Abstract: There is provided a pacemaker system having the capability of providing therapy for preventing conditions likely to lead to myocardial infarction or ventricular arrhythmia during patient morning time. Specifically, a therapy is initiated before calculated patient awakening time, for raising pacing rate slowly so as to shorten QT interval to an acceptable level relative to rate at the time of patient awakening, and specifically a level that achieves satisfactory diastolic filling time. The pre-awakening therapy pacing routine is designed to overcome normal QT prolongation which occurs during sleep state, and which is delayed after patient awakening. In the event that criteria for an acceptable diastolic filling time are not met at or after patient awakening, the pacemaker takes steps to control rate, such as ceasing synchronous pacing and limiting automatic rate response.

Abstract: An electrochemical cell and electrode assembly in which an alkali metal anode and a cathode assembly are wound together in a unidirectional winding having substantially straight sides such that the winding will fit into a prismatic cell. The anode and cathode are arranged in the winding to provide for even utilization of reactive material during cell discharge by placing cathode and anode material in close proximity throughout the electrode assembly in the proportions in which they are utilized. The winding also contributes to even utilization of reactive material by employing multiple tabs on the cathode assembly to ensure that cathode material is evenly utilized throughout the electrode assembly during cell discharge and also so that connections to the tabs are readily made.

Abstract: An introducer system for a lead, catheter, probe or the like, employing a dilator and introducer sheath assembly for dilating a body vessel in preparation for introducing the lead, etc., through the lumen of the introducer sheath that provides for the injection of radiopaque contrast media to observe the cause of an impediment to advancement of the assembly into the vessel lumen. The dilator is formed of an elongated dilator body having a guide wire lumen therein for receiving and being advanced over the guide wire and a hub assembly at the proximal end of the guide wire body. An injection lumen is also formed in the dilator body isolated from the guide wire lumen and in fluid communication with a side port formed in the hub assembly and an injection port formed in the distal end of the dilator body. Preferably, the injection port is formed in a tapered distal end portion of the dilator.

Abstract: Power consumption in medical and battery powered devices is reduced through the use and operation of multiple digital signal processing systems and through the application of different supply voltages to analog and digital circuits, respectively. Each processor of the multiple systems performs at least one particular function in a predetermined time period. The multiple digital signal processors of such systems 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 the predetermined time period. With reduced clock frequency, power consumption is reduced. Further, with reduced clock speed, supply voltages applied to such digital signal processors may also be reduced. A source applies a first fixed supply voltage to the digital circuits of the medical or battery powered device and a voltage generation circuit (e.g.

Abstract: A pacing system and method for providing multiple chamber pacing of a patient's heart, and in particular, pacing programmed for treatment of various forms of heart failure. The system utilizes impedance sensing for determining optimum pacing parameters, e.g., for pacing the left ventricle so that left heart output is maximized. The impedance sensing also is used for determination of arrhythmias or progression of heart failure. Impedance sensing is provided for between selected pairs of the four chambers, to enable optimizing of information for control and diagnosis. In a preferred embodiment, impedance measurements are obtained for determining the timing of right heart valve closure or right ventricular contractions, and the timing of delivery of left ventricular pace pulses is adjusted so as to optimally synchronize left ventricular pacing with the right ventricular contractions.

Abstract: A receiving and filtering circuit includes an antenna, a demodulator circuit coupled to the antenna, and a digital median filter that removes high frequency content of a demodulated digital information signal to produce a filtered digital information signal corresponding to an analog data signal transmitted by a body implantable medical apparatus. The digital filter may include a multiple stage delay line coupled to a multiple tap selection device, a plurality of delay blocks coupled to a register, or a multiple stage delay line coupled to a voting unit. The voting unit produces a first binary output in response to a majority of delay line stages storing a first value, and produces a second binary output in response to a majority of delay line stages storing a second value. The digital filter may also comprise a digital signal processor. The digital filter may include a first filter block and a second filter block. The second filter block may be selectively activated or bypassed.

