Abstract: The invention relates to a method and apparatus for fast satellite antenna acquisition via signal identification. The method and apparatus operate by positioning a satellite antenna using signal identification in order to reduce false satellite signal locks and missed detections and speed the acquisition of the correct satellite.

Abstract: The invention relates to a method and apparatus for fast satellite antenna acquisition via signal identification. The method and apparatus operate by positioning a satellite antenna using signal identification in order to reduce false satellite signal locks and missed detections and speed the acquisition of the correct satellite.

Abstract: An implantable cardiac stimulation device having an improved multi-level electronic module is disclosed. The multi-level module comprises at least two stacked internal substrates for mounting electronic components within a confined region formed between the two stacked substrates. Placement of the two stacked substrates creates an opening establishing fluid communication between the confined region and an exterior of the electronic module. A polymer dielectric coating, such as parylene, is vapor deposited over the entire electronic module which penetrates the confined region via the opening. The parylene provides enhanced protection against dielectric breakdown between the electronic components and their interconnections thereby enabling smaller separation distances between the electronic components. The parylene also provides support for the electronic components and their interconnections while acting as a moisture barrier and a particle getter.

Abstract: An implantable cardioverter defibrillator (ICD) device provides capacitor reformation by successively charging and leaking its output capacitor either a specified number of times or until a specified charge remains on the output capacitor after leakage. The ICD delivers therapy with minimal delay should an arrhythmia detection occur during the capacitor reformation process by anticipating an arrhythmia detection and dumping the reformation energy stored on the output capacitor to an acceptable level as soon as a possible arrhythmia detection is anticipated. The ICD further measures the energy level of the last charge delivered following each delivery so that the energy level of subsequent charges may be adjusted to provide optimal therapy to the patient if prior therapy attempts have not successfully terminated the arrhythmia.

Abstract: A microprocessor-controlled implantable cardiac stimulating device having a normal mode, an intermediate mode, and a backup pacing mode is provided. The device switches from one mode to another in response to the detection of any one of an address error, parity error, opcode error, or watchdog timer error. The microprocessor is shut down during the delivery of a cardioversion or defibrillation shock in order to prevent signals produced by the microprocessor from being subjected to transient electrical signals. The interrupt registers of the microprocessor are also disabled during the delivery of a cardioversion or defibrillation shock. In an alternative embodiment, an implantable cardiac stimulating device is provided with redundant microprocessors in order to detect malfunctions of the microprocessors.

Abstract: An implantable cardiac stimulation device that has automatic functions in each of two different sets of microprocessor operating code. Following implantation, a first mode of operation executes a first set of operating code, stored primarily in RAM, and performs software error detection. Upon detection of an error, the microprocessor is caused to enter a second (backup) mode of operation, where it executes a second set of operating code, which is retained in read-only memory (ROM). Thus, in the unlikely event of error detection, the implantable device is still fully functional in its second mode to provide automaticity, e.g., to select therapies for different heart condition and provide rate-responsive pacing that tracks physiological requirements. If an error is detected in the second mode, than a third mode of operation (e.g., fixed-rate VVI pacing) is enabled.

Abstract: A microprocessor-controlled implantable cardiac stimulating device having a normal mode, an intermediate mode, and a backup pacing mode is provided. The device switches from one mode to another in response to the detection of any one of an address error, parity error, opcode error, or watchdog timer error. The microprocessor is shut down during the delivery of a cardioversion or defibrillation shock in order to prevent signals produced by the microprocessor from being subjected to transient electrical signals. The interrupt registers of the microprocessor are also disabled during the delivery of a cardioversion or defibrillation shock. In an alternative embodiment, an implantable cardiac stimulating device is provided with redundant microprocessors in order to detect malfunctions of the microprocessors.

Abstract: A low-power delta modulator analog-to-digital converter is provided that is suitable for use in a cardiac stimulating device for monitoring intracardial signals. The delta modulator consumes less power than previously available delta modulators because portions of the delta modulator circuitry are shut down when the signal to be digitized is not rapidly varying. The device uses slow clock pulses for sampling the input signal and subsequently digitizes the sampled signal using a faster clock. After a sampled signal has been digitized, the result is held until the next slow clock pulse. Power consumption is reduced since the delta modulator does not draw substantial amounts of power during this holding period. Further, the output of the delta modulator reflects the magnitude of the change in the analog input, with a separate bit for representing direction.

Abstract: An intelligent patch electrode having a plurality of sensor electrodes for use with an implantable defibrillator. The sensor electrodes are disposed in an array and connected to a microcircuit to sense a depolarization wave as it propagates through the ventricular tissue. The timing, direction of propagation, and point of initiation of successive depolarization waves can also be monitored.