Abstract: An external transmitter circuit drives an implantable neural stimulator having an implanted coil from a primary coil driven by a power amplifier. For efficient power consumption, the transmitter output circuit (which includes the primary coil driven by the power amplifier inductively coupled with the implanted coil) operates as a tuned resonant circuit. When operating as a tuned resonant circuit, it is difficult to modulate the carrier signal with data having sharp rise and fall times without using a high power modulation amplifier. Sharp rise and fall times are needed in order to ensure reliable data transmission. To overcome this difficulty, the present invention includes an output switch that selectively inserts a resistor in the transmitter output coil circuit in order to de-tune the resonant circuit only during those times when data modulation is needed. Such de-tuning allows sharp rise and fall times in the data modulation without the need for using a high power modulation amplifier.

Abstract: An external transmitter circuit drives an implantable neural stimulator having an implanted coil from a primary coil driven by a power amplifier. For efficient power consumption, the transmitter output circuit (which includes the primary coil driven by the power amplifier inductively coupled with the implanted coil) operates as a tuned resonant circuit. When operating as a tuned resonant circuit, it is difficult to modulate the carrier signal with data having sharp rise and fall times without using a high power modulation amplifier. Sharp rise and fall times are needed in order to ensure reliable data transmission. To overcome this difficulty, the present invention includes an output switch that selectively inserts a resistor in the transmitter output coil circuit in order to de-tune the resonant circuit only during those times when data modulation is needed. Such de-tuning allows sharp rise and fall times in the data modulation without the need for using a high power modulation amplifier.

Abstract: An implantable system control unit (SCU) includes means for measuring tissue impedance or other condition to determine allograft health, in order to predict or detect allograft rejection. The SCU also includes at least two electrodes coupled to means for delivering electrical stimulation to a patient within whom the device is implanted, and may also include a reservoir for holding one or more drugs and a driver means for delivering the drug(s) to the patient. In certain embodiments, the system is capable of open- and closed-loop operation. In closed-loop operation, at least one SCU includes a sensor, and the sensed condition is used to adjust stimulation parameters. Alternatively, this sensory “SCU” sounds an alarm, communicates an alarm to an external device, and/or is responsive to queries regarding sensed information, such as tissue impedance.

Abstract: The stimulation device blanks T-waves from the atrial channel of an electrical cardiac signal by employing a T-wave blanking interval localized to the expected location and duration of the T-wave. To this end, the stimulation device determines the average interval between an R-wave and a T-wave in the patient in which the device is implanted and also determines the average duration of a T-waves within the patient. A T-wave blanking interval is initiated following the average R-T interval subsequent to detection of an R-wave and lasts for a period of time equal to the average T-wave duration. In this manner, highly localized T-wave blanking is achieved permitting P-waves or other atrial signals to be detected during remaining non-blanked portions of the atrial channel of the cardiac signal at least for the purposes of atrial rate detection. The relatively short T-wave blanking interval of the invention is particularly well suited for use in combipolar sensing systems.

Abstract: An implantable cardiac stimulation device and method provides reliable sensing of cardiac events to support cardiac pacing or fibrillation detection. The device comprises a sensing circuit that senses the cardiac events in accordance with a plurality of threshold characterizing parameters. A parameter control adjusts the threshold parameters responsive to the rate of the sensed cardiac events in a manner which precludes positive feedback to prevent continued oversensing, undersensing, or noise sensing.

Abstract: An external programmer is provided with the capability of automatically resetting the programming state of an implantable medical device to a previous programming state. To this end, the pacemaker maintains parameters representative of current and past programming states. In response to a physician-initiated reset function using an external programmer, the pacemaker transfers information pertaining to the programming states to the external programmer along with a pointer identifying the current state. The physician selects one of the previous programming states and the external programmer then updates the pointer to identify the selected state and transmits the pointer back to the pacemaker. The pacemaker accesses the programming parameters stored therein corresponding to the programming state identified by the new pointer and is reprogrammed. Accordingly, the programming state of the pacemaker is reset to the previous programming state without requiring manual reentry of the parameters.

