Medtronic, Inc.

Richard P Houben

Koen J Weijand

Alexis C Renirie

Vincent Larik

Frank Van Leeuwen

Jeff Wilkinson

Information derived from ECG signals and EEG signals may be employed in combination to reliably predict the onset, or to indicate the presence of, hypoglycemia in a human patient. In one embodiment, ECG and EEG signals are processed and the information derived from them is combined to determine whether a patient suffering from diabetes is undergoing a hypoglycemic event, or whether such an event is imminent. Input data from the patient or a health care provider may also be used to increase the accuracy and reliability of the system. Detection of a hypoglycemic event by the system can result in the output of an alarm signal and/or the delivery or administration of a beneficial agent such as insulin, glucagon or diazoxide to the patient. The system may be implantable, external, or a combination of external and implantable components. The control strategy of the present system is preferably microprocessor based and/or implemented using dedicated electronics. In another embodiment, the glycemic state of the patient is continuously or relatively continuously monitored and controlled by the system. The system may contain any of a number of different types of feedback control systems for monitoring the glycemic state of a patient and controlling same, such as fuzzy logic systems, adaptive systems, reinforcement learning systems, and the like.

System and method for monitoring and controlling the glycemic state of a patient

Floating and non-floating on-chip capacitors are formed by vertical walls and/or large aspect ratio deep trenches disposed in semiconductor material. By optimizing the through spacing and substrate voltage, a very small parasitic to intended capacitance ratio may be obtained. Capacitors so formed may be used as on-chip charge storage and other types of on-chip capacitors, and eliminate or reduce the number of off-chip capacitors that would otherwise be required. The deep trench capacitors find particularly efficacious application in implantable medical devices where volume, cost and electrical energy consumption must be minimized, and preferably have capacitances which range between about 10 nF and about 1000 uF.

Deep trench semiconductor capacitors having reverse bias diodes for implantable medical devices

There is provided a telemetry system with a receiver which enables detection of pulsed high frequency data (hf) signals in a manner which suppresses noise which may be present within the high frequency bandwidth. The transmitter carrier, which may be subject to some instability, is encoded at a symbol rate which is generated at a lower frequency than the hf, but which is reliably stable. The receiver detects the phase of each received hf pulse, and generates a phase-locked signal which is synchronized to the transmitter symbol signal. The phase-locked signal in turn is used to demodulate the received pulsed signals. In a specific DSP embodiment, the phase-lock loop has a numerically controlled oscillator which has a center frequency which corresponds to the aliased phase difference between the hf carrier phase and the phase of each pulse, thereby obtaining a signal which carries information as to the exact symbol rate. This information is used either to calculate the timing of a narrow window which gates a pulse detector coincident with each next expected symbol time, or to trigger generation of a replica signal which is used in the detect circuit, thereby providing high resolution detection of the pulses and good noise rejection.

Telemetry system with phase-locking noise suppressing receiver

There is provided an implantable system and method for monitoring pancreatic beta cell electrical activity in a patient in order to obtain a measure of a patient's insulin demand and blood glucose level. A stimulus generator is controlled to deliver stimulus pulses so as to synchronize pancreatic beta cell depolarization, thereby producing an enhanced electrical signal which is sensed and processed. In a specific embodiment, the signal is processed to determine the start and end of beta cell depolarization, from which the depolarization duration is obtained. In order to reduce cardiac interference, each stimulus pulse is timed to be offset from the QRS signal which can interfere with the pancreas sensing. Additionally, the beta cell signals are processed by a correction circuit, e.g., an adaptive filter, to remove QRS artifacts, as well as artifacts from other sources, such as respiration. The thus obtained insulin demand signal is used either to control delivery of insulin from an implanted insulin pump, or to control ongoing pancreatic stimulation of a form to enhance insulin production.

System for pancreatic stimulation and glucose measurement

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.

Implantable device telemetry system and method

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. In another embodiment, the system responds to a good intake signal, either externally or internally generated, by going through a time response algorithm to provide a stimulation-enhanced insulin response which simulates the natural response. In yet another embodiment, the functionality of an islet transplant is continually monitored, and performance data is logged and down loaded on command to an external programmer. The stimulation of patient pancreatic cells may be combined with administration of a hypoglycemic agent.

System and method for enhancement of glucose production by stimulation

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. The invention can be performed with either analog or digital embodiments, analog embodiments providing for lower power consumption.

Pacemaker with morphological filtering of sensed cardiac signals

A system and method for sensing and providing an indication of one or more diabetes-related blood constituents of a patient, the system being based upon an ECG sensor which processes patient ECG signals, either surface, or intracardiac or epicardial, for determining a measure of a blood constituent such as insulin or glucose, or both insulin and glucose. The system has processing capability for correlating selected parameters of the ECG signal with patient blood insulin or blood glucose, to provide the insulin or glucose level. Additionally, the system is provided with input capability for enabling the patient to input data such as the time of meal intake, which is representative of glucose intake, which data is incorporated in making a determination of patient insulin need. The system can be in a first external wearable embodiment, or in a second implantable embodiment which utilizes a pacing-type lead for picking up intracardiac or epicardial signals. In either the wearable or implantable embodiment, the output response may be simply an indication of patient insulin and/or glucose need provided by an external display, and may also include automatic control of insulin injection to the patient.

Growing community of inventors

Berg & Terblijt, Netherlands

Richard P Houben