Abstract: There is provided an improved telemetry system for use with implantable devices such as cardiac pacemakers and the like, for two-way telemetry between the implanted device and an external programmer. The system employs highly energy efficient oscillators with encoding circuits for synchronous transmission of data symbols, which symbols form the telemetry carrier. The system provides improved circuits for higher density data encoding of sinusoidal symbols, including improved combinations of BPSK, FSK, and ASK encoding. Embodiments of transmitters for both the implanted device and the external programmer, as well as modulator and demodulator circuits, are also disclosed, and specifically include oscillators which switch capacitors between a tank circuit and a recharge path, the switching being controlled to occur at moments of substantially zero coil current, thereby providing high efficiency operation.

Abstract: There is provided a system for automatically responding to insulin demand without any need for external monitoring or injecting of insulin into the diabetic patient. The system provides for sensing glucose levels internally, and responding by stimulating either the pancreas or a transplant of pancreatic islets in order to enhance insulin production. The enhancing stimulation is delivered at a rate greater than the burst rate, or is otherwise controlled so that the depolarization burst constitutes a greater portion of each islet electrical cycle, thereby resulting in increased insulin production. The system also provides for continuous glucose monitoring, and reacts to sensed hypoglycemia by delivering stimulus pulses timed to reduce the burst durations, and thus to inhibit insulin production.

Abstract: A system and method are provided, particularly useful for an implantable cardiac pacemaker, for morphological filtering of sensed signals to reliably and accurately identify one or more specified wave portions of the sensed signals. In a first pacemaker embodiment, morphological filtering is done on the sensed atrial signal, whereby the P-wave peak is discriminated out, with the resulting signal minus the P-wave peak being then subtracted from the inputted atrial signal to provide the atrial peak, thereby effectively eliminating sensing of FFR-wave portions. By setting the morphological filter length to correspond to about the duration of the P-wave peak, or just slightly larger, and by adjusting sampling frequency to correspond to cardiac rate variations, there is provided optimized filtering consistent with low power consumption in an implantable device. In other embodiments, FFR-waves, T-waves, VT, SVT and sinus tachycardia are identified by using templates matched to the wave to be identified.