Abstract: A method and apparatus for delivering a waveform, including a predetermined series of electrical pulses, to the heart by electrodes positioned adjacent the heart. In a first embodiment of the invention, a series of four electrical pulses are delivered from an electrical pulse generator including a charged storage capacitor through two pairs of electrodes and define a waveform comprising two interleaved biphasic signals. The series of electrical pulses have a low defibrillation threshold and require a relatively small amount of energy.In a second embodiment of the invention, a triphasic waveform is applied to the heart through four electrodes. One of the pulses in the triphasic waveform is generated by all four electrodes and in a polarity opposite that of the other two pulses. The pulse generated by all four electrodes may be applied first, second, or third in the series of electrical pulses.

Abstract: An implantable defibrillator provided with a plurality of defibrillation electrodes, which may be reconfigured to define a plurality of defibrillation pathways. The device is capable of measuring the impedance along a selected defibrillation pathway, during delivery of an impedance pulse, and monitoring the success or failure of the pulse to accomplish defibrillation or cardioversion. In response to a detected failure to accomplish cardioversion in conjunction with a measured change of impedance of greater than a predetermined amount, a new defibrillation pathway is selected, which may employ some or all of the electrodes employed to define the original impedance pathway. The device also includes apparatus for varying the relative amplitude of defibrillation pulses applied to individual electrodes used in sequential or simultaneous, multiple electrode pulse regimens, in order to equalize current distribution, in response to measured pathway impedances.

Abstract: Systems and methods for non-invasive blood analysis for the presence of glucose are disclosed in which blood is illuminated at a plurality of discrete wavelengths selected from the near infrared spectrum. Measurements of the intensity of transmitted or reflected light at such wavelengths are taken, and an analysis of transmittance or reflectance ratios for various wavelengths is performed. Changes in the ratios can be correlated with specific near infrared (IR) absorption peak for glucose at about 1600 nm +/-15 nm which varies with concentration of the analyte (the data wavelength) and the a second (reference) wavelength being sufficiently removed from the first so that measurements of light absorption at this second wavelength are relatively insensitive to the concentration of the analyte and yet the second wavelength is sufficiently close to the first wavelength to minimize interference from scattering effects and the like.

Abstract: A cardiac pacing system includes circuitry for verification of capture having an indifferent electrode mounted on the pacemaker connector top. The cardiac pacing system may use one or two bipolar or unipolar leads. Capture is sensed between the indifferent electrode and one of the electrodes on the lead or leads. Either electrode on the lead or leads can be used as the other electrode forming a sensing pair with the indifferent electrode. The electrode is located in the plastic connector top portion of the implanted pacemaker, and may be disposed at a side of the pacemaker, when implanted, facing the interior of the patient, or facing the exterior of the patient.

Abstract: Systems and methods for non-invasive blood analysis are disclosed in which blood is illuminated at a plurality of discrete wavelengths selected from the near infrared spectrum. Measurements of the intensity of transmitted or reflected light at such wavelengths are taken, and an analysis of transmittance or reflectance ratios for various wavelengths is performed. Changes in the ratios can be correlated with specific near infrared (IR) absorption peak for the analyte which varies with concentration of the analyte (the data wavelength) and the a second (reference) wavelength being sufficiently removed from the first so that measurements of light absorption at this second wavelength are relatively insensitive to the concentration of the analyte and yet the second wavelength is sufficiently close to the first wavelength to minimize interference from scattering effects and the like.

Abstract: A defibrillator (10) is disclosed in which measured information concerning the energy delivered by the defibrillator to a meter (56) is employed to calibrate subsequent discharges by the defibrillator at the same energy level. In connection with that process, a microprocessor (70) controls the operation of a feedback loop (50), including a controlled-gain amplifier (64), level detector (66), adder (68) and energy charger (58), to adjust the voltage applied to a discharge capacitor (54) in response to the energy measured by the meter. The information can be input to the microprocessor either manually or automatically and can be used by the microprocessor in performing a piecewise linear approximation of the voltage adjustment required to deliver the desired nominal energy, or in performing a direct computation of that adjustment. This process is repeated for each of the energy levels selectively dischargeable by the defibrillator.

Abstract: An ultrasonic non-contact motion monitoring system, useful for monitoring motional activities and such activities as respiration rate and heart beat rate. Using dual ultrasonic transducers, coherent sound waves are directed toward a moving subject. The phase frequency relationship of the reflected waves are compared to the transmitted sound waves in-phase and in phase-quadrature. The derived information, containing movement activity, is either displayed locally or sent to remote station(s) for display, processing and storage.

Abstract: A sphygmomanometer including a constant rate air-bleed valve for that is coupled to a cuff for reducing the pressure in the cuff. The valve has a valve casing and a tubular member in the casing. A slit in the tubular member allows air to bleed from the cuff at the constant rate and a regulator is provided for adjusting the bleed rate.

Abstract: Electro-stimulation apparatus comprises a self-contained housing including at least one energy source, a contact end for application against the skin of a user so as to transmit a series of repetitive electrical discharges to the skin, and means for stabilizing the current and the frequency of the discharges. When the energy source has worn to such an extent that the discharge current can no longer be stabilized, the apparatus stops working and must be discarded.