Abstract: A medical device system such as a pacemaker system is provided wherein pressure signals representative of a patient's cardiac movements are transmitted through a pacing lead to the pacemaker, where they are sensed and utilized for control of pacemaker operation. In a preferred embodiment, the invention utilizes a standard pacing lead, which may already be in place within the patient, the lead having a lumen through which relative pressure signals are transmitted from the patient's heart to the proximal end of the lead. The proximal end of the lead is connected to a pressure sensor, mounted either in the pacemaker header portion or within the hermetically sealed pacemaker can. The sensor signals are coupled to appropriate processing circuitry and are used for control of one or more pacing parameters, such as pacing rate.

Abstract: A pacing system and method for providing multiple chamber pacing of a patient's heart, and in particular, pacing programmed for treatment of various forms of heart failure. The system utilizes impedance sensing for determining optimum pacing parameters, e.g., for pacing the left ventricle so that left heart output is maximized. The impedance sensing also is used for determination of arrhythmias or progression of heart failure. Impedance sensing is provided for between selected pairs of the four chambers, to enable optimizing of information for control and diagnosis. In a preferred embodiment impedance measurements are obtained for determining the timing of right heart valve closure or right ventricular contractions, and the timing of delivery of left ventricular pace pulses is adjusted so as to optimally synchronize left ventricular pacing with the right ventricular contractions.

Abstract: An accelerometer device which can be mounted on a substrate, e.g., a circuit board enclosed in a medical device, includes an accelerometer sensing element having an axis of sensitivity and further includes first and second multilayer end caps. The substrate generally defines a mounting plane. The accelerometer sensing element includes a device body having a longitudinal axis extending between generally parallel first and second ends thereof and further includes a principal surface extending between the first and second ends of the device body parallel to the longitudinal axis. The axis of sensitivity of the sensing element is generally perpendicular to a plane defined by the principal surface. Further, the accelerometer sensing element includes conductive pad regions on each of the first and second ends of the device body.

Abstract: A pacing system and method for providing multiple chamber pacing of a patient's heart, and in particular, pacing programmed for treatment of various forms of heart failure. The system utilizes impedance sensing for determining optimum pacing parameters, e.g., for pacing the left ventricle so that left heart output is maximized. The impedance sensing also is used for determination of arrhythmias or progression of heart failure. Impedance sensing is provided for between selected pairs of the four chambers, to enable optimizing of information for control and diagnosis. In a preferred embodiment, impedance measurements are obtained for determining the timing of right heart valve closure or right ventricular contractions, and the timing of delivery of left ventricular pace pulses is adjusted so as to optimally synchronize left ventricular pacing with the right ventricular contractions.

Abstract: A method and apparatus for treating gastric arrhythmia. The apparatus features an implantabler pulse generator which may be coupled to the gastric system through one or more medical electrical leads. In the preferred embodiment the leads couple to the circular muscle layer of the stomach. The apparatus further features a sensor to sense slow waves and determines whether the slow waves are occurring in an irregular or unstable manner. The apparatus further permits such slow waves to be diagnosed as either occurring in a bradygastria or a tachygastria and provides the appropriate electrical stimulation in response. Thus the present invention diagnoses and treats irregular gastric rhythm such as bradygastria and tachygastria.

Abstract: There is provided a system and method for determining, in a DDD or DDD(R) pacing system, when a delivered atrial pace pulse has failed to capture the patient's atrium. Each cycle, following a delivered ventricular pace pulse, or every N cycles a measure of change in QT interval is obtained and compared to stored criteria. When an atrial pulse has achieved capture, the difference in QT from the last beat will be small, normally less than 2 ms. However, if there has not been atrial capture, the delivered ventricular pace pulse is in fact asynchronous with respect to the atrium, and under these circumstances the change in QT is greater than 2 ms, e.g., in the range of 2-10 ms. Accordingly, when the pacemaker sees a change in QT within the 2-10 ms range, this indicates failure of capture, and responsive action is taken by either directly incrementing the energy level of the atrial pace pulses, or performing an atrial threshold search and then resetting the atrial pace energy level.

Abstract: An implantable medical device such as a defibrillator is described. The device includes an hermetically sealed housing containing a flat electrolytic capacitor and an energy source such as a battery. The battery is connected to the capacitor and provides charge thereto. The capacitor stores the charge at a relatively high voltage. The charge stored in the capacitor is discharged through a defibrillation lead to a site on or in the heart when fibrillation of the heart is detected by the implantable medical device. Methods of making and using the implantable medical device, the capacitor, and their various components are disclosed.

