Abstract: A method and apparatus for determining the availability of unipolar and/or bipolar pacing/sensing paths in a body-implantable cardiac pacing system. In one embodiment, a pacemaker system includes impedance monitoring circuitry for periodically measuring impedance between pairs of electrodes that are potentially available for pacing and/or sensing. This impedance monitoring circuitry includes circuitry for delivering excitation pulses between pairs of potentially available electrodes (including the pacemaker canister in the case of unipolar pacing or sensing), and for monitoring the current and voltage between those pairs of electrodes during delivery of an excitation pulse. Availability of a pair of electrodes for pacing and/or sensing is indicated if the impedance between a pair of electrodes is found to lie within a predetermined range.

Abstract: An electrode system for an implantable cardioverter defibrillator. The electrode system includes a conductive structure which is physically and electrically connected to the housing or can of the implantable cardioverter defibrillator and is used as an electrode in combination with an existing implantable cardioverter defibrillator electrode or electrodes. The electrode system provides a therapeutically significant increase in the effective surface area of the implantable cardioverter defibrillator's electrodes without requiring an additional header connection, feedthru, or cable.

Abstract: An electrode assembly of a lead to be implanted on a patient's nerve includes a flexible electrically insulative carrier of helical configuration, a flexible ribbon electrode secured to the underside of at least a segment of the helical configuration carrier, an elongate conductor for electrical connection to the ribbon electrode, and a flexible conducting spacer electrically connected to the ribbon electrode and to the elongate conductor for separating the latter from the helical configuration while maintaining electrical connection between the two at the distal end of the elongate conductor. The distal end of the conductor projects directly and tangentially from a curved portion of the spacer in a direction substantially parallel to the longitudinal axis of the helical configuration.

Abstract: A medical electronic device having an electronic circuit allows for additional functional modules having electrical components to electrically couple to the medical electronic circuit. The modular system includes a housing enclosing the medical electronic circuit and a module enclosing the electrical components containing the additional functionality. A socket for releasably receiving the module is formed in a top side of the housing and is defined by a bottom wall and a side wall of the housing. The side wall has a rib projecting therefrom and extending from the bottom wall toward the top of the housing. The bottom wall has first and second holes formed therein proximate to the first rib. The module includes front and rear sides each having a channel formed therein for receiving the rib. A pair of guide pins extend below the bottom of the case, on opposing sides of an electrical connector.

Abstract: A novel operating table system is provided herein. The operating table system includes a table formed of non-magnetic material. A support is provided for such table. Magnetic means are provided for applying a magnetic field around a defined area of the table. The magnetic means includes one pole below the table and a second pole disposed a selected spaced-distance above the table. The second pole includes controls for selectively focusing and translating the electromagnetic field by way of manipulation of the second pole.

Abstract: A method of measuring lung function in a subject includes connecting a pneumotach in series with the subject's airway and taking pressure readings upstream and downstream of a fixed resistance element in the pneumotach. Second pressure readings are taken with a second resistance element in place, and the sets of readings are processed to calculate characteristic flow curves for the subject's airway. First and second time constants are calculated from the flow curves, and are used to calculate values of lung compliance and airway resistance. The invention extends to a pneumotach device with a fixed first resistance element and a removable second resistance element. The invention also extends to apparatus for monitoring lung function including the pneumotach device, together with a pair of pressure sensors and a processor circuit for carrying out the necessary calculations of the time constants, and the lung compliance and airway resistance values.

Abstract: A joint for cardiac stimulation lead has a sleeve that joins a conductor to an electrode. The conductor and electrode are inserted into passages formed through the sleeve and are bonded at least to the sleeve surface by laser welding, crimping, or resistance welding. The distal end of the conductor is attached to the sleeve and either the proximal end or the distal end of the electrode may be attached to the sleeve. The number, size, shape and positioning of passages in the sleeve are varied according to the desired lead configuration to allow passage of additional conductors through the joint.

