Abstract: An implantable anti-tachyarrhythmia device which delivers anti-tachyarrhythmia therapies to a patient's heart in response to detection of tachyarrhythmias. The device defines first criteria indicating the presence of atrial tachycardia and second criteria indicating the presence of atrial fibrillation, and compares the time elapsed since the either the first or second criteria were initially met to a defined time duration. In response to the defined duration having passed and either of the first or second criteria being met, the device triggers delivery of an appropriate anti-tachyarrhythmia therapy. The timer is reset on detection of termination of atrial tachyarrhythmia, but not on failure of the first and second criteria to be met. The first and second criteria are defined such that they can not be concurrently met.

Abstract: In electrochemical cells for medical devices having anodes assemblies, an anode assembly includes a folded lithium element having a first and second section. The first and second sections are for receiving a current collector therebetween. A method of forming an anode arrangement includes a step of folding a lithium element having the first and second sections with a current collector positioned therebetween. Thereafter, a pressing step is performed in an oversized die.

Abstract: A peristaltic pumping mechanism is provided with a non-permeable peristaltic circuit comprising two strips of thin metal laser bonded at their edges to form a tube. In one embodiment, the non-permeable tubing takes the form of a continuous loop having input and output ports. In another embodiment, the tubing is open and generally U-shaped. In still another embodiment, a dual-tube circuit is provided, wherein a central, metal tube is disposed within an outer elastomeric tube having an inner diameter larger than the outer dimension of the metal tube. The elastomeric tube supports the metal tube only at the ends of the circuit, enabling the metal tube to “float” within the elastomeric tube.

Abstract: An apparatus and method for obtaining pressure data using a body implantable pressure sensor includes a measurement capacitor which is responsive to pressure changes of a body fluid. Non-constant, multiple current source charging of the measurement capacitor provides for a significant increase in sensitivity to conditions of pressure of a body fluid. Pressure data is obtained by charging the measurement capacitor at a first charge rate during a first charge period of an integration cycle and, during a second charge period of the integration cycle, charging the measurement capacitor at a second charge rate. The first charge rate is preferably greater than the second charge rate. The duration of the first and second charge periods may be varied. A signal indicative of a pressure change of a body fluid imparted to the measurement capacitor is produced by the pressure sensor. The signal may be a signal indicative of a change in a time of integration.

Abstract: An electrophysiology catheter (2) includes a handle (4) and a catheter shaft (6) having a flexible tip portion (22) with one or more electrodes (26, 28). A radial deflection wire (42) connects the tip portion to a first manipulator (10) at the handle to radially deflect the tip portion to a curved shape. A multifunction wire (60) extends from a second manipulator (11) at the handle to the tip portion. The second manipulator slides the multifunction wire longitudinally to position the distal end (64) of the multifunction wire along the multifunction lumen (38). The distal end of the multifunctional wire and the multifunction lumen are configured to provide interfering torquing surfaces (68, 70) so that when a third manipulator (12) rotates or torques the proximal end (62) of the multifunctional wire, the torquing force exerted between the interfering torquing surface causes lateral deflection of the radially curved tip portion.

Abstract: A stacked semiconductor device is formed with a first mounting substrate, e.g., a single metal layer die tape, having a first semiconductor die attached thereto and a second mounting substrate, e.g., a double metal layer die tape having a second semiconductor die attached thereto. Substantially columnar solder connections, each formed from two solder balls are used to stack the first mounting substrate and the second mounting substrate such that the second semiconductor die is positioned between the mounting substrates. For example, identical memory dice may be stacked in this manner or different types of die such as a processor die and a memory die may be stacked in this manner for use in implantable medical apparatus.

Abstract: A shape memory device includes a shape memory alloy member configured to have at least a portion of the shape memory alloy member be selectively activated. A heating device is coupled to the member and configured to provide heat to a selected section of the member and activate at least a portion of the selected section.

