Abstract: Methods for delivering first and second fluid compositions to a target location of a subject include delivering the first composition from reservoir of an implantable infusion pump and delivering the second composition through a catheter access port of the implantable infusion device. The access port and reservoir are fluidly coupled to a catheter having a delivery region implanted in the target region. The methods more fully realize the therapeutic potential of infusion devices having both an access port and a reservoir. Strategic use of different agents that compliment the function of each other delivered via either the access port or the reservoir can result in enhanced therapeutic potential.

Abstract: An improved implantable sensor system is disclosed that includes an array of sensors. Each of the sensors is associated with a protective member that prevents the sensor from interacting with the surrounding environment. At a selected time, the protective member may be disabled, thereby allowing the sensor to begin sensing signals within a living body. In one embodiment, the protective member is formed of a conductive material that can oxidize, is biocompatible, bio-absorbable, and that may be dissolved in solution such as blood upon application of an electric potential. In another embodiment, the protective member is formed of a dissolvable member that dissolves within the body over a predetermined time period.

Abstract: An implantable medical device having a dual cell power source powering a high-power output circuit and a low-power control circuit. The power source includes a first, high-rate cell and a second, lower-rate cell having a rate capability less than a rate capability of the first, high-rate cell. The first and second cells are electrically connected to the output circuit and control circuit by circuitry. In one embodiment, the circuitry connects the first and second cells in parallel to the output circuit and the control circuit, and includes a switching circuit for selectively uncoupling the first, high-rate cell from the control circuit during a transient high power pulse. In another embodiment, the first and second cells are formed within a single case and are connected in parallel to the output circuit and the control circuit.

Abstract: An implantable medical device having a dual cell power source powering a high-power output circuit and a low-power control circuit. The power source includes a first, high-rate cell and a second, lower-rate cell having a rate capability less than a rate capability of the first, high-rate cell. The first and second cells are electrically connected to the output circuit and control circuit by circuitry. In one embodiment, the circuitry connects the first and second cells in parallel to the output circuit and the control circuit, and includes a switching circuit for selectively uncoupling the first, high-rate cell from the control circuit during a transient high power pulse. In another embodiment, the first and second cells are formed within a single case and are connected in parallel to the output circuit and the control circuit.

Abstract: An improved implantable sensor system is disclosed that includes an array of sensors. Each of the sensors is associated with a protective member that prevents the sensor from interacting with the surrounding environment. At a selected time, the protective member may be disabled, thereby allowing the sensor to begin sensing signals within a living body. In one embodiment, the protective member is formed of a conductive material that can oxidize, is biocompatible, bio-absorbable, and that may be dissolved in solution such as blood upon application of an electric potential. In another embodiment, the protective member is formed of a dissolvable member that dissolves within the body over a predetermined time period.

Abstract: A system and method is provided to view an anatomical structure such as a blood vessel in high contrast with its surrounding tissue. The system and method may be used to produce an image of an anatomical structure using reflected electromagnetic radiation singularly scattered from target tissue. The system and method may also provide same-side illumination and detection of reflected electromagnetic radiation in a convenient integral imaging device. The system and method may also provide helmet mounted imaging technology in a single integral helmet which allows the wearer to view an anatomical structure located within a patient such that the image is continuously oriented according to the orientation of the helmet wearer's head. The system and method may also be used in the performance of venipuncture. The system and method may provide for improved contrast between any anatomical structure and its surrounding tissue for use in any imaging system.

Abstract: A lead and a lead system for dispersion of a cardioversion/defibrillation electrode formed of one or more small diameter defibrillation electrodes in a heart chamber and for attaching a pace/sense electrode in contact with the heart. The small diameter defibrillation electrode or electrodes extend distally from the distal end of the lead body. If multiple electrodes are employed, they are preferably biased to spread apart when unrestrained and have a cross-section size small enough to be inserted into interstices of trabeculae in the ventricular chamber. The distal ends of the defibrillation electrodes may be free of attachment to the lead body or may be attached by a weak bond to the distal portion of the lead.