Abstract: Process of control of an implantable active medical device. The device is under the responsive control of (enslavement to) a sensed physiological parameter. A representative magnitude of the physiological parameter is measured in the presence of a useful signal to determine a value of the parameter. Then, in the absence of the useful signal, another measure is made to determine the noise. The noise is compared to a threshold corresponding to an unacceptable level of noise. In case of crossing the noise threshold, this crossing is taken in account by a control device with a view to possible suspension of a function of the device if there is too much noise.

Abstract: The amplitude of a pulse wave that appears in a form superimposed upon cuff pressure is detected every beat of a heartbeat in synchronism with the beat not only in the course of depressurization but also in the course of pressurization. The maximum value Amaxi of the pulse-wave amplitude in the course of pressurization is multiplied by a prescribed coefficient to decide a threshold value TH. The threshold value TH is calculated as a value equivalent to a pulse-wave amplitude corresponding to systolic pressure that would be determined in the course of depressurization. After the cuff is pressurized to the target pressure, a transition is made to the depressurizing process. It is judged that cuff pressurization is inadequate if the initial pulse-wave amplitude in the course of depressurization is greater than the threshold value TH. Thus, whether or not cuff pressurization is inadequate can be judged appropriately at all times without any influence due to personal differences or physical condition.

Abstract: A partial body plethysmograph is provided to enable accurate modeling of a human's respiratory system for input frequencies of up to about 96 Hz using transfer impedance measurements. One preferred embodiment comprises a container for sealingly enclosing a portion of the subject's body, a pressure source for generating pressure signals over a predetermined frequency range, an air flow sensor for measuring the flow of air supplied to the subject, a pressure sensor for measuring the pressure applied to the cavity of the subject and a processor for controlling the pressure source, for storing the measured air flow and pressure and for determining the respiratory system impedance of the subject. An eight element model is used by the processor to inversely model the transfer impedance data and thereby determined characteristics of the respiratory system of the subject.

Abstract: Described is a low voltage, multipoint auricular stimulator which is lightweight, portable and unobtrusive for use by a patient to reduce or eliminate sensations of pain and anxiety and for correcting other neural dysfunctions, and a treatment method incorporating the pain reducing and neural dysfunction correcting apparatus.

Abstract: An interferential stimulation device for providing transcutaneous electrical nerve stimulation to a living body. The device applies current at two difference frequencies, each across two contact points on the body, spaced about a selected crossing point. The different frequencies produce at the crossing point a low frequency beat by the heterodyne process for specific stimulation at the crossing point. Electronic circuitry is provided to generate the desired signals and apply them through body contacting pads. Several modes for changing the stimulation smoothly, with the interference beat frequency ramped over a selected range over a selected time period provides superior results and prevents accommodation to the device. Several different ramp beat frequency ranges are provided, including a long range ramp, a relatively low frequency ramp and a relatively high frequency ramp.

Abstract: A defibrillator, such as an atrial defibrillator, applies cardioverting electrical energy to the atria of a heart when the atria are in need of cardioversion. The atrial defibrillator includes an atrial sense channel for sensing atrial activity and ventricular sense channels for sensing ventricular activity to generate heart activity data, a memory for storing the heart activity data, and a cardiovertor which applies cardioverting electrical energy to the atria if the heart activity satisfies a predetermined criteria. A storage control causes at least a portion of the heart activity data to be retained in the memory if the heart activity data fails to satisfy the predetermined criteria.

Abstract: In a portable electrocardiograph, a first measuring electrode that is to be held by a hand during measurement and comes into contact with the palm is provided on a body case. A second measuring electrode that to be pressed against the chest is provided on an arm member provided on the body case in foldable manner. The arm member is placed on the surface facing the body case when the arm member is folded onto the body case. Therefore, to measure electrocardiographic waves with this electrocardiograph, the user has only to slide the arm member into the opening between buttons on the front of his or her clothes or the opening in the shirt at the armpit, and then contacts the second measuring electrode with his chest for measurement. Therefore, it is not necessary to apply the apparatus perpendicularly to the chest. The user has only to place the apparatus almost in parallel to the chest and press the second measuring electrode against the left side of the heart in the chest.

