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 transvenous lead specifically designed for multi-chamber electrical stimulation or sensing. In a first embodiment the lead features one or more electrodes for communication with the right atrium as well as one or more electrodes for communication with either or both of the left chambers of the heart. The lead further features structures to simultaneously bring the first electrode into contact with a first chamber, such as the right atrial wall and the second electrode into contact with a particular portion of the coronary sinus wall, to electrically access the left atrium or ventricle. In the preferred embodiment the lead body has varying flex or stiffness characteristics along its length between each of the electrodes.

Abstract: There is provided a pacemaker system with capture verification and threshold testing, in which the pacemaker adjusts the post-stim pulse portion of a triphasic pulse to minimize polarization, and waits after each change in delivered pace pulses for a stabilization interval, in order to enhance capture verification. The threshold test utilizes a pace pulse pair, comprising a prior search pulse which is varied during the test, and the regular pacing pulse which is above threshold. When delivery of the pulse pairs is initiated, the search pulse is adjusted to optimize polarization, and the pacemaker waits for a predetermined stabilization period of time in order to allow for minimum polarization and to optimize capture detection. The search pulse is increased incrementally in output value toward threshold, and following each such increase the pacemaker waits for a stabilization interval. The pacemaker detects when capture is achieved by the search pulse, thereby providing an indication of threshold.

Abstract: A system to provide cardiac assistance to a patient's heart. The system includes a pulse generator adapted to be coupled to patient's heart and adapted to be coupled to a skeletal muscle ventricle (SMV). The system further includes a sewing ring adapted to be coupled to the SMV and adapted to be coupled to the patient's circulatory system, the sewing ring has a first annular ring and a second annular ring, the first and second annular rings having means for limiting the formation of tissue fibrosis in the vicinity of the first and second annular rings. In the preferred embodiment this comprises means for being more flexible at a distal end than a proximal end, which is accomplished by providing a series of holes in each of the rings. The holes preferably have a range of diameters, the holes located furthest away from the distal end of each ring have smaller diameters than compared to those holes located nearer to the distal end of the same ring.

Abstract: The present invention is a system for ablating tissue within a body, the system having: an energy source providing a level of energy which is non damaging to the cellular structures of the body tissue, a catheter coupled to the energy source, the catheter having an electrode; and means for sensing the temperature of the electrode while also sensing the amount of energy which is non damaging to the cellular structures of the body tissue is delivered to the electrode, the sensing means coupled to the catheter and coupled to the energy source wherein the degree to which the electrode contacts the heart tissue (e.g. no contact, moderate contact, good contact or excellent contact) may be determined.

Abstract: A system and method are provided for inducing ventricular tachycardia in a patient to enable testing to determine the optimum parameters for anti-tachycardia stimulation. The implantable device provides for overdrive pacing of the heart for a short sequence, followed by delivery of a series of pulse pairs. Each pulse pair has a first stimulus pulse delivered at the same or similar overdrive rate, and an inducing pulse which is delivered in timed relation to the evoked T-wave, preferably during the falling edge portion of the T-wave. In this way, each cycle the inducing pulse is timed for efficaciously inducing tachycardia. The timing of the inducing pulse is enhanced by near field sensing of the T-wave at about the location where the pulses are delivered, preferably using bipolar sensing and/or sense circuitry designed to recover the signal with an optimum time response.

Abstract: An implantable medical pump featuring a low power multi-stable valve. In particular, the present invention features a valve constructed using an electrolytic fluid, the fluid releasing a gas when subject to an electronic current, the same gas absorbed again by the fluid when such current is removed. The fluid is further housed within an uniquely designed actuation chamber such that the out-gassing of the fluid deforms the membranes defining the chamber. The membranes, in turn, are positioned such that this deformation will inhibit or completely restrict the flow pathway between the reservoir and ultimately the patient. Through such a design a valve is provided which has complete variability in the possible flow rates but which uses a minimal amount of electronic current. Moreover, the valve has the additional safety feature of being in the normally closed position when no energy is provided.

