Abstract: Methods and devices (e.g., pacemakers or ICDs with pacemaker functions) are provided for maintaining a high percentage of bi-ventricular pacing after a pacemaker switches from an atrial tracking bi-ventricular pacing mode to a non-atrial tracking bi-ventricular pacing mode, wherein the ventricles are paced in accordance with a mode switch base rate (MSBR) during the non-atrial tracking ventricular pacing mode. Monitoring is performed to determine whether or not pacing in according with the MSBR satisfies a minimum acceptable pacing criterion (MAPC). The MSBR is increased and pacing is performed in accordance with the increased MSBR, when the MAPC is not satisfied. The MSBR is decreased (e.g., periodically) and pacing is performed in accordance with the decreased MSBR when the MAPC is satisfied.

Abstract: Improved pre-pulse pain inhibition (PPI) techniques are provided for reducing pain caused by cardioversion shocks, including a technique for determining preferred pulse durations for high voltage PPI pulses. Techniques for generating both low voltage and high voltage PPI pulses are also set forth. In one example, a train of low voltage pre-pulses is delivered to the heart, followed by a single high voltage “sliver” pulse, followed by a main high voltage cardioversion shock. The train of low voltage pre-pulses is delivered while alternating between atrial and ventricular tip electrodes, with the device housing used as a return electrode. The sliver pulse, which may be only 20 or 30 microseconds in duration, is instead delivered between electrodes implanted in the heart, such as between the RV coil and SVC coil. The main shock is delivered between the RV coil and the device housing.

Abstract: A system and method that rejects interference in a direct-sequence spread spectrum communications system. The system and method implement smooth transitions from hop to hop with minimal transient degradation. Adaptive interference suppression is achieved using a suppression filter and an adaptive algorithm that processes the output of the suppression filter and an estimate of the hopping frequency of the interfering signals to switch between interference filter coefficients of the suppression filter. This creates a notch at the carrier frequency of the interfering signals and rejects interference contained in the communication signals. The interference rejection filter hops with the frequency-hopped spread spectrum interfering signals to maintain its interference rejection capability.

Abstract: Blind narrow-band interference cancellation apparatus and methods that implement an algorithm that adapts an antenna array or a finite impulse response equalizer, or a combination thereof, to cancel narrow-band interference in a communication signal. The apparatus and methods comprise an algorithm for removing an unknown narrow-band interferer from a communications signal of interest, so that the desired signal may be lock on to. In implementing the cancellation apparatus and methods, the received signal is oversampled either in time or in space. This oversampled signal contains a statistically white component (the signal of interest) and a correlated component (the narrow-band interferer). A prediction-error filter is formed using correlation statistics of the oversampled signal. Filtering the oversampled signal produces an output that is statistically white, containing most of the signal of interest, and a small portion of the interference.

Abstract: An autocalibrating modulating array transmitter 10 and autocalibration method 30. The autocalibrating modulating array transmitter is used to gain-balance and phase-balance parallel amplifier stages 11 for coherent combining. The novelty of the autocalibration technique involves periodic substitution of calibration symbols into a valid data stream, the use of only the error magnitude (as opposed to magnitude and phase), and a random selection of either gain or phase adjustments to avoid limit cycles.

Abstract: An autocalibrating modulating array transmitter 10 and autocalibration method 30. The autocalibrating modulating array transmitter is used to gain-balance and phase-balance parallel amplifier stages 11 for coherent combining. The novelty of the autocalibration technique involves periodic substitution of calibration symbols into a valid data stream, the use of only the error magnitude (as opposed to magnitude and phase), and a random selection of either gain or phase adjustments to avoid limit cycles.

Abstract: Coherent combining apparatus and methods that do not require training to adapt combining weights. The approach employed in the present invention uses phase-lock loops to demodulate input signals. The phase-lock loops are coupled so that their outputs are phase coherent. The outputs of the phase-lock loops are summed to obtain a coherent combining of the input signals. Exemplary embodiments of the present invention comprise two or more phase-lock loops having signal inputs and I and Q data outputs. A combiner sums the I and Q data output by the two or more phase-lock loops. A common decision circuit feeds back the summed output of the combiner to the two or more phase-lock loops and generates phase coherent output signals.

Abstract: An apparatus and method for defibrillation utilizes a ratio of short and long window moving averages to provide optimum selection of the time for shock delivery.

Abstract: An antitachycardia device, either implanted or external, which delivers a fixed pulse width truncated exponential waveform defibrillation shock and automatically adjusts the pulse duration based upon the impedance measured or calculated following a delivered shock. The apparatus operates by measuring or calculating the high voltage system impedance, selecting a pulse width for that impedance value and using a pulse width derived from the selected pulse width for the next defibrillation shock.

Abstract: A cardiac therapy method with duration timer is disclosed, using an implanted cardiac pulse generator. A patient's heartbeat is sensed and the intervals between heartbeats are averaged. The number of temporary storage bins, in the form of RAM locations, are provided, including a sinus bin, a low rate tachycardia bin, a high rate tachycardia bin, and a fibrillation bin. The storage bin corresponding to the cardiac rhythm band of the determined average heartbeat interval is incremented. A maximum count limit is assigned to each storage bin. When the first bin reaches its maximum count limit, a diagnosis of the patient's cardiac rhythm is provided. Upon detection of a tachycardia, a duration timer is started and the tachycardia is treated in accordance with a programmed routine. If sinus is detected during the predetermined time period, then the duration timer is cleared.

Abstract: A cardiac therapy method is disclosed, using an implanted cardiac pulse generator. A patient's heartbeat is sensed and the intervals between heartbeats are averaged. The number of temporary storage bins, in the form of RAM locations, are provided, including a sinus bin, a low rate tachycardia bin, a high rate tachycardia bin, and a fibrillation bin. The storage bin corresponding to the cardiac rhythm band of the determined average heartbeat interval is incremented. A maximum count limit is assigned to each storage bin. When the first bin reaches its maximum count limit, a diagnosis of the patient's cardiac rhythm is provided. Upon detection of a tachycardia, a duration timer is started and the tachycardia is treated in accordance with a programmed routine. If sinus is detected during the predetermined time period, then the duration timer is cleared.