to a predetermined value.

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: 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: 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: A defibrillator has a pulse-generating device with at least three outputs to which electrodes are connectable for delivering defibrillation pulses. A switching network is provided to reverse the polarity and/or to switch the voltages applied by the pulse-generating device, selectively and at predetermined times, among the electrodes.

Abstract: An electrode device, for intracardiac stimulation and/or defibrillation of heart tissue and/or sensing heart signals in a patient, has a soft, flexible electrode cable with an outer coating of insulation containing at least one elongate conductor connected to an electrode arranged on the electrode cable. In order to attain an electrode device of this kind which is structurally very simple and in which all the electrodes on the electrode cable can be applied to the heart wall in a very simple manner so the entire electrode surface faces the wall and firmly presses against it, the electrode cable is at least partially ribbon-shaped.

Abstract: An implantable electrode system includes a connector for connecting a proximal end of the electrode to an implantable medical apparatus, such as for stimulating living tissue, and a distal end at which a tip electrode is located. The proximal end and the distal end are connected by a conductor which electrically connects the medical apparatus to the electrode tip, and which is surrounded by a flexible insulating sleeve. In order to provide an indifferent electrode having a large surface area relative to the size of the tip electrode, the insulating sleeve is provided with a section formed by an electrically conductive, flexible material, which serves as the indifferent electrode. The flexibility of the electrode system is retained, while providing an indifferent electrode of optional size.

Abstract: In an electrode system for implantation in a heart, both the atrium and ventricle electrically interact with a medical apparatus. The electrode system has a single electrode lead having an atrial electrode at a distal end for implantation in the atrium before the electrode lead is advanced deeper into the heart so that a ventricular electrode in-line with and preceding the atrial electrode along the lead, is connectable in the ventricle of the heart. The electrode lead has a first curvature near the ventricular electrode and a second curvature near the atrial electrode in order to facilitate implantation of the electrode system and reduce mechanical loads on the heart after implantation. The electrode system can also be equipped with defibrillation electrodes and/or physiological sensors, thereby becoming multi-functional.

Abstract: A device for stimulating heart tissue contains a stimulation unit connected via a switching device to an electrode system. The number of connecting lines between the stimulation unit and the switching device is minimized by emitting control signals and stimulation pulses from a common pulse signal output socket of the stimulation unit. The switching device contains a signal discriminator which separates the control signals from the stimulation pulses, the control signals then controlling the switching device such that the stimulation pulses are delivered to a specific part of the electrode system.

Abstract: An implantable defibrillator has a charging circuit which charges a capacitance, electrodes for delivering energy from the capacitance to a heart, and a switching stage for discharging the capacitance through the electrodes and across heart tissue to defibrillate the heart, as needed. A non-inductive current limiter is connected in vivo in the discharge path for limiting the current supplied to the heart tissue to predetermined maximum value.

Abstract: An implantable cardioverter/defibrillator has an electrode system including two electrodes, at least one of the two electrodes being adapted for placement in a peripheral vein of the heart, the peripheral veins constituting the venous side of the coronary vessels running between the base of the heart and the apex of the heart.

Abstract: A device for stimulating heart tissue contains a stimulation unit connected via a switching device to an electrode system. The number of connecting lines between the stimulation unit and the switching device is minimized by emitting control signals and stimulation pulses from a common pulse signal output socket of the stimulation unit. The switching device contains a signal discriminator which separates the control signals from the stimulation pulses, the control signals then controlling the switching device such that the stimulation pulses are delivered to a specific part of the electrode system.

Abstract: An electrode system for a defibrillator avoids the use of a ventricular electrode, and provides efficient utilization of the energy stored in the defibrillator with a beneficial distribution of current in the heart. The electrode system includes three electrodes, at least two of which are intravascular electrodes. One of these intravascular electrodes is placed in the inferior vena cava and the other is placed in the coronary sinus, including its continuation (the great cardiac vein) along the base of the heart. The third electrode can be either an extravascular patch electrode, located in the region of the left ventricle, or an additional intravascular electrode located in the superior vena cava. The intravascular electrodes are devised so that they do not impede the flow of blood in the vein in which they are located.

Abstract: A defibrillation electrode, especially for implantation at an intravascular site in a patient, has a flexible electrode cable containing at least one elongate, electrically insulated conductor with an electrode head disposed at a distal end of the electrode cable, and having at least one defibrillation surface for delivering defibrillation pulses to the patient's heart. The electrode head is constructed so as to be radially expandable and, in an expanded position, defines the contours (surface configuration) of a hollow body so as to provide a defibrillation electrode which is affixable to the vessel in which it is sited, and which has a minimal impact on the flow of blood in that blood vessel.

Abstract: An electrode arrangement has at least two coiled electrode conductors which are mechanically and electrically interconnected in a contact region. Within the contact region, the flights of the coiled conductors are engaged, such as by the flights of one conductor surrounding the flights of the other conductor, or the flights being intertwined, thereby producing the necessary mechanical and electrical connection by means of the spring force associated with the coiled structure of each conductor. The connection of the conductors thereby becomes simpler to assemble, and does not require crimping, and results in a more reliable and flexible connection area.

Abstract: A defibrillation electrode has a flexible electrode cable containing at least one elongated, electrically insulated conductors and having an electrode configuration attached at a distal end of the electrode cable. This electrode device configuration a number of elongated, flexible conductors, pre-shaped into an outward bulging configuration, having first ends anchored adjacent to each other at the distal end of the electrode cable, and second ends anchored adjacent to each other at a common connection point. To attain a defibrillation electrode which can be used for intracardial, epicardial and myocardial stimulation of the heart and which can be rapidly introduced into the patient, and applied to the myocardium or pericardium, with no need for major surgery, the conductors are spatially pre-shaped such that the anchored ends at the common connection point are twisted in relation to the anchored ends at the electrode cable's distal end.

Abstract: In order to be able to set the distribution of current of the defibrillation current across the heart muscle, a defibrillator/cardioverter has n (n.gtoreq.3) electrodes connected to a pulse generator having n-1 outputs with a total of n output terminals to which the electrodes are connected. A measuring unit generates a measured signal dependent on the geometrical arrangement of the electrodes with reference to the heart. This measured signal is utilized for setting the pulse heights of the defibrillation pulses to be simultaneously generated at the outputs.