Abstract: An alternative mechanism in an implantable device for meeting the physician's need for a stored electrogram and/or other stored physiologic signal associated with a detected arrhythmic or other physiological event without the undesirable current drain associated with continuous operation of a sense amplifier and a looping memory. The device regularly but intermittently activates a sense amplifier or other sensor and associated memory circuitry, independent of detection of arrhythmias. The device may temporarily store only a single record, replacing it with new records as they are stored, or may store multiple records, replacing the oldest stored record with the newest stored record. On detection of an arrhythmia or other defined physiological event, the device may simply transfer the one or more temporarily stored electrogram strips to permanent storage, for later use by the physician in diagnosing the condition of the patient prior to detection of the event.

Abstract: A lead and a lead system for dispersion of a cardioversion/defibrillation electrode formed of one or more small diameter defibrillation electrodes in a heart chamber and for attaching a pace/sense electrode in contact with the heart. The small diameter defibrillation electrode or electrodes extend distally from the distal end of the lead body. If multiple electrodes are employed, they are preferably biased to spread apart when unrestrained and have a cross-section size small enough to be inserted into interstices of trabeculae in the ventricular chamber. The distal ends of the defibrillation electrodes may be free of attachment to the lead body or may be attached by a weak bond to the distal portion of the lead.

Abstract: A lead and a lead system for dispersion of a cardioversion/defibrillation electrode formed of one or more small diameter defibrillation electrodes in a heart chamber and for attaching a pace/sense electrode in contact with the heart. The small diameter defibrillation electrode or electrodes extend distally from the distal end of the lead body. If multiple electrodes are employed, they are preferably biased to spread apart when unrestrained and have a cross-section size small enough to be inserted into interstices of trabeculae in the ventricular chamber. The distal ends of the defibrillation electrodes may be free of attachment to the lead body or may be attached by a weak bond to the distal portion of the lead.

Abstract: An adaptive, performance-optimizing communication system for communicating with an implanted medical device in which signals are transmitted and received in accordance with predetermined, interrelated operational parameters, such as transmission rate, transmitter power, and the like. Various aspects of system performance, including bit error rate in received signals, the strength of received signals, the signal-to-noise ratio of received signals, the presence of local RF noise and non-telemetry related RF signals, and the like, are dynamically monitored by the communication system, to determine whether predetermined system performance goals are being met. If it is determined that one or more system performance goals are not being met, one or more operational parameters may be automatically adjusted so that desired performance can be achieved.

Abstract: A method of improving the breakdown strength of polymer multi-layer (PML) capacitors is provided. The method comprises removing metal, specifically, aluminum, from the cut edge. This is done by either etching back the metal electrode layers in either basic or acidic solution or by anodizing the metal to cover that portion of the metal at the edge with an oxide. Removing the metal from the cut edge increases the breakdown strength of the PML capacitors by a factor of two or more.

Abstract: An adaptive, performance-optimizing communication system for communicating with an implanted medical device in which signals are transmitted and received in accordance with predetermined, interrelated operational parameters, such as transmission rate, transmitter power, and the like. Various aspects of system performance, including bit error rate in received signals, the strength of received signals, the signal-to-noise ratio of received signals, the presence of local RF noise and non-telemetry related RF signals, and the like, are dynamically monitored by the communication system, to determine whether predetermined system performance goals are being met. If it is determined that one or more system performance goals are not being met, one or more operational parameters may be automatically adjusted so that desired performance can be achieved.

Abstract: A power supply arrangement for a battery-powered device includes a high energy density capacitor which is selectively coupled to the device's battery. In one embodiment, the device includes a first circuit which requires a continuous operational power supply voltage to be applied to its power supply input, and further includes a second circuit periodically operates in a peak phase in which it places a high demand upon the device's battery. During normal operation of the device, the first circuit's power supply input and the high energy density capacitor are coupled to the battery so that operational power for the first circuit is provided directly from the battery, and the high energy density capacitor is charged by said battery.

Abstract: An implantable antitachyarrhythmia device having the capability of detecting multiple tachyarrhythmias, such as ventricular tachycardia and ventricular fibrillation and capable of delivering multiple therapies, such as antitachycardia pacing, cardioversion and defibrillation. In order to assist the physician in understanding the progress of the device toward detecting a tachyarrhythmia and to better understand the operation of the therapy provided by the device, the device transmits information related to these functions on a beat by beat basis, as a supplement to marker signals associated with paced and sensed heart events. The information telemetry regarding detection allows the physician to determine how the particular R--R interval preceding the telemetry has effected the internal counts or other diagnostic parameters required to accomplish tachyarrhythmia detection.

Abstract: An apparatus for detecting, identifying and treating tachyarrhythmias. Tachyarrhythmias are detected and identified by the use of overlapping ranges of intervals. Provisional identification of tachyarrhythmia is accomplished by measuring and tracking intervals within two overlapping or adjacent interval ranges. Further classification and identification of tachyarrhythmias is accomplished by determining the relative numbers of intervals within a preceding series falling within a third interval range, overlapping one or both of the other interval ranges. In response to identification of the tachyarrhythmia, an appropriate therapy is selected and delivered.

Abstract: A combined pacing and cardioversion lead system with internal electrical switching components for unipolar or bipolar sensing of electrograms, pacing at normal pacing voltages and cardioversion or defibrillation. In bipolar embodiments, an indifferent electrode, closely spaced to a sensing and pacing electrode, is coupled in common through the integral switching circuitry to a large surface area cardioversion electrode. In these embodiments, pacing and sensing is accomplished through a pair of conductors extending through the lead system to the closely spaced active and indifferent electrode pair. When cardioversion energy is applied to the indifferent electrode, the cardioversion energy is also directed to the cardioversion electrode through operation of the switching circuitry in response to the magnitude of the applied cardioversion pulse. In unipolar embodiments, a distal sensing and pacing electrode is coupled through integral switching circuitry to a large surface area cardioversion electrode.

Abstract: An implantable cardioverter/defibrillator capable of detecting fibrillation and other tachyarrhythmias and of generating high energy cardioversion and defibrillation pulses. The device delivers cardioversion pulses and defibrillation pulses synchronized to heart rhythm, wherever possible. Delivery of cardioversion pulses requires verification of the continuing presence of a tachyarrhythmia, following charge up of the output capacitor in the pulse generator. In the event that cardioversion therapy is aborted, the charge on the capacitor is retained until subsequent detection of termination of the tachyarrthythmia. Defibrillation pulses are delivered synchronized to heart rhythm, wherever possible, but are delivered asynchronously if synchronization is not possible. Following delivery of a cardioversion or defibrillation pulse, the charge remaining on the capacitor is retained until detection of tachyarrhythmia or fibrillation termination, respectively.

Abstract: An implantable cardioverter having circuitry for generating high energy cardioversion and defibrillation pulses. The output circuitry is so configured that it may provide simultaneous pulse, multiple electrode; sequential pulse, multiple electrode; or single pulse, two electrode defibrillation and/or cardioversion pulse regimens. The output circuitry is configured to allow delivery of energy sequentially from two capacitor banks during sequential pulse regimens and to deliver the energy stored in both capacitor banks simultaneously during simultaneous pulse, multiple electrode and single pulse, two electrode defibrillation pulse regimens.

Abstract: An implantable cardiac pacemaker and/or cardioverter/defibrillator employing an R-wave detector which atuomatically adjusts its sensing threshold in response to R-wave amplitude. The R-wave detector produces an output which is used to indicate the occurrence of ventricular contractions, and is used to reset the timing of the pacemaker and to indicate the occurrence of ventricular contractions for purposes of activating the associated cardioverter/defibrillator. Adjustment of the threshold is disable for a predetermined period following the delivery of each pacing pulse such that in the presence of continuous pacing for a predetermined period of time, the sensing threshold is returned to a desired, lower threshold level, allowing for detection of lower level R-waves, which may be indicative of tachyarrhythmia or fibrillation.