Abstract: An atrial, anti-arrhythmia system and method are provided. The system comprises: at least two electrodes attached to the atrium for providing independently controlled stimulus through each electrode; detection circuitry that can sense atrial fibrillation or the cardiac cycle; and stimulus generator that can deliver stimulation through at least two electrodes to stop atrial fibrillation. The method for treating atrial fibrillation has three possible modes: a first mode for detecting ongoing atrial fibrillation and stopping it; a second mode for detecting the cardiac cycle and delivering stimuli to the atrium after it has already begun to contract in order to suppress the onset of atrial fibrillation; and a third mode which applies pacing pulses to the atrium in a timed sequence to pace and contract the atrium faster than the native rate to preempt the initiation of atrial fibrillation.

Abstract: Methods for treatment of angina pectoris (e.g., control of angina pectoris and/or relief from its symptoms) include implantation of a miniature stimulator adjacent at least one tissue influencing angina pectoris. Stimulation sites include the thoracic cardiac nerves; sympathetic ganglia at T1-T4; stellate ganglia; fat pads of the sinoatrial node, atrioventricular node, and ventricles; sympathetic trunk at T1-T4 and branches thereof; thoracic spinal nerves and branches thereof, including intercostal nerves; and the subcostal nerves. Stimulation parameters are tailored for the stimulation site. In addition, the strength and/or duration of electrical stimulation required to produce a desired therapeutic effect may be determined based on a sensed response to and/or need for treatment. Thus, the stimulation parameters may be adjusted based on a sensed condition.

Abstract: Techniques are provided for detecting natural electrical coherence within the heart and for administering or adjusting therapy based upon whether natural electrical coherence is detected. In one example, an implantable cardioverter defibrillator (ICD), upon detecting atrial fibrillation, delays administering an atrial defibrillation pulse until a period of natural electrical coherence is detected between the left and the right atria of the heart. The ICD may further delay the pulse until the ventricles of the heart are refractory so as to help prevent triggering ventricular fibrillation. The pulses are administered at a time selected based upon the period of electrical coherence to reduce the amount of electrical energy required within the pulse to reliably defibrillate the heart. Other types of therapy besides defibrillation therapy such as anti-tachycardia pacing pulses may also be timed based upon detection periods of natural electrical coherence. Method and apparatus embodiments are described.

Abstract: Treatment of congestive heart failure (CHF) includes implantation of the discharge portion(s) of a catheter and, optionally, electrode(s) on a lead, near the tissue(s) to be stimulated. Stimulation pulses, i.e., drug infusion pulses and optional electrical pulses, are supplied by a stimulator implanted remotely, and through the catheter or lead, which is tunneled subcutaneously between the stimulator and stimulation site. Stimulation sites include the coronary arteries, the aorta, the left ventricle, the left atrium, and/or the pulmonary veins, among other locations. Disclosed treatments include drugs used for acute treatment of CHF, for chronic treatment of CHF, and drugs to reverse CHF.

Abstract: An implantable microminiature infusion device includes a reservoir for holding a therapeutic fluid or other substance and a driver, e.g., a pump, that delivers the therapeutic fluid or substance to a patient within whom the device is implanted. The device further includes at least two electrodes coupled to pulse generation circuitry, thereby allowing therapeutic electrical stimulation to also be delivered to the patient.

Abstract: An implantable microstimulator configured to be implanted beneath a patient's skin for tissue stimulation to prevent and/or treat various disorders, e.g., neurological disorders, uses a self-contained power source such as a primary battery, a rechargeable battery, or other energy sources. For the rechargeable battery, and other energy sources that may require a periodic or occasional replenishment, such recharging or replenishment is accomplished, for example, by inductive coupling with an external device. A suitable bidirectional telemetry link allows the microstimulator system to inform the patient or clinician regarding the status of the system, including the charge level of the power source, and stimulation parameter states. Processing circuitry within the microstimulator automatically controls the applied stimulation pulses to match a set of programmed stimulation parameters established for a particular patient.

Abstract: The stimulation device blanks T-waves from the atrial channel of an electrical cardiac signal by employing a T-wave blanking interval localized to the expected location and duration of the T-wave. To this end, the stimulation device determines the average interval between an R-wave and a T-wave in the patient in which the device is implanted and also determines the average duration of a T-wave within the patient. A T-wave blanking interval is initiated following the average R-T interval subsequent to detection of an R-wave and lasts for a period of time equal to the average T-wave duration. In this manner, highly localized T-wave blanking is achieved permitting P-waves or other atrial signals to be detected during remaining non-blanked portions of the atrial channel of the cardiac signal at least for the purposes of atrial rate detection. The relatively short T-wave blanking interval of the invention is particularly well suited for use in combipolar sensing systems.