Abstract: The present invention generally relates to implantable medical devices and more particularly to various means for ultrasonically welding, swaging or staking various components in an implantable medical device, most preferably by employing appropriately configured covers or lids. Covers or lids are attached to header or connector modules mounted on an hermetically enclosed and sealed enclosure, where the connector or header module and enclosure comprise an implantable medical device. The covers or lids preferably trap or otherwise secure any of a number of various connector or header module components within the header or connector modules. Examples of such trapped or secured components include grommets, set screw connector blocks, seals, feedthrough wires, multi-beam contacts, electrical contacts, antennas, radio-opaque markers, connector ribbons and the like.

Abstract: An implantable drug infusion device which features an improved flow regulator which permits the flow rate to be independent of reservoir pressure within a given pressure range. The flow regulator features a membrane having a hole, the membrane itself positioned above a bottom layer such that sufficient deflection of the membrane causes the membrane to engage against the bottom layer. As liquid flows through the hole a drag force is applied to the edge of the hole resulting in a deflection of the membrane. Once contact is made between the membrane and the bottom layer, then flow reduced. In a further embodiment the bottom layer features a variable flow channel such that upon membrane deflection flow may only proceed through the hole and through the flow channel. By tailoring the shape and length of the variable flow channel the flow characteristics of the regulator versus pressure may be adjusted. In a further embodiment the flow regulator also features a flow sensor integrated therewith.

Abstract: A peripheral memory patch apparatus for attachment to a patient's skin includes a high capacity memory for storing physiologic data uplinked from an implantable medical device. A resilient substrate provides support for a memory, microprocessor, receiver, and other electronic components. The substrate flexes in a complimentary manner in response to a patient's body movements. The substrate is affixed to the patient's skin with the use of an adhesive which provides for comfort and wearability. The low profile peripheral patch apparatus is preferably similar in size and shape to a standard bandage, and may be attached to the patient's skin in an inconspicuous location. A status indicator provides for a visual, verbal, or tactile indication of the operational status of the peripheral memory patch.

Abstract: An ambulatory data recorder with enhanced infrared data transfer. In particular, the device features an infrared transmitter port having a multi-plane lens. The port, lens and recorder enclosure work together to permit a reliable infrared data link to be established between the recorder and a line voltage device even while the recorder is in a variety of positions. That is, the infrared data link may be established when the device is worn, of when the device is placed on a table in a variety of positions.

Abstract: An implantable sensor assembly for use with an implantable medical device are disclosed. The sensor assembly preferably includes two or more physiologic sensors coupled to the medical device via a pair of lead conductors, or alternatively an oxygen sensor having certain features. The oxygen sensor permits more accurate and reliable measurement of oxygen saturation in blood masses flowing within the human body.

Abstract: A medical lead adaptor that provides a rapid, secure, insulated connection of the lead connector end assembly of a cardiac lead having electrodes adapted to be placed in or on the body with an external medical device is disclosed. The adaptor connector assembly is configured with an elongated receptacle to accept a bipolar, in-line, or a unipolar lead connector end sharing common dimensions. The elongated receptacle includes connector pin and ring receptacle contacts spaced apart from one another therein. In a preferred embodiment, an elongated slot that extends laterally of the elongated receptacle cooperates with a lock mechanism to allow the lateral insertion of the lead connector end assembly, with a stylet wire inserted into the cardiac lead body lumen, into the elongated receptacle. When inserted therein, the lead connector ring and/or pin are nested into contact with the ring and/or pin receptacle contacts and are held there by the lock mechanism.

Abstract: A pulse waveform is provided to at least one surface of an implantable device to protect it from corrosion from a corrosive fluid. The pulse waveform can be delivered through ether anodic or cathodic monophasic or asymetrical biphasic pulses using one electrode and an indiferent or sacrificial electrode. The electrode and the indiferent or sacrificial electrode are oriented such that a closed circuit between the two electrodes is completed through the corrosive fluid and the surface to be protected is within the completed circuit path.