Abstract: There is provided an implantable cardiac pacing system or other cardiac monitoring system, having an enhanced capability of classifying intracardiac signals through a combination of DSP techniques and software algorithms. The implantable device has one or more DSP channels corresponding to different signals which are being monitored. Each DSP channel provides for amplification of the incoming signal; conversion from analog to digital form; digital filtering of the converted signals to provide filtered signals; operating on the filtered signals to provide slope signals; determining from the filtered and slope signals whenever an intracardiac event has been detected, e.g., R wave, P wave, etc.; and signal processing of the filtered and slope signals for a predetermined analysis interval after threshold crossing, for generating a plurality of signal parameters.

Abstract: A method for making a medical device having a biomolecule immobilized on a substrate surface is provided. The method includes coating the substrate surface with an amino-functional polysiloxane; and contacting the amino-functional polysiloxane coated surface with a biomolecule under conditions effective to immobilize the biomolecule.

Abstract: An anticonstipation apparatus, and method, that may include using an implanted stimulus generator that may supply electrical stimuli to the muscles associated with a target portion of the patient's gut, from the esophagus to the anus, through an electrical lead and several pairs of electrodes. The electrical stimuli may be provided to nerves in the autonomic nervous system that are associated with the muscles, or the stimuli may be provided directly to the muscles themselves. The stimuli may be provided sequentially, in a proximal to caudad direction, in order to initiate, enhance or artificially produce peristalsis in the gut's target portion in a proximal to caudad direction. If the gut's target portion is in the descending colon, such stimulation may be coordinated with similar stimulation of the muscles associated with the rectum and anus. A sensor may be provided to detect when the target portion is experiencing constipation.

Abstract: An ambulatory recorder which features a method of configuring the size of data subject to loss in volatile memory. The recorder of the present invention determines how many processor sampling cycles it will take to fill the memory buffer. As discussed above this will vary a great deal and will directly depend upon the programmed parameters, e.g. number of channels to be sampled and the various sampling frequencies. The device then determines the amount of time this number of processor sampling cycles will take. If this amount of time is greater than a pre-selected amount of time, then the number of sampling cycles is reduced to be less than the pre-selected amount of time. The recorder uses these calculations to thereby schedule the transfer of data from the volatile memory to the non volatile memory. Through such an operation the data in the memory buffer subject to loss is limited to only a pre determined amount of time, i.e.

Abstract: A system and method for locating an implantable medical device. The system consists of a flat "pancake" antenna coil positioned concentric with the implantable medical device target, e.g. the drug reservoir septum. The system further features a three location antenna array which is separate from the implantable device and external to the patient. The antenna array features three or more separate antennas which are used to sense the energy emitted from the implanted antenna coil. The system further features a processor to process the energy ducted by the antenna array. The system senses the proximity to the implant coil and, thus, the implant device by determining when an equal amount of energy is present in each of the antennas of the antenna array and if each such ducted energy is greater than a predetermined minimum. When such a condition is met, the antenna array is aligned with the implant coil. Thus the needle port through the antenna array is lined up with the septum of the drug reservoir.

Abstract: The present invention is directed to a single pass medical electrical lead. In one embodiment, the lead features a pair of bipolar electrodes positioned along the lead body so that they are positioned in the ventricle and atrium respectively when the lead is implanted. The lead body features a 90 degree bent reinforced section. The bend has a radius of curvature approximately 13 mm and begins approximately 90 mm from the distal end. This curved section is approximately 40 mm in length when straightened. The ventricular electrodes are positioned approximately 28 mm apart. The bend has at least one tine extending therefrom, an electrode is mounted on the tine.

Abstract: A transvenous lead specifically designed for coronary sinus implantation. The lead features a fixation ring positioned adjacent to the electrode. The ring is constructed so as to be readily pliable and bent. The ring functions to wedge or fix the lead within the coronary sinus in such a manner that the electrode is pushed against the vessel wall while the flow of blood through the vessel is not impeded. In alternative embodiments the electrode is positioned on the ring itself. In further alternative embodiments the distal portion of the lead features a pre bent nose to assist in the positioning of the lead into the coronary sinus. The nose may be oriented relative to the ring in any acceptable manner to permit the ring and the electrode to be properly positioned relative to anywhere along the coronary sinus wall.