Abstract: A device for use in communication with an implantable medical device. The device is provided with a spatial diversity antenna array mounted to a housing and an RF transceiver operating at defined frequency, coupled to the antenna alray. The antenna array comprises two antennas spaced a fraction of the wavelength of the defined frequency from one another, each antenna including two antenna elements mounted to the housing and located oithogonal to one another. Selection of which of the antennas is employed is accomplished by an device controller, responsive to the quality of the signals received by the antennas.

Abstract: Downlink telemetry for an implantable medical device includes controlling downlink energy by generating a downlink strength signal representative of the strength of one or more downlink control bursts transmitted from an external communication device and received at the receiver of the implantable medical device. The peak amplitude of modulated downlink data bursts is controlled by adjusting the burst duration of the ramped envelope of such downlink data bursts as a function of the downlink strength signal.

Abstract: An AV search method and apparatus is taught with some variation. It allows a pacemaker to find the appropriate AV interval so as to avoid pacing in the ventricle when it is not necessary, even if there is intermittent AV conduction in the patient. Also, there is an adaptive PVARP method and apparatus that allows the PVARP and AV interval to be adjusted together automatically.

Abstract: An implantable anti-tachycardia pacemaker having the capability of switching from a first pacing regimen to a second pacing regimen, without waiting to determine whether the first pacing regimen actually is successful in terminating the tachycardia. The device first delivers a short series of pacing pulses at the defined parameters of the first pacing regimen and then interrupts delivery of pacing pulses and measures the return cycle of the subsequent spontaneous depolarization. The device then resumes delivery of the first pacing regimen for a second, greater number of pacing pulses and again measures the return cycle. In the event that no increase in the return cycle occurs following the delivery of the longer series of pacing pulses, the device terminates the pacing regimen presently underway, and initiates the next scheduled therapy. In the event that an increase in the return cycle is detected, the device may simply deliver the programmed number of pacing pulses defined for the first pacing regimen.

Abstract: Power consumption in medical and battery powered devices is reduced through the use and operation of a data monitor which measures, senses or detects signals, inputs or outputs in a medical device before they are input to a principal or main digital signal processor, controller or microprocessor. In response to detecting or measuring such a signal which meets certain amplitude, frequency and/or phase characteristics, the data monitor directs or controls clock or voltage supply circuits to increase or decrease clock frequency, or to increase or decrease the voltage provided to certain circuits within the medical device. The clock frequencies and/or voltages so employed are tailored to reduce the amount of power consumed by the medical device while preserving computational performance.

Abstract: A software programmable device means such as a microprocessor discriminates between evoked response signals and post-pace polarization signals sensed by an implantable medical device. The polarity of the positive or negative change in voltage in respect of time (or dv/dt) of the waveform incident on the lead electrodes is monitored during a short period of time immediately following a paced event. It has been discovered that the post-pace polarization signal exhibits a relatively constant polarity during the capture detect window, and that the evoked response signal may cause the polarity of post-pace polarization signal to reverse during the capture detect window . The sign of the post-pace polarization polarity, either positive or negative, is determined by the design of the specific output circuitry. The evoked response signal may reverse the polarity of the sensed signal in either case, from positive to negative or from negative to positive, during the time window of interest.

Abstract: A system and method for determining a patient's cardiac output in a non-invasive manner and transmitting cardiac output data to a remote host processor, a communications system, or a local output device is disclosed. A non-invasive cardiac monitoring approach utilizes an implantable medical device coupled to an oxygen sensor. The oxygen sensor provides venous oxygen saturation data to the implantable medical device. An oxygen consumption unit produces oxygen consumption data using air exhaled by a patient. A processing unit calculates a cardiac output result in real-time using the venous oxygen saturation data, the oxygen consumption data, and arterial oxygen saturation data assumed to be about 100% or acquired using a sensor external to the patient. The implantable medical device may transmit the venous oxygen saturation data to the processing unit using electromagnetic signals or acoustic signals.

