Abstract: A visible and infrared light powered retinal implant is disclosed that is implanted into the subretinal space for electrically inducing formed vision in the eye. The retinal implant includes a stacked microphotodetector arrangement having an image sensing pixel layer and a voltage and current gain adjustment layer for providing variable voltage and current gain to the implant so as to obtain better low light implant performance than the prior art, and to compensate for high retinal stimulation thresholds present in some retinal diseases.

Abstract: An apparatus and a method for identifying fusion beats as part of an automatic capture routine in a cardiac stimulation device are disclosed. By requiring each post-pulse electrical response to be closely correlated with an expected morphology for either a capture condition or a loss-of-capture condition before classification of the post-pulse electrical response as either capture or loss-of-capture respectively, the present invention is able to identify fusion beats. In various embodiments, this fusion identification is performed using both template matching and assessment of particular detection features. Moreover, in one embodiment, a moving average and a standard deviation are maintained for each detection feature, thereby creating an automatically adjusting evoked response detection threshold.

Abstract: A method and apparatus for selection of one or more ventricular chambers to stimulate for ventricular resynchronization therapy. Intrinsic intracardia electrograms that include QRS complexes, are recorded from a left and right ventricle. A timing relationship between the intrinsic intracardia electrograms recorded from the left and right ventricle is then determined. In one embodiment, the timing relationship is determined using a delay between a left ventricular and a right ventricular sensed intrinsic ventricular depolarizations and a duration interval of one or more QRS complexes. In one embodiment, the duration of QRS complexes is determined from either intracardiac electrograms or from surface ECG recordings. One or more ventricular chambers in which to provide pacing pulses are then selected based on the timing relationship between intrinsic intracardia electrograms recorded from the right and left ventricle, and the duration of one or more QRS complexes.

Abstract: An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In a preferred embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Abstract: A blood pump may be adapted to sense the onset of left ventricular collapse by monitoring a pulsatility index, and may adjust the pump speed to maintain the index at a setpoint. The pulsatility index may be measured by the amount of difference between the maximum and the minimum volume of flow through the pump during a particular time period. The setpoint may be increased when the onset of ventricular collapse is detected, for example, when the pulsatility index falls suddenly. The setpoint may be decreased incrementally when the onset of ventricular collapse has not been detected for a period of time, such as for a particular period of time since the last detection of the onset of ventricular collapse.

Abstract: A method and system for operating a rate-adaptive pacemaker utilizing minute ventilation to measure exertion level. The method is applicable to heart failure patients who exhibit an oscillatory minute ventilation pattern.

Abstract: One embodiment of the present invention provides an implantable cardioverter-defibrillator for subcutaneous positioning over a patient's ribcage, the implantable cardioverter-defibrillator includes a housing having a first end and a second end; a first electrode disposed upon the first end of the housing; a second electrode disposed upon the second end of the housing; an electrical circuit located within the housing, wherein the electrical circuit is electrically coupled to the first electrode and the second electrode; and a lead electrode electrically coupled to the electrical circuit located within the housing.

Abstract: An implantable cardiac stimulation device delivers successive defibrillation waveforms using alternating counter electrodes selected from a case electrode and an electrode located on a coronary sinus lead. The case electrode and coronary sinus electrode may be selected individually in an alternating fashion such that the defibrillation pathway alternates between two single pathways during a defibrillation regimen. The case electrode and the coronary sinus electrode may also be used simultaneously in parallel to create a dual pathway. Defibrillation waveforms may then be delivered in a cyclical fashion between the individual counter electrodes and the combined counter electrodes such that alternation between single pathways and a dual pathway is achieved.

Abstract: The present invention comprises a method for stimulating angiogenesis. The method comprises the steps of electrically stimulating muscle below the threshold for muscle contraction.

Abstract: A fully implantable cochlear prosthesis includes (1) an implantable hermetically sealed case wherein electronic circuitry, including a battery and an implantable microphone, are housed, (2) an active electrode array that provides a programmable number of electrode contacts through which stimulation current may be selectively delivered to surrounding tissue, preferably through the use of appropriate stimulation groups, and (3) a connector that allows the active electrode array to be detachably connected with the electronic circuitry within the sealed case. The active electrode array provides a large number of both medial and lateral contacts, any one of which may be selected to apply a stimulus pulse through active switching elements included within the array. The active switching elements included within the array operate at a very low compliance voltage, thereby reducing power consumption.

Abstract: A method for operating a cardiac rhythm management device in which a clinical state vector is computed as a combination of a plurality of parameters related to a patient's heart failure status and compared to a previously computed clinical state vector to determine a clinical trajectory indicative of changes in the patient's heart failure status. Such detected changes in status can be used both as a clinical tool to evaluate treatment and to automatically adjust the operation of the device.

