Abstract: An inline electromagnetic flow probe, and its corresponding flow transducer, incorporate mutually compatible features that permit a single transducer to identify which of a plurality of types of flow probes has been inserted into the transducer.

Abstract: A method of making a spring are described. The spring is made by etching or cutting at least one spiral arm in a flat substrate leaving residual material around the arm. The intermediate residual material is either pushed or lifted to form a conical spring.

Abstract: A low-cost temporary lead for pacing, sensing, monitoring, or defibrillating at least a portion of a human or animal organ, and methods for implanting and making same. The lead has at least two electrodes and distal and proximal ends, and a novel weakened zone disposed between the blunt end of a needle and at least two electrical connectors attached to the proximal end of the lead body. The novel weakened zone permits the needle to be separated from the connectors by application of a sufficiently large bending moment or pulling force thereto. Following separation of the connectors from the needle, the connectors may be attached directly and quickly to an external electrical apparatus.

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. 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: An electrocautery instrument is provided with a hollow electrode having a source of conductive fluid coupled to a proximal end thereof. Conductive fluid is communicated through said electrode and expelled out of the distal end thereof during electrocautery, forming a “virtual electrode.” The infused conductive liquid conducts the RF electrocautery energy away from the conductive electrode, thereby displacing the region of thermal generation and reducing the extent of burns and perforations caused by conventional electrocautery electrodes. In one embodiment, the electrode is partially disposed within and extends distally out of a retractable suction tube, such that smoke and fluid are aspirated from the electrocautery site. When the suction tube is fully advanced. the electrode is concealed therein, enabling suction without electrocautery to be performed.

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: A system for communicating with a medical device implanted in an ambulatory patient and for locating the patient in order to selectively monitor device function, alter device operating parameters and modes and provide emergency assistance to and communications with a patient. The implanted device includes a telemetry transceiver for communicating data and operating instructions between the implanted device and an external patient communications control device that is either worn by or located in proximity to the patient within the implanted device transceiving range. The control device preferably includes a communication link with a remote medical support network, a global positioning satellite receiver for receiving positioning data identifying the global position of the control device, and a patient activated link for permitting patient initiated personal communication with the medical support network.

Abstract: An introducer or guide catheter for directing an implantable medical device such as a lead or catheter to a desired location within a patient's body. In one embodiment of the invention, the introducer comprises a two-lumen tube. A first lumen is configured to receive the implantable medical device that is to be introduced. A second lumen is provided to receive an insertable, elongated guiding member such as a stylet, which may be shapable in various orientations, and which may be used to alter the configuration of the introducer. The second lumen may be provided with an internal coil or other tubular reinforcement member to prevent perforation of this lumen by the guiding member when the introducer is in the patient's body. In order to facilitate removal of the introducer over an implantable medical device having a connector or fitting that is larger than the internal diameter of the first lumen, the introducer may be adapted to be slit or split along its length.

Abstract: A flux-gate magnetometer having a drive signal for reducing the effects of electromagnetic interference (EMI) is provided. The drive signal has a characteristic that varies over time. For example, the drive signal may include a duty cycle that varies over time, the frequency of the drive signal may be varied over time, or the phase shift of the drive signal may vary over time.

Abstract: An elongate elastomeric structure having controlled surface texture. Plasma deposition is used to create controlled features, such as ridges, on the external surface of an elongate elastomeric surface, such as the external surface of silicone tubing. The invention has particular applicability in the medical device field, such as the fabrication of implantable leads, catheters, and medical devices incorporating them.

Abstract: An implantable antiarrhythmia device which detects and classifies arrhythmias of the human heart, and delivers appropriate therapy. The device employs a method of arrhythmia classification based on a set of prioritized rules, each of the rules defining a plurality of criteria based upon characteristics of sensed depolarizations of heart tissue, each rule being met when the criteria associated with the rule are met. Some rules, when met, trigger delivery of antiarrhythmia therapy. Other rules, when met, inhibit delivery of antiarrhythmia therapy. The rules may be met simultaneously, and if so, the highest priority rule governs the behavior of the device.

Abstract: A method of sensing fluid pressure in which a deformable tube provides an accessible and substantially flat section. Deflection of the flat section reflects line pressure. In one embodiment, a fluid pressure sensing apparatus comprises a deformable tube for carrying fluid and at least one constraint member comprising an inner surface and a pressure sensing opening. The inner surface comprises a substantially flat portion and a constraint portion. The tube is positioned against the inner surface and constrained by the constraint portion such that a portion of the tube is deformed against the substantially flat portion of the inner surface. This produces a substantially flat section of the tube adjacent to, and accessible through, the pressure sensing opening. Similarly, a method of manufacturing a fluid pressure sensing apparatus comprises the steps of: providing a deformable tube, and constraining the tube to provide an accessible and substantially flat section of the tube.