Abstract: A pulse transducer is disclosed having a pressure sensor for detecting pulse pressure and a velocity sensor for simultaneously detecting pulse velocity in blood vessels. The present invention allows reproduction of pulse pressure and velocity waveforms. The present invention combines a conventional applanation tonometer with a mounted velocity sensor, such as a Doppler crystal. The velocity sensor is placed proximate to the pressure sensor to allow simultaneous detection of pulse velocity, in real time, at substantially the same location as the pulse pressure measurement. The sensing direction of the velocity sensor may be at an angle with respect to the sensing direction of the pressure sensor. The present invention may be applied vertically to a vessel for proper applanation, while ultrasound, traveling across the vessel, may be used to detect a major component of the velocity.

Abstract: A pacemaker system for a heart having an external muscle is used to control pacing of the heart during normal or even arrhythmic modes. In these modes, the muscle is stimulated synchronously with the heart to augment the heart's cardiac functions. When the heart undergoes ventricular fibrillation, the muscle is provided with a signal to cause the muscle to contract and expel blood from the heart chambers. Defibrillation shock is then applied to the heart to halt the fibrillation. The system is rendered more effective, safer and uses less power because the defibrillating energy is efficiently transferred to the heart muscles and not to the blood contained in its chambers. The system includes a microprocessor, muscle stimulating circuitry, defibrillation circuitry and an interface for exchanging signals between the microprocessor and the remaining components.

Abstract: TENS electrodes and connectors useful with such electrodes are disclosed. The electrodes include active electrodes and return electrodes having a common carrier with a field of pressure sensitive adhesive for adhering the electrode to a hand (finger or thumb) of the practitioner or to an applicator. Extraoral electrodes adhere to facial skin of mammals and provide TENS treatment for intraoral-procedures. The electrodes can be single channel or dual channel to combine active electrodes and return electrodes on one electrode. The connector can be single channel or dual channel and has a ridge for projecting through the tab portion of the electrode for more secure mechanical and electrical connection. Optionally, a dual channel electrode is used in combination with an elongated applicator having a bifurcated end in order to facilitate guiding a syringe needle toward a desired injection site. Assemblies of electrodes on alternative embodiments of release liners are also disclosed.

Abstract: An implantable cuff having an improved closure is disclosed. The closure has a set of small interdigitated tubes lying along the edges of a longitudinal slit opening in the cuff. A rod-like locking member is inserted through the interdigitated tubes to lock the cuff closed. A flexible flap attached to the inside of the cuff electrically and mechanically isolates the interior of the cuff from the exterior. The cuff has particular application as a nerve cuff for recording electrical nerve activity and for electrically stimulating nerves.

Abstract: The invention relates to a method for anticipating a change occurring in the condition of a patient's organism before the condition of a patient reaches a critical point, the condition of a patient's organism being monitored by the application of an appropriate measuring method and the determinations according to said measuring method being effected at appropriate time intervals. The measuring results obtained on the basis of effected measurements, the number of which must be at least two, or quantities derived therefrom are utilized for predicting the future development of one or more measuring results and, if a measuring result according to the prediction indicates that a limit value representing a predetermined critical point is reached in the condition of a patient within a predetermined period of time, a warning signal is released indicating that this critical point is being approached.

Abstract: An electrode catheter for intravenous insertion into a cavity of the heart comprises a tubular sheath accommodating a first spiral wound wire of conductive biocompatible material, which affords an insulated operative portion exposed from the sheath and capped distally by a domed ring, and a mapping electrode of conductive biocompatible material for sensing the electrical activity in the cardiac muscle, which is carried coaxially by the first spiral wound wire and capable of movement along the operative portion transmitted by means of a second spiral wound wire extending coaxially through the first and connected to an external control handset. The operative portion of the first wire is arched by means of a tension wire designed to establish a restraint between the domed ring and the distal end of the sheath, of which the length can be increased or reduced to alter the loop of the arched profile as expedient for the shape of the cavity explored.