Abstract: A computer software program is described that maps the electrical activity of a patient's heart. The software program utilizes inputs from electrodes contained within a heart chamber. Inputs from the electrodes cause the program to calculate the heart chamber volume, and then to determine the position of the electrodes within the heart chamber. The program then utilizes inputs from the electrodes to calculate the three-dimensional volumetric electrical field distribution of said heart chamber. This calculation is accomplished using a spherical harmonic series expression. Finally, the computer program displays the electrical field distribution of the heart chamber.

Abstract: A circuit for delivering a back-up stimulation voltage in a cycle to cycle capture test for an active implantable medical device such as a pacemaker, defibrillator and/or cardiovertor or a multisite device having an enhanced circuit for delivering back-up stimulation pulses.

Abstract: Optimization of evoked response detection in an automatic capture detection system employed by an implantable cardiac stimulation device is presented. Patient state information is used to determine the appropriate settings of variables that are associated with the evoked response signal detection algorithm. The variables used by the evoked response signal detection algorithm are first established for the patient in a variety of positions. During operation of the implantable cardiac stimulation device, the patient state is monitored and the variables used by the evoked response signal detection algorithm are adjusted accordingly.

Abstract: An implantable lead for electrical stimulation of the body includes an elongated multi-lumen proximal tube composed of a first material having a first lumen for freely receiving a guidewire therethrough, a cable conductor extending between proximal and distal ends and received in a second lumen of the proximal tube, an elongated distal tube composed of a second material extending between proximal and distal ends having at least one lumen therein, a distal tip electrode attached to the distal end of the distal tube, a coil conductor received in the lumen of the distal tube extending between the proximal end thereof and the distal end thereof and being joined at the distal end to the distal tip electrode, and a joint assembly for electrically and mechanically connecting the distal end of the cable conductor to the proximal end of the coil conductor.

Abstract: An implantable stimulation lead is disclosed for placement in the coronary sinus region and its associated coronary vessels overlying the left side of a patient's heart. The lead comprises at least one proximal connector; at least one tissue stimulation electrode; at least one conductor coupled between the at least one proximal connector and the at least one stimulation electrode; and a lead body including a housing of insulating material enclosing the at least one conductor, the lead body having a relatively flexible distal portion of, for example, silicone rubber, having a length corresponding to the coronary sinus region of the heart, and a stiffer proximal portion of, for example, polyurethane. A robust transition joint comprising telescoped sections of the distal and proximal portions of the lead body couples the two portions of the lead body. Also provided is a versatile lead delivery system including a stylet stop disposed within the distal portion of the lead body.

Abstract: An automatic external defibrillator including: a sensor for detecting when a rescuer is delivering a CPR chest compression to the patient; electrodes for application to the thorax of the patient for delivering a defibrillation shock to the patient and for detecting an ECG signal; defibrillation circuitry for delivering a defibrillation shock to the electrodes; and a processor and associated memory for executing software that controls operation of the defibrillator. The software provides: ECG analysis for analyzing the ECG signal to determine if the cardiac rhythm is shockable; CPR detection for analyzing the output of the sensor to determine when a CPR chest compression has been delivered, and integration of the ECG analysis and CPR detection so that the determination of whether the cardiac rhythm is shockable is based only on time periods of the ECG signal during which there has not been a CPR chest compression delivered.

Abstract: High side driver circuitry for a defibrillator circuit employs respective capacitors connected to respective gates of silicon controlled rectifiers serving as high side switches. Applying a voltage pulse to a selected capacitor turns on the associated SCR. Positive turn-on of the high side SCRs is insured by inserting a constant current source into the low side activation current path at start-up.

Abstract: A method for extracting and evaluating features from cardiac acoustic signals includes the steps of obtaining a cardiac acoustic signal, extracting physiologically significant features from the cardiac acoustic signal using a neural network, analyzing the cardiac acoustic signal with a wavelist decomposition to extract time-frequency information, and identifying basic heart sounds using neutral networks applied to the extracted time-frequency information. A method for determining a status of heart murmurs includes the steps of obtaining a cardiac acoustic signal, detecting a murmur, if any, from the cardiac acoustic signal, and determining whether the murmur is one of functional and pathological based upon expert rules.

Abstract: A power supply for an implantable cardioverter-defibrillator for subcutaneous positioning between the third rib and the twelfth rib and using a lead system that does not directly contact a patient's heart or reside in the intrathoracic blood vessels and for providing anti-tachycardia pacing energy to the heart, comprising a capacitor subsystem for storing the anti-tachycardia pacing energy for delivery to the patient's heart; and a battery subsystem electrically coupled to the capacitor subsystem for providing the anti-tachycardia pacing energy to the capacitor subsystem.