Abstract: A temporary cardiac lead for establishing electrical contact between a body tissue and a pulse generator. The lead includes a flexible conductor having a proximal end and a distal end. The proximal end of the conductor is connected to the pulse generator. An electrode is connected to the distal end of the connector for establishing electrical contact with the body tissue. A helical coil is secured to the electrode for frictionally resisting the movement of the lead relative to the body tissue. The coil has a generally rectangular cross-section, for giving it an overall flat configuration, in order to improve the positioning of the coil within the myocardial tissue, to dispense with auxiliary accessories such as silicon rubber discs, and to reduce the size of the lead and to render it adequate for use in atrial and pediatric applications.

Abstract: A method of treating subretinal neovascularization (SRNV) using a fiberoptic probe to introduce laser energy transsclerally to obliterate the SRNV complex without damaging the sclera or retina.

Abstract: A bi-polar cardiac lead for transmitting electric current to the heart and/or sensing and monitoring electrical activity of the heart has elongated electrical conductors connected to a head. The lead has a first electrode mounted on the head having a helical wire connected to one conductor adapted to be turned into heart tissue. The helical wire is coated with platinum black particles which decrease electrical losses at the electrode-tissue interface. A second annular electrode having an irregular outer surface configuration is mounted on the head around the first electrode. A plug impregnated with a drug is located within a recess in the head adjacent the electrodes. The drug migrates from the plug to the stimulation site.

Abstract: Apparatus for driving a medical appliance has a single compressor for generating both the positive and the negative pressures. Positive and negative pressure valves for controlling communication with the atmosphere are connected to the outlet and inlet terminals of the compressor and the outlet and inlet terminals of the compressor are also connected to a positive pressure accumulator and a negative pressure accumulator, respectively. The apparatus has pressure sensors to sense when the pressures in the accumulators reach a set pressure. The apparatus further has a one-way valve in the positive pressure line between the compressor and the valve or in the negative pressure line between the compressor and the valve. The apparatus prohibits the positive and negative pressure valves from being open at the same time.

Abstract: Disclosed is an ultrasonic receiving apparatus for use with an ultrasonic diagnosis system, the apparatus containing digital delaying means and/or digital adding means. The delaying means provides delays of sufficiently high accuracy using a clock signal of a reasonably high repeat frequency on a reasonable scale of circuit construction, while the adding means allows for larger probe aperture.(1) The delaying means has delay circuits each offering a delay in units of the clock signal cycle, and infinitesimal delaying circuits each multiplying two signals derived from a single reception signal, one of the two signals being delayed relative to the other before the two are added.

Abstract: An apparatus for stimulating bone tissue for stimulating bone growth or treating osteoporosis by applying directly to the skin of the patient an alternating current electrical signal comprising wave forms known to simulate the piezoelectric constituents in bone. The apparatus may, by moving a switch, stimulate bone growth or treat osteoporosis, as desired. Based on low-power CMOS technology and enclosed in a moisture-resistant case shaped to fit comfortably, two astable multivibrators produce the desired waveforms. The amplitude, pulse width and pulse frequency, and the subpulse width and subpulse frequency of the waveforms are adjustable. The apparatus, preferably powered by a standard 9-volt battery, includes signal amplitude sensors and warning signals indicate an output is being produced and the battery needs to be replaced.

Abstract: An ultrasonic probe assembly in which the disposition of the scan plane of an ultrasonic transducer unit, introduced into a human body, can be selected to image a body part in different ways. The scan plane is selected by operation of a remote control unit by which the ultrasonic array is moved. The ultrasonic array is mounted to a base unit for pivotal movement relative to the base unit and is steered by the action of a cable which is controlled by the remote control unit.

Abstract: An implantable system for the treatment of obstructive sleep apnea by electrical stimulation of the musculature of the upper airway. The system employs one or more sensors to determine the onset of an apnea event. Upon sensing of the onset of an apnea event, the stimulation generator provides a signal for stimulating the muscles of the upper airway at a varying intensity wherein the intensity is gradually increased during the course of the stimulation. The signal is coupled to the muscles to be stimulated by an electrode connected to the stimulation generator by an insulated lead.

Abstract: A method and apparatus for measuring subthreshold defibrillation electrode resistance are disclosed. A known subthreshold current pulse is sourced across the electrodes, the resulting voltage is measured and the electrode resistance is calculated from these values. The calculated electrode resistance may be utilized to adjust the energy level of a defibrillation shock used to treat a detected tachyarrhythmia. In one embodiment the calculated resistance and a predetermined leading edge voltage are used to calculate and adjust the duration of the defibrillation shock. In another embodiment the calculated electrode resistance and a predetermined shock duration are used to adjust the leading edge voltage of the defibrillation shock.

Abstract: A method and apparatus for storing a representation of a cardiac signal by compressing the data using scan correlation and temporal data compression techniques. The method and apparatus sense cardiac signals when the heart is functioning in a known cardiac state, then characterize this known state by storing a temporally compressed template of time sequence samples. The method and apparatus may perform testing for multiple different cardiac states and store templates associated with each state. Subsequently when the heart is functioning in an unknown cardiac state, the method and apparatus monitor cardiac signals by temporally compressing samples and scan correlating these samples with the previously stored templates to derive correlation coefficients. These correlation coefficients are a basis for identifying and classifying cardiac signal waveforms.

Abstract: An ultrasonic diagnostic imaging system is described which enhances the presentation of flow velocity images through asymmetric persistence of visually displayed changes in fluid velocity. Preferably the asymmetric persistence employs a shorter (i.e., faster) time constant for increases in fluid velocity and a longer (i.e., slower) time constant for decreases in fluid velocity. In a preferred embodiment of the present invention, increases in fluid velocity are displayed at their rate of occurrence, and decreases in fluid velocity are displayed with a longer, user