Abstract: A heart stimulation system comprises an electrode lead comprising at least one stimulation electrode a stimulation pulse generator adapted to generate electric stimulation pulses and being connected to said electrode lead for delivering electric stimulation pulses to at least one chamber of a heart via said stimulation electrode, and a control unit that is connected to said stimulation pulse generator. The electrode lead is a coronary sinus lead adapted to be placed inside the coronary sinus of a human heart and comprises an ultrasonic transducer that is adapted to measure a velocity of blood flow across a mitral valve of a human heart and that is placed on said coronary sinus lead such that the ultrasonic transducer is placed in the coronary sinus or the great cardiac vein when the coronary sinus lead is in its implanted state.

Abstract: A heart stimulation system comprises an electrode lead comprising at least one stimulation electrode a stimulation pulse generator adapted to generate electric stimulation pulses and being connected to said electrode lead for delivering electric stimulation pulses to at least one chamber of a heart via said stimulation electrode, and a control unit that is connected to said stimulation pulse generator. The electrode lead is a coronary sinus lead adapted to be placed inside the coronary sinus of a human heart and comprises an ultrasonic transducer that is adapted to measure a velocity of blood flow across a mitral valve of a human heart and that is placed on said coronary sinus lead such that the ultrasonic transducer is placed in the coronary sinus or the great cardiac vein when the coronary sinus lead is in its implanted state.

Abstract: A stimulation arrangement having a stimulation unit for the delivery of electrical pulses for the stimulation of body tissue and an evaluation unit which receives electrical signals in conjunction with the delivery of a stimulation pulse and evaluates same for checking a stimulation success, wherein the evaluation unit detects in the received signal such signal features which characterize a lack of stimulation success and delivers a corresponding signal.

Abstract: A stimulation arrangement having a stimulation unit for the delivery of electrical pulses for the stimulation of body tissue and an evaluation unit which receives electrical signals in conjunction with the delivery of a stimulation pulse and evaluates same for checking a stimulation success, wherein the evaluation unit detects in the received signal such signal features which characterize a lack of stimulation success and delivers a corresponding signal.

Abstract: A method for discriminating between externally-radiated, electromagnetic interference signals and electromedical scanning signals comprises the following steps: the preamplification of the scanning signals by means of two preamplifiers; the comparison of the preamplified scanning signals by a comparator; the phase-sensitive evaluation of the comparator output signal for differentiating between scanning signals and interference signals; the feedback of the comparator output signal to the amplification control of the preamplifiers such that the comparator output signal is minimized when an interference signal is detected.

Abstract: A rate responsive implantable pacemaker generates a metabolic demand parameter which is converted into a corresponding metabolic indicated parameter. The parameter is used to determine certain characteristics related to an exercise period and the patient, including exercise duration and intensity. These characteristics are used to dynamically calculate an exercise recovery period during which the pacing rate is elevated above a rate indicated by the metabolic parameter. Preferably, fuzzy logic circuitry is used for this purpose.

Abstract: A rate responsive implantable pacemaker generates a metabolic demand parameter such as a thoracic impedance which is converted into a corresponding metabolic indicated parameter. During the conversion, intermediate parameters, such as either tidal volume and respiration rate, or a derivative of the metabolic demand parameter are used by a cross-check circuit to insure that artefacts due for example to stroke volume noise are eliminated. The peak limiter is used to limit the metabolic indicated rate to an acceptable range. Both protection circuits use fuzzy logic components.

Abstract: A rate responsive pacemaker includes a noise sensor for sensing noise on the leads. If noise is detected, the pacemaker switches to a mode wherein a metabolic demand parameter is ignored. The noise is preferably detected by using test signals which are also used to measure the metabolic demand parameter.

Abstract: A rate responsive pacemaker includes a detector for detecting the anaerobic threshold of the patient. The threshold can be logged or can be used to manipulate the pacing regime of the pacemaker. The detector may include two metabolic demand sensors: one which is sensitive to the anaerobic threshold and one that is not. In this manner, the anaerobic threshold can be detected by monitoring the correlation between the two parameters. The parameter sensitive to the anaerobic threshold may be a parameter dependent on the patient's breathing cycle, such as minute volume, while the other parameter is preferably a threshold dependent on the sympathetic control of the body such as the QT interval.

Abstract: In an implantable rate responsive pacemaker a metabolic demand parameter is mapped in accordance with a rate response function into a corresponding metabolic indicated rate for pacing a patient's heart. In addition, a physical fitness monitor is also provided which monitors the patient's physical fitness and generates a long term true and accurate physical indicia. This indicia is used to adjust the rate response function so that it is automatically adjusted to the physical fitness of the patient.