Abstract: Methods and apparatus for communication of implantable medical device (IMD) information, including confirmation of programming and programmed parameter values, operating modes and programmed changes thereof and data stored in the IMD, by emission of audible sounds by the IMD are disclosed. The IMD includes an audio transducer that emits audible sounds including voiced statements or musical tones stored in analog memory correlated to a programming or interrogation operating algorithm or to a warning trigger event. The audible sounds can comprise the sole uplink transmission or may augment the contemporaneous uplink RF transmission of stored data, and/or programmed operating modes and parameters and/or device operations and states in an interrogation or during programming. To conserve energy, the audible sounds accompanying interrogation and programming of the IMD are at a low volume that preferably cannot be heard without use of an external audio amplifier or stethoscope.

Abstract: An implantable medical device having an hermetically sealed enclosure housing electrical and electronic circuitry and a battery for powering such circuitry is connected to an intracranial lead or pigtail which measures or senses intracranial physiologic signals such as intracranial fluid pressure and/or temperature. The implantable medical device is preferably implanted subcutaneously beneath a patient's skin and telemeters stored data or real-time-sensed data to an external device which may be configured to combine barometric pressure data with intracranial pressure data to derive intracranial gage pressure. The implantable medical device and its associated lead reduce the risk of intracranial infections.

Abstract: A left atrium ablation catheter (4), including a sheath (8) and a deflectable electrophysiology catheter (10) housed within the sheath, is used to ablate coronary tissue at a target site within the left atrium (LA) of a heart. The electrophysiology catheter has ablation electrodes (24) along the tip (10). The ablation catheter is introduced into the right atrium (RA) through either the superior vena cava (SVC) or the inferior vena cava (IVC). The distal open end of the sheath is guided through a punctured hole in the interatrial septum and into the left atrium. The distal end (20) of the sheath is either precurved or is steerable so the electrode tip can be directed to the coronary target site in the left atrium. The electrode tip is sized and configured to create the desired lesion at the target site without movement of the electrode tip.

Abstract: A length of living conductive cells may be injected directly or may be grown to be attached to a fibrous matrix of material that provides for flexible structure so as to deliver a stimulation signal from one end of the biologic cable to the other to induce a physiologic reaction in body tissue.

Abstract: A method and apparatus for creating a virtual electrode to ablate bodily tissue. The apparatus includes an outer tube, a first electrode, an inner tube and a second electrode. The outer tube is fluidly connected to a source of conductive fluid and defines a proximal end and a distal end. The distal end includes an opening for delivering conductive fluid from the outer tube. The first electrode is disposed at the distal end of the outer tube for applying a current to conductive fluid delivered from the outer tube. The inner tube is coaxially received within the outer tube and is connected to a source of conductive fluid. The inner tube defines a proximal end and a distal end, with the distal end forming an opening for delivering conductive fluid from the inner tube. Finally, the second electrode is disposed at the distal end of the inner tube for applying a current to conductive fluid delivered from the inner tube.

Abstract: An implantable medical device for delivering a medical therapy or for monitoring physiologic parameters. The device is provided with a hermetic housing containing a transceiver coupled to an antenna located outside the housing by means of a feedthrough, mounted to the housing and coupled to the transceiver. The antenna takes the form of a length of conductor, coupled to the feedthrough. In some embodiments the antenna is an insulated stranded conductor coupled to the feedthrough by means of a metallic loading tab. In other embodiments the antenna includes a length of conductor encased in a dielectric, extending from the feedthrough, and a coaxial shield coupled to the housing and extending along only a portion of the length of conductor.

Abstract: A pacemaker having a hysteresis feature which permits intrinsic heart activity, controlled by the sinus node to resume optimally after pacing. The pacemaker has a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable rate (IR) intermediate an upper pacing rate (UR) and a lower pacing rate (LR). A microprocessor measures the average rate of change MAVG in the intervals between consecutive ventricular depolarizations, and compares the last intrinsic escape interval RRN to the lower rate hysteresis interval (LRHI). If the last intrinsic escape interval RRN is longer than the lower rate hysteresis interval (LRHI), and if the value of MAVG is greater than a first preselected value SL1 but less than a second preselected value SL2, the pacemaker stimulates at the lower rate hysteresis (LRH) and thereafter gradually increases the pacing rate up to the intermediate rate (IR).

Abstract: Clinical studies of heart patients have demonstrated that ventricular tachyarrhythmia often is preceded by a foreshortened cardiac cycle length followed by a relatively long compensatory pause, thus producing in an abrupt short-to-long cycle length change. An implantable apparatus for preventing tachyarrhythmia measures the cardiac cycle length and detects the occurrence of a foreshortened cardiac cycle length more than a predefined amount between consecutive cycles. When a normal heart beat does not occur within a predefined period of time after such an abrupt change in cycle length, the resulting compensatory pause is eliminated by a cardiac pacer applying an appropriately timed electrical pulse to produce a contraction of the heart. The apparatus also includes a defibrillator to shock the heart in the event that the preventive pacing is not effective.