Abstract: An implantable endocardial, multi-lumen lead wherein the distal end of the lead body is cored to provide a stopped bore co-axial with the axis of the lead body. A distal electrode is inserted into the stopped bore without an additional tubular segment and glue joint. A first lumen in the lead body has an axis which is off set from the axis of the lead body itself. A low voltage conductor passes through the first lumen. A second lumen is also offset from the axis of the lead body. The lumens may have a circular or other cross section. A plurality of non-coaxial lumens may be provided.

Abstract: Surface mount device packages with increased mounting strength and a method therefor. In one embodiment, an electronic device is made up of a device package and one or more electrically conductive terminals. For surface mounting, the device terminals are each provided with a mounting surface which is bonded using a conductive adhesive to a corresponding contact pad on a circuit board. The terminals are further provided with at least one groove across the mounting surface. When conductive adhesive is used to mount the device on a circuit board, this groove serves to form the conductive adhesive into a ridge or “dam” over the contact pad. This provides increased mounting strength which may eliminate the need for additional adhesive material to provide side reinforcement of the device, and thereby allow an increase in the packing density of devices on the circuit board.

Abstract: A system is provided for optically communicating with an implantable device. In one embodiment, the system includes an implantable device having a large memory and an external unit which downloads information from the memory for analysis and display. The implantable device includes a light-emitting diode (LED) and a modulator for driving the LED. Although various frequencies can be used, frequencies which experience relatively little attenuation through body tissue are presently preferred. The external device includes a photo-multiplier tube (PMT) and a demodulator for equalizing and demodulating the detection signal produced by the PMT in response to detected light. A high bandwidth channel (perhaps as much as 500 Mbits/sec) is created by these components. This channel advantageously allows for a substantially reduced download time.

Abstract: An electrode for a cardiac lead and method of making the same are provided. The electrode includes an electrode member and a coating applied to the electrode member. The coating is composed of an electrically insulating material and covers a first portion of the exterior of the electrode member while leaving a preselected second portion thereof exposed. The second or exposed portion enhances the impedance of the electrode, resulting in power savings and extended life spans for implantable stimulation and sensing devices. Exemplary materials for the coating includes diamond-like carbon and sapphire.

Abstract: It has been determined that certain dual-chambered cardiac stimulators may operate in a region in which an atrial pacing event may obscure the detection of a ventricular tachyarrhythmia. Various exemplary techniques may be used to improve the ability of dual-chamber cardiac stimulators to detect such ventricular events. In accordance with one technique, it is determined whether a ventricular event should be classified as a ventricular tachyarrhythmia. If not, the VA interval is restarted as usual. However, if the ventricular event may be classified as a ventricular tachyarrhythmia, it is determined whether the ventricular event falls within the region in which an atrial pacing event may obscure its detection. If not, then the VA interval is restarted as usual. However, if the ventricular event falls within this region, the VA interval is restarted with the VT rate detection boundary.

Abstract: A memory device particularly useful in size-constrained electronic products, such as cardiac stimulators. To provide additional memory for such size-constrained products, memory chips are stacked one on top of another. The memory chips are configured to facilitate bonding without crossed contacts, using aligned bonding pads, vias, or castellations. Each memory chip also includes an address selection circuit that receives signals from one or more address lines to selectively enable and disable the memory chips in the stack.

Abstract: An implantable medical device for electrically stimulating the heart to beat generally includes a processor, a plurality of electrodes, a sense amplifier, a pulse generator, and a heart status monitor. The processor can determine when the patient has entered an environment of high electromagnetic interference. When this occurs, the processor forces the implantable device into a safe noise mode. While in the same noise mode (which preferably continues while the patient is experiencing the electromagnetic interference), the implantable device paces the heart on demand and inhibits pacing during the vulnerable period. The processor determines when the vulnerable period is occurring and when the heart needs to be paced by monitoring a status signal from the heart status monitor.

