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: An implantable medical device includes a sensor and a T-wave analyzer. The sensor is implantable within the body of a patient to sense electrical cardiac activity and provide an indication of T-wave alternans within the heart of the patient. The T-wave analyzer is responsive to the sensor, and evaluates cardiac risk based on comparison of the indication of T-wave alternans to a predetermined criterion. The T-wave analyzer may form part of a microprocessor, a digital signal processor, or combination of both. The device may include a pacing generator that applies increased rate pacing stimuli to the heart to facilitate sensing of the T-wave alternans by the sensor. The device also may incorporate a memory that stores the T-wave alternans indication provided by the sensor, e.g., over a number of heartbeats. In addition, the device may be equipped to provide an alert to the patient or a physician in the event the processor generates the indication of cardiac risk.

Abstract: An implantable endocardial lead for use with a cardiac stimulation device includes an electrically active housing including a tubular end region extending to a terminal rim at the distal end of the lead and an electrical conductor within the lead extending between proximal and distal ends. An active fixation electrode within and spaced from the electrically active housing includes an electrically active helix coaxial with the endocardial lead coupled to the distal end of the electrical conductor and movable between a retracted position fully within the housing and an extended position advanced beyond the terminal rim of the housing for effecting penetration into the myocardial tissue. A guide system located proximally of the active fixation electrode serves to rotate the electrically active helix about the longitudinal axis as the helix is moved between the retracted and extended positions.

Abstract: The invention presents techniques for processing an atrial electrogram. An atrial electrogram senses atrial events, but may also sense a ventricular event, causing a far field R-wave to be present in the atrial electrogram signal. A far field R-wave is an undesired artifact. The invention provides techniques for estimating the far field R-wave and subtracting the far field R-wave from the atrial electrogram signal.

Abstract: A cardiac stimulation device and method perform a diastolic function test during which an amplitude-based feature of an evoked response is determined for a number of AV or PV delay settings. Stimulation operating parameters may be adjusted in response to a detected change in diastolic function. The diastolic function test may be repeated periodically with results stored in memory for later downloading to an external device allowing a physician to monitor the diastolic response to a selected treatment.

Abstract: A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.

Abstract: An improved antenna for use with an implantable microdevice, such as a microstimulator or microsensor, comprises a loop antenna on the case of the microdevice. The antenna receives data transmitted from an external device, and transmits data to an external device. Such a loop antenna may be formed from two cylindrical sections separated by an insulating material on the case of the microdevice, or by separating a metal cylinder into two parallel semi-cylinders separated by an insulating material. A tuning circuit comprising capacitors and/or varactors is used to obtain resonance in the loop antenna, thus creating a sufficiently large effective antenna aperture. In a preferred embodiment, the electrodes of the microdevice are modified to both perform their primary task of tissue stimulation and to perform a secondary task as the radiating elements of a loop antenna.

Abstract: A multi-sensor system for controlling an implantable heart stimulator, and an implantable heart stimulator containing such a multi-sensor system, have a piezoelectric pressure sensor adapted for placement in the blood stream of a subject, the piezoelectric pressure sensor having at least one electrode that is adapted for electrical contact with the blood stream, and an oxygen pressure sensor having a measurement electrode formed by the (at least one) electrode of the piezoelectric pressure sensor.

Abstract: One embodiment of the present invention provides an implantable cardioverter-defibrillator for subcutaneous positioning between the third rib and the twelfth rib within a patient, the implantable cardioverter-defibrillator including a housing, wherein at least a portion of the housing is curved; an electrical circuit; and an electrically conductive surface located on a portion of the housing, wherein the electrically conductive surface is coupled to the electrical circuit.

Abstract: A laminated multi-electrode biocompatible implant, comprising a first layer of flexible, biocompatible dielectric material having a first, exposed surface. A second layer of flexible biocompatible dielectric material, is adhered to the first layer. Further, a third layer of flexible biocompatible dielectric material is adhered to the second layer. Additionally, a first conductive trace is interposed between the first layer and the second layer and a second conductive trace interposed between said second layer and said third layer. Finally, a first conductor, which breaches said first layer, conductively connects the first conductive trace to the exposed surface of the first layer, thereby forming a first electrode and a second conductor, which breaches the first layer and the second layer, conductively connects the second conductive trace to the exposed surface of the first layer, thereby forming a second electrode.

Abstract: Electrode assemblies are provided, in which a pair of electrodes is joined by a central member. In some implementations, the electrode assemblies are foldable, and are configured to facilitate correct placement on a patient's chest. Some electrode assemblies include a separable electrode, allowing the electrode assembly to be fitted to patients having particularly large chests.

Abstract: A method for indirectly stimulating a vagus nerve of a patient includes the steps of positioning one or more electrodes in the vicinity of the vagus nerve and then actuating the electrode(s) to create an electrical field for stimulating the vagus nerve. Disclosed embodiments include positioning one or more electrodes in the esophagus, trachea, or jugular vein, on the neck of the patient, and combinations thereof.