Abstract: Communication between an implantable device(s), such as a neural stimulator, and an external remote device(s), e.g., a computer in a clinician's office, a computer in a patient's home, or a handheld patient remote control, is performed entirely via an RF link. In order to conserve power, the RF telemetry system of the implant is only activated periodically; with the period of activation being sufficiently short so as to allow a reasonably prompt response of the implant to a request for a communication session by the external device. In order to assure reliable communication, the RF information may be encoded, as appropriate, with error correction codes.

Abstract: An activity monitoring system measures the effectiveness of pain management using using data from motion or activity sensors attached to the patient's body to compute measures of exertion level of a patient. Increased levels of exertion are an indication of successful pain management. The patient's walking gait smoothness and walking gait stability are also graded as indicators of pain management effectiveness. The motion or activity sensors may be part of a temporary stimulation system used during percutaneous trials, part of a permanent implanted system, or an independent sensor package carried on the patient's body. The particular location and axes of the motion or activity sensors may be chosen based on the location of the pain being treated. The effectiveness of a particular pain management stimulation parameter set is based on the statistics accumulated over a period of time, for example one hour.

Abstract: A system and method for determining the onset and termination of cardiac events, such as the R-wave, the T-wave and the far-field signals sensed in the atria associated with the R-wave (FFR) and T-wave (FFT). The onset is defined as the time of the first sampled point of the cardiac signal whose magnitude exceeds a pre-defined threshold for the particular event. Once the onset of an event is positively determined, the cardiac signal is sampled at given intervals. The change in magnitude of these sampled points is determined. The termination of the event is identified through an algorithm that compares the difference in magnitude of these sampled points.

Abstract: A system and method for automatically adjusting the sensing parameters in an implantable cardiac stimulation device is described. The adjustment is based on the amplitudes and the onsets and ends of cardiac events, such as R-waves, T-waves, far-field R-waves, and/or far-field T-waves. Having determined the onset and termination of the cardiac events for a given number of cardiac cycles, particular variables that characterize these cardiac events can be averaged and stored in memory. Such variables include the peak amplitudes sampled during a cardiac event, the duration of the cardiac event, and the duration between cardiac events. Based on the averaged variables, the system automatically adjusts the sensing parameters, such as sensitivity, and blanking and refractory periods.

Abstract: An implantable cardiac stimulation device and method provides reliable sensing of cardiac events to support cardiac pacing or fibrillation detection. The device comprises a sensing circuit that senses the cardiac events in accordance with a plurality of threshold characterizing parameters. A parameter control adjusts the threshold parameters responsive to the rate of the sensed cardiac events in a manner which precludes positive feedback to prevent continued oversensing, undersensing, or noise sensing.

Abstract: An external transmitter circuit drives an implantable neural stimulator having an implanted coil from a primary coil driven by a power amplifier. For efficient power consumption, the transmitter output circuit (which includes the primary coil driven by the power amplifier inductively coupled with the implanted coil) operates as a tuned resonant circuit. When operating as a tuned resonant circuit, it is difficult to modulate the carrier signal with data having sharp rise and fall times without using a high power modulation amplifier. Sharp rise and fall times are needed in order to ensure reliable data transmission. To overcome this difficulty, the present invention includes an output switch that selectively inserts a resistor in the transmitter output coil circuit in order to de-tune the resonant circuit only during those times when data modulation is needed. Such de-tuning allows sharp rise and fall times in the data modulation without the need for using a high power modulation amplifier.

Abstract: Thrombolytic and/or anticoagulation therapy of the present invention includes implantation of the discharge portion(s) of a catheter and, optionally, one or more electrodes on a lead, adjacent tissue(s) to be stimulated. Stimulation pulses, i.e., drug infusion pulses and optional electrical pulses, are supplied by a stimulator implanted remotely, and through the catheter or lead, which is tunneled subcutaneously between the stimulator and stimulation site. Stimulation sites include the coronary arteries, coronary veins, cerebral arteries, other blood vessels, chambers of the heart, mesenteric vessels, deep vessels of the leg, and other locations. Disclosed treatments include drugs used for chronic treatment and/or prevention of thromboembolic disease, for acute treatment of thromboembolic disease, for acute treatment of thrombosis, and combinations of these.