Abstract: An implantable endocardial defibrillation lead having an elongated lead body with multiple lumens therein. Windows, cut through the lead body, provide access to selected ones of the lumens at selected locations along the lead body. In addition, a method and an apparatus for forming windows in a multilumen lead body are disclosed. A ferromagnetic stylet is inserted into a selected lumen. The lead body is oriented in a jig by application of an electromagnetic field. A grinder or punch cuts a window into the selected lumen.

Abstract: A thin film capacitor for use in an implantable defibrillator. A first dielectric polymer filmlayer has a metallized film on one side thereof. A second dielectric polymer film layer has a metallized film on one side thereof. The first and second layers are overlain on each other and wound spirally with the metallized film of one layer adjacent the dielectric polymer of the other layer. The beginnings and ends of the first and second metallized films are offset from the respective beginnings and ends of the first and second polymer film layers. The dielectric layers can be tapered in increasing thickness toward the respective beginnings and ends of the layers. The dielectric layers can themselves comprise at least two layers of differing polymer materials, the preferred materials being polyvinylidene fluoride and polyester for improved energy density and self-healing properties.

Abstract: A manufacturing method and apparatus for dicing printed circuit boards is disclosed that permits PCB's to be manufactured with greater component density and cut less expensively. The disclosed method includes forming a raw substrate to include conductive traces, mounting components on the substrate, testing the PCB and then cutting off the waste edges. The PCB can be formed and tested with components mounted on one or both sides of the PCB, and the waste edges can be cut off even with components mounted on both sides of the board. A workpiece fixture is provided that includes a recessed cavity into which PCB components extend. Double-sided boards can be cut using the disclosed workpiece fixture. The cavity includes a vacuum hole through which suction is provided to hold the PCB in place during cutting. Additional vacuum holes preferably are provided to hold the wings in place after they are removed.

Abstract: A cardiac stimulator lead connector is provided. The connector includes a pin member that has a distal end and a first insulating sleeve coupled to the pin member. An annular member is coupled to the first insulating sleeve. A conductor sleeve is coupled to the annular member and a second insulating sleeve is coupled to the conductor sleeve. One or more conductor wires running from distal electrodes in a lead may be welded to the connector. The connector eliminates crimping as a mechanism to secure lead conductors to lead connectors.

Abstract: An implantable medical interventional device is adapted to provide therapy to a patient in whom the device is implanted to treat cardiac dysrhythmias including tachyarrhythmia. The device performs a plurality of functions corresponding to different levels of therapy for treatment of sensed dysrhythmias, including an electric shock waveform of predetermined energy content for delivery to the patient's heart to terminate at least one type of tachyarrhythmia. In response to cessation of the tachyarrhythmia after delivery of the electric shock waveform, the device promptly thereafter applies post-shock pacing pulses to the heart for a period of time sufficient to allow the heart to recover from the shock and to resume substantially normal sinus rhythm. The device may be upgraded by programming to select among the various functions as necessary to provide designated therapy by suppressing some functions and activating others.

Abstract: A cardiac stimulator lead is provided. The cardiac stimulator lead includes a connector for connecting to a cardiac stimulator and a flexible tubular sleeve that has a first end coupled to the connector and a second end. An electrode has a proximal end that is inserted into the second end of the sleeve. An annular member is disposed around the proximal end and the second end and is deformed to clamp the second end to the proximal end. A conductor wire is coupled between the connector and the electrode. The deformed annular member eliminates reliance on an adhesive-to-metal molecular bond as the sole or primary mechanism for securing the distal end of a lead sleeve to the tip electrode. Manufacturing and assembly time may be significantly reduced.

Abstract: A method and apparatus for evaluating heart rate variability of the heart of a person in order to forecast a cardiac event. A cardiac stimulator receives heart beat signals from the heart and determines a measurement of heart rate variability based on statistical data derived from the heart beat signals and sensing data derived from a sensor. This measurement of heart rate variability is compared with previously stored heart rate variability zones defining normal and abnormal heart rate variability. These zones are modifiable after the occurrence of a cardiac event. Once a cardiac event is detected, a pathway is computed which extends from a generally normal heart rate variability condition to an abnormal heart rate variability condition. Subsequent measurements of heart rate variability are compared with this pathway. Selective therapy regimes are initiated depending on the measurement of heart rate variability.