Abstract: In one embodiment, a method is characterized by measuring a patient parameter associated with a human body; in response to the patient parameter, retrieving a maximum expected device parameter; and setting a limit on an energy source such that during defibrillation of the patient a defibrillation parameter associated with the maximum expected device parameter is within a defined tolerance. In another embodiment, a method is characterized by specifying at least one device parameter limit of a defibrillation unit; and in response to the at least one specified device parameter, determining a prediction confidence level at which the device parameter limit is exceeded for one or more values of a patient parameter.

Abstract: An improved method and device for performing anti-tachycardia pacing (ATP) to convert a ventricular tachycardia (VT) to normal sinus rhythm. Pacing/sensing electrodes are implanted in or on the left and right ventricles of a patient's heart. After a VT is detected a determination is made based on the shape of the electrogram signal of the VT. One of a plurality of time offsets for pacing pulses of the left and right ventricles is selected based on the signal shape and ATP is performed by pacing both the left and right ventricles with the time offset between pulses in the respective ventricles.

Abstract: Upon interrogating a pacemaker, implantable cardioverter defibrillator or other implantable cardiac stimulation device, an external programmer accesses previously-stored physician comments maintained within the implanted device. The programmer disables any reprogramming of the implanted device until the physician comments have been displayed via the programmer for review by the physician or other medical professional seeking to reprogram the implanted device. In this manner, critical information pertaining to a previous programming session is presented to the physician before any additional reprogramming is permitted so as to ensure that the critical information is reviewed. In one example described herein, physician comments are designated as being either general or parameter-specific. General comments are displayed for review before any reprogramming is permitted. Parameter-specific comments are displayed for review only if the physician seeks to reprogram particular parameters associated therewith.

Abstract: An implantable device having enhanced capabilities for monitoring a patient's heart rate and respiration trends over extended periods of time is disclosed. The information collected by the implantable device may be stored and telemetered to an associated external device such as a device programmer for display and analysis. Heart rates are measured by measuring the time intervals between sensed depolarizations of a chamber of the patient's heart and preceding sensed depolarizations or delivered pacing pulses. Intervals may be measured in the ventricle and/or atrium of the patient's heart. According to another aspect of the invention, an implanted impedance sensor is employed to monitor minute ventilation. The heart rate and minute ventilation data is used to develop long-term trend data used for diagnostic purposes. In one embodiment of the invention, heart interval and minute ventilation measurements are taken only during defined time periods of the night and/or day when the patient is at rest.

Abstract: A fetal heart monitoring system preferably comprising a backing plate having a generally concave front surface and a generally convex back surface, and at least one sensor element attached to the concave front surface for acquiring acoustic fetal heart signals produced by a fetus within a body. The sensor element has a shape that conforms to the generally concave back surface of the backing plate. In one embodiment, the at least one sensor element comprises an inner sensor, and a plurality of outer sensors surrounding the inner sensor. The fetal heart monitoring system can further comprise a web belt, and a web belt guide movably attached to the web belt. The web belt guide being is to the convex back surface of the backing plate.

Abstract: The gate means 73 extracts the partial impedance pulse wave SMIMP(P) from the thorax impedance pulse wave SMIMP detected by the thorax impedance pulse wave detector 64. This is done over an intake period defined as a period starting from a first time T1 after the time when the R wave of the induced electro-cardiac wave is detected to the time when a rising edge of the photoelectric pulse wave SM2 is detected. Then, the heartbeat synchronous information determining means 74 selects a rising edge of the partial impedance pulse wave SMIMP(P) that periodically appears as heartbeat synchronous information IH. Thus, it is possible to accurately determine the heartbeat synchronous information IH. Additionally, since the photoelectric pulse wave SM2 that is detected by the photoelectric pulse wave sensor 40 is largely free of noise it is possible to accurately determine the end of the period for reading the thorax impedance pulse wave SMIMP.

Abstract: The invention relates to an electronic wrist-worn device, such as a heart rate monitor, a sportsman's watch or a diving computer, and its control method. The outside of the casing of the device comprises a bottom surface to be placed against the wrist, a top surface (304), and a side surface (308) between the bottom surface and the top surface (304). On the top surface (304) of the casing there is provided a first display (306) connected to the control electronics. On the side surface (308) of the casing there is provided a second display (400, 402, 404; 406) connected to the control electronics. The best viewing angle of the first display (306) and the best viewing angle of the second display (400, 402, 404; 406) are at an angle of 60 to 120 degrees with respect to each other.

Abstract: An elongated coronary vein lead having a variable stiffness lead body and most preferably adapted to be advanced into a selected coronary vein for delivering a pacing or defibrillation signal to a predetermined region of a patient's heart, such as the left ventricle is disclosed. A method of pacing and/or defibrillating a patient's heart using the lead is also described. The method of pacing or defibrillating the heart includes advancing the coronary vein lead through both the coronary sinus and into a selected coronary vein of a patient's heart, connecting the lead to an electrical pacing source and applying electrical stimulation to a particular chamber of the patient's heart via the implanted lead. The lead includes a variable stiffness lead body that enhances the ability of the lead to be retained in a coronary vein after the lead has been implanted therein.