Abstract: There is provided an improved telemetry system for use with implantable devices such as cardiac pacemakers and the like, for two-way telemetry between the implanted device and an external programmer. The system employs highly energy efficient oscillators with encoding circuits for synchronous transmission of data symbols, which symbols form the telemetry carrier. The system provides improved circuits for higher density data encoding of sinusoidal symbols, including improved combinations of BPSK, FSK, and ASK encoding. Embodiments of transmitters for both the implanted device and the external programmer, as well as modulator and demodulator circuits, are also disclosed, and specifically include oscillators which switch capacitors between a tank circuit and a recharge path, the switching being controlled to occur at moments of substantially zero coil current, thereby providing high efficiency operation.

Abstract: A stent which minimizes or solves the problem of restenosis. The present stent is designed so as to have a cyclical change in diameter, the change in diameter corresponding to the changes in blood pressure caused by the cardiac cycle. The present stent is constructed through several structural members, each structural member interlocking in a fashion which permits the stent diameter to be altered from a first, diastolic diameter to a second, systolic diameter. This variable diameter is provided through a series of joints between the interlocking structural members. The joints may be provided in any acceptable manner, including an interlocking dog bone configuration, an interlocking elastic coupling, mating struts, as well as interlocking guides.

Abstract: There is provided an implantable cardiac pacing system, having multiple sensing channels for sensing spontaneous cardiac signals which arise between respective different pairs of electrodes. In a preferred embodiment, the system utilizes a single pass VDD-type lead, having at least one atrial ring electrode for sensing atrial signals, and at least a distal tip electrode positioned in the right ventricle for sensing ventricular signals. Sensing channels concurrently process signals between the atrial ring and the pacemaker can (the indifferent electrode); the ventricular tip electrode and the pacemaker can; and the between the atrial ring and the ventricular tip. One or more additional electrode pairs can also be employed. Enable signals selectively enable the channels to be used for concurrent processing of the signals.

Abstract: A calibrated medical sensing catheter system in which a catheter-mounted sensor may be calibrated in a simple and reliable manner. In one embodiment the calibration may be performed using a disposable vessel containing two volumes of calibrating fluid, each volume separately accessible by the sensor to be calibrated. Preferably, such a vessel takes the form of an elongated tube having a first volume at one end and a second volume at the other end, each volume containing distinct calibrating fluids. Each volume may be accessed through the respective ends of the tube by introducing a sensor through a pierceable membrane, such as a foil-plastic membrane or seal. In an alternative embodiment the calibrated vessel takes the form of an elongated cylinder having two separate volumes of calibrating fluid separated by a common pierceable membrane or seal.

Abstract: A method and apparatus for providing electrical stimulation of the gastrointestinal tract. The apparatus features an implantable 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 layer of the stomach. The pulse generator preferably features sensors for sensing gastric electrical activity, and in particular, whether peristaltic contractions as occurring. In particular two sensors are featured. The first sensor senses low frequency gastrointestinal electrical activity between the frequency of 0.017-0.25 Hz and the second sensor senses intrinsic gastrointestinal electrical activity between the frequency of 100-300 Hz, which occurs upon normal peristaltic contractions. The second sensor only senses for a preset period after low frequency gastrointestinal electrical activity has been sensed by the first sensor.

Abstract: The present invention is directed to a single pass medical electrical lead. In one embodiment, the lead feature a pair of bipolar electrodes positioned along the lead body so that they are positioned in the ventricle and atrium respectively when the lead is implanted. The lead body features a 90 degree bent reinforced section. The bend has a radius of curvature approximately 13 mm and begins approximately 90 mm from the distal end. This curved section is approximately 40 mm in length when straightened. The ventricular electrodes are positioned approximately 28 mm apart. The ventricular cathode electrode is positioned at the distal end of the lead. The atrial electrodes are positioned approximately between 5-35 mm apart, with 28 mm preferred. The atrial anode is located at a position immediately adjacent and proximal the 90 degree bent reinforced section.