摘要:
A high voltage charger operates in a three-phase cycle. In a first phase, the high voltage charger operates at a fixed frequency. In a second phase, the high voltage charger operates at a variable frequency designed to draw a substantially constant average current from a power source. In the third phase, the high voltage charger returns to fixed frequency operation. The variable frequency is the reciprocal of the sum of an on-time and an off-time of the switch. In one embodiment, the on-time is provided by the time required for the switch to reach a predetermined maximum and the off-time is provided by the time over which a magnetic field in a transformer collapses.
摘要:
A lead for use with an implantable cardioverter/defibrillator system is disclosed. In the preferred embodiment, the lead combines a right ventricular endocardial electrode, a superior vena cava electrode and one or more atrial sensing electrodes on a single catheter lead. The distal end of the lead is transvenously implanted, typically through an incision in the cephalic or subclavian vein. The proximal end of the lead is then tunneled below the fascia to the location of the pulse generator. Ventricular sensing and/or pacing electrode(s) may also be included at the distal end of the combined lead to provide ventricular intracardiac electrogram sensing and bradycardia pacing.
摘要:
An implantable cardiac defibrillator is provided having an energy source, a capacitor, and means coupled to the energy source for charging the capacitor. The capacitor comprises a planar layered structure of anode plates, cathode plates and means separating the anode plates and cathode plates. A polymeric envelope containing electrolyte encloses the layered structure. Electrical contact means extend from the anodes and cathodes to outside the envelope.
摘要:
An implantable medical device includes electrodes coupled to a patient's heart and sensing circuitry having inputs connected to the electrodes for sensing cardiac electrical signals. The sensing circuitry includes a digital waveform analyzer system which performs direct analysis of digitized ECG heart signals from the atrial and/or ventricular channels. This eliminates the need for the system microprocessor to perform direct analysis on raw ECG data. The benefit being that complex software algorithms are not required, saving microprocessor memory space. System current drain is also reduced since the microprocessor need not be active during every ECG sample.
摘要:
An implantable cardiac defibrillator employing a switched capacitor filter stage having charge steering resistors connected in series with corresponding switched capacitors that are coupled to a sensitive node of an operational amplifier. The stored channel charges in associated switches when they are turned off are directed away from the sensitive node. The switches associated with the switched capacitors are operated by control signals having a generally trapezoidal shaped waveform so as to slowly turn off the same, thereby reducing clock feedthrough and charge injection induced offset voltage on the output of the operational amplifier.
摘要:
A heart pacemaker detects pace-terminable tachycardia conditions in the atrium of the heart in accordance with selected high rate, rate stability, sudden onset and sustained high rate criteria. When a pace-terminable tachycardia is detected, programmed treatment modalities are applied to attempt to terminate the tachycardia. The tachycardia is treated by applying timed bursts of electrical pulses in formats defined by programmed primary and secondary treatment modalities. The primary and secondary treatments may be applied in an order which is dependent upon the prior successful treatment of similar tachycardias. The pacemaker may also utilize remembered treatment values which were successfully applied to treat similar tachycardias. The pacemaker may be programmed to restart the primary and secondary modes of treatment in the event that the modes initially failed to terminate a tachycardia. The pacemaker may also be programmed to limit the rate of burst pulses to avoid overstimulating the heart.
摘要:
This is a neurostimulator that is configured to treat epilepsy and other neurological disorders using certain stimulation strategies, particularly changing various pulse parameters, during the imposition of a burst of those pulses. The invention includes the processes embodying those stimulation strategies.
摘要:
An implantable neurostimulator system for treating movement disorders includes a sensor, a detection subsystem capable of identifying episodes of a movement disorder by analyzing a signal received from the sensor, and a therapy subsystem capable of supplying therapeutic electrical stimulation to treat the movement disorder. The system treats movement disorders by detecting physiological conditions characteristic of an episode of symptoms of the movement disorder and selectively initiating therapy when such conditions are detected.
摘要:
A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.
摘要:
A method and system for performing device identification is disclosed. A source signal may be directed from an energy source towards the surface of a device for reflection therefrom. An interference pattern may be detected from the surface of the device, such as by a sensor. A determination as to whether a match exists between the representation of the interference pattern and a stored representation of an interference pattern may be performed. If a match exists, the device may be identified based on the stored representation of the interference pattern. Otherwise, a representation of the interference pattern may be stored and a unique identifier may be assigned to the stored representation of the interference pattern.