Abstract: An implantable rate responsive pacemaker uses the physiological demand parameter to determine the classification of the patient (i.e., his degree of congestive heart failure). For this purpose, the parameter is monitored for extended time periods (i.e., several days) to determine the levels for said parameter corresponding to different levels of physical activity, such as maximum physical activity or rest. The variation in these levels is then translated into corresponding classification (0-IV) using a preselected criteria.

Abstract: In a cardiac pacemaker, a monitoring window is defined during the a-v delay during which signals sensed in the ventricular channel are monitored. If an abnormal signal is sensed during this window, certain features of this signal are analyzed to determine its origin, such as PVC. If the signal cannot be categorized as a known signal, a safety pacing pulse is applied.

Abstract: An implantable pacemaker receives electrical signals from a patient's heart through an electrode, the signals being either intrinsic cardiac signals or repetitive noise signals, due for instance to electromagnetic inference. The pacemaker includes circuitry for determining if the signals from the electrode are cardiac in origin or not by extracting certain signal characteristics from the signals. For example, the noise signals produced by EMI are repetitive, i.e., they have a fairly constant amplitude except for the initial peak. On the other hand cardiac signals have at most three peaks of decreasing amplitudes. These characteristics are used by the determined circuitry to differentiate between cardiac and noise signals. While this determination is taking place, the received signals are stored or delayed. Signals identified as cardiac signals are processed. The processed signals are compensated for the delay caused by the noise detection circuitry.

Abstract: In a dual sensor pacer/defibrillator the output of a metabolic sensor is used to calibrate the output a second sensor over a long time period. In this manner the two sensor outputs track accurately the metabolic demand of the patient and no recalibration by a clinician is necessary.

Abstract: A cardiac stimulation system is provided which delivers long term cardiac therapy without a personal supervision by a physician. The system includes a cardiac stimulation device implanted in a patient and an external device in constant or periodic communication with the cardiac device. The external device is used to control the pacemaker operation. The external device receives updates of the condition of the patient and the operation of the cardiac device and the therapy provided by the cardiac device. This information is transmitted by the external device over a standard telephone network which may consist of hardwired network, a cellular network, or a combination thereof to a remote control device operating near the physician and/or a monitoring station used for monitoring and data logging information from a plurality of patients. The cardiac device, through the external device can also communicate directly and exchange information with the patient over an RF channel.

Abstract: In a dual chamber implantable pacemaker, the peak amplitude of the atrial intrinsic signals are monitored and used to generate a short term and a long term indicia indicative of the intrinsic signals' variability and deviation from normal sinus rhythm peak amplitudes. The two indicia are combined to generate a single indicia which is then used to categorize the state of the atrium as one of several conditions such as flutter/flubber, coarse atrial fibrillation or fine atrial fibrillation. The categorization is used by a microcontroller for generating the proper pacing pulses and may also be used as a criteria for mode switching between a first mode wherein synchrony between the atrium and ventricle is maintained and a second mode pacing is performed at a fixed rate or one determined by the metabolic indicator.

Abstract: A graphic user interface for a cardiac implant, such as an implant programmer, includes image generators for generating multiple images on a screen, each image corresponding to as representation of a parameter related to the operation of the implant or a cardiac function, and an indicia generator for superimposing on the images an indicia indicative of the interrelation between the parameters. The indicia allows a user to obtain a clear understanding and appreciation of the cause and effect rules between various cardiac parameters and/or functions, the parameters or functions could be actual, i.e., obtained from the implant and/or the patient's heart, or they can be simulated to provide the user an indication on how the pacemaker will operate under these simulated conditions parameters.

Abstract: A system for providing cardiac stimulation to a patient includes an implantable stimulation device with a microprocessor and a separate programmer. The stimulation device includes a memory holding substantially all the information necessary to program the device, including device specific information such as various modes of operations, the operational parameters associated with each mode, as well as patient specific information. All this information is transferred to the programmer for display and for generating a program. The program is than transferred back to the device for operating its microprocessor. In this manner, any programmer can be used to generate a program for any cardiac stimulation device without the need for providing specific programming information to the programmer for each specific device.

Abstract: A diagnostic device for providing a prognosis of patient with an implanted cardiac device includes a data bank for storing statistical data relating various symptoms characterizing cardiac problems and associated complications. The device further includes an input device so that a clinician can enter patient specific data including his symptoms. A set of rules stored in a memory are used to provide a diagnosis for the patient based on the statistical data. Preferably the diagnostic device is incorporated in a programmer for a pacemaker or other implantable cardiac device.

Abstract: The cardiac output of a paced heart is optimized by measuring a parameter indicative of the volume of blood in a heart chamber as a function of a pacing parameter. The pacing parameter is adjusted so that the heart pumps the maximum volume at different rates for hearts with debilitating pathologies. This pacing parameter is then used for controlling the pacing pulses for pacing the heart. Preferably the volume parameter is the paced depolarization integral and the pacing parameter is the A-V delay.