Abstract: A system for communicating information between a first medical device and a second medical device. A first transducer is connected to the first medical device. A second transducer is connected to the second medical device. Each of the transducers includes a pair of electrically separated electrodes. A means is provided for imposing an electrical potential across one pair of electrodes of one of the transducers and modulating the electrical potential according to the information to be communicated, to generate a modulated electric field. The other of the transducers is disposed within influence of the modulated electric field. A means is provided having inputs connected to the pair of electrodes of the other of the transducers for amplifying an electrical potential sensed between the pair of electrodes of the other of the transducers.

Abstract: A cardiac lead is provided that includes a connector for coupling to a cardiac stimulator and a first flexible insulating sleeve coupled to the connector. A second flexible insulating sleeve is coupled to the connector and has a portion positioned inside the first flexible insulating sleeve. A first conductor wire is provided that has at least a first loop and a second loop. The first and second loops are positioned between the portion of the second flexible insulating sleeve and the first insulating sleeve. A second conductor wire is provided that has a third loop. The third loop is positioned between the portion of the second flexible insulating sleeve and the first insulating sleeve. The first and second conductor wires are spiraled together so that the third loop is positioned between the first and second loops. The lead provides for the union of two conductors in a flexible structure that facilitates passage of a highly curved stylet.

Abstract: A technique is utilized for coupling a circuit component to a substrate. The circuit component, such as a die, includes a plurality of contacts on one of its surfaces. The contacts may take the form of gold bumps. Solder is placed between the contacts of the circuit component and the contact pads of a substrate. The substrate is heated to about the melting point of the solder, and pressure and ultrasonic energy are used to cause the solder to couple the contacts of the circuit component to the contact pads of the substrate.

Abstract: A medical system comprising a control device (referred to as a "planet") and a plurality of sensing and stimulating devices (referred to as "satellites") is disclosed. The satellites are relatively small devices that can be thoracoscopically attached to an exterior surface of the heart. The planet can be implanted if desired or, alternatively, externally retained. The planet is capable of wirelessly communicating (i.e., without a direct electrical connection) to each satellite. The planet individually commands each satellite to deliver pacing energy to the heart. Additionally, each satellite is capable of determining when a sense event has occurred at the site of that satellite and transmitting an encoded signal to the planet indicating that a sense event has occurred, along with an identifying code indicating to the planet which satellite detected the sense event.

Abstract: A cardiac stimulator capable of measuring pacing impedance includes a tank capacitor for delivering charge to the heart via device leads, a shunt resistor, and high-impedance buffers for measuring pacing current through the shunt resistor. Soon after the leading edge of the stimulation pulse, the voltage across the shunt resistor, as sampled by a high-impedance buffer, indicates lead and cardiac tissue resistance. Just prior to opening the pacing switch to terminate the stimulation pulse, the voltage across the shunt resistor is sampled by a high-impedance buffer and held once again to allow the capacitance of the lead/heart tissue to be calculated. In alternative embodiments, a high-impedance buffer measures the voltage between the tank capacitor and ground immediately following the stimulation pulse to allow estimation of the lead/heart tissue capacitance.

Abstract: An electrode for a cardiac lead and method of making the same are provided. The electrode includes an electrode member and a coating applied to the electrode member. A method of fabricating a high impedance cardiac lead electrode is provided. The method includes the steps of providing an electrode member and coating a first portion of the electrode member with an electrically insulating material and placing a tubular mask or shield over the electrode. Portions of the insulating material are removed to expose selected areas of the electrode. The second or exposed portion enhances the impedance of the electrode, resulting in power savings and extended life spans for implantable stimulation and sensing devices. Exemplary materials for the coating includes diamond-like carbon and sapphire.