Abstract: Power consumption in medical and battery powered devices is reduced through the use and operation of pipeline architecture in a digital signal processor, microcontroller or microprocessor by operating such devices at clock frequencies tailored to conserve power while preserving computational and executional performance. The digital signal processor, microcontroller or microprocessor can be operated at lower clock frequencies relative to those that would be required by one of such processors to complete the multiple functions within a predetermined time period but having no pipeline architecture. With reduced clock frequency, power consumption is reduced. Further, with reduced clock speed, supply voltages applied to such processors may also be reduced.

Abstract: An implantable dual transducer apparatus for use with an implantable medical device and control method are disclosed. The dual transducer assembly includes two physiologic sensors coupled to the medical device via a pair of lead conductors. Switching circuitry is controlled by the medical device to selectively activate and deactivate the two physiologic sensors by application of a supply voltage of an appropriate polarity. Each sensor of the dual transducer assembly is connected to the pair of lead conductors through a respective power switch. In response to the polarity of the supply voltage applied to the lead conductors, the power switches activate or deactivate their respective sensor in an alternating manner. Selective activation of one of the sensor while concurrently deactivating the other sensor of the dual transducer assembly provides for reduced power consumption and reliable communication of sensor data and other information transmitted over the pair of lead conductors.

Abstract: An electrochemical cell and electrode assembly are disclosed in which a separator having at least one thermally formed tab slot disposed therein is employed in conjunction with an alkali metal anode and a cathode assembly that are wound together in a unidirectional winding having substantially straight sides such that the winding will fit into a prismatic cell. The separator inhibits tearing or splitting of the material from which it is formed in the region of the tab slot. A tab connected to a current collector projects through the tab slot. The tab slots are formed by folding a separator material around a template, aligning the template with a slot guide, and applying heat to the separator material in the region of the slot(s).

Abstract: The present invention relates to a graphical display method and apparatus representing an electrogram signal received from at least one lead used in conjunction with an implantable medical device. The present invention provides a time-expanded waveform of a portion of a signal relating to a single heartbeat. Sensitivity threshold information is also graphically displayed on the waveform. The programmer assembly of the present invention comprises an analyzer for locating and marking desired characteristics of an electrogram signal received from at least one lead position within a passageway of a heart. The analyzer produces a marked electrogram signal. A processor receives the marked electrogram signal from the analyzer and recognizes the marked desired characteristics of the electrogram signal. A display, controlled by the processor, displays information representing a portion of the electrogram signal adjacent to the marked desired characteristics of the electrogram signal.

Abstract: Endocardial implantable cardiac leads are disclosed for applying electrical stimulation to and/or sensing electrical activity of the heart at one or more distal electrode positioned at a cardiac implantation site within a cardiac vessel adjacent to and at a desired orientation to the left ventricle or atrium of the heart. The distal electrode(s) is supported by a tubular electrode support having a diameter large enough to bear against the blood vessel wall and a support lumen that allows blood to flow through it. A retention stent extends proximally from a distal stent end fixed to the tubular electrode support to a proximal stent end. After advancement to the cardiac implantation site employing a lead delivery mechanism, the retention stent is expandable from a collapsed stent state in which the outer diameter of the retention stent is less than the inner diameter of the vessel to an expanded stent state.

Abstract: An introducer system for introducing a lead or catheter and a method of use. The introducer system includes an elongated introducer sheath which has a luer hub mounted to its proximal end through which a lead or catheter is introduced and a slitter for slitting the luer hub and the introducer sheath. The slittable luer hub takes the form of a conical or cylindrical member carrying a laterally extending tab adapted to engage internal threading on a female luer lock fitting and has a slittable portion angularly displaced from the tab. The slitter includes a blade, a handle carrying the blade, a mechanism for engaging the lead or catheter in the vicinity of the blade and a mechanism for engaging the lead or catheter proximal to the blade, configured such that the lead or catheter body when engaged by the slitter is angled proximal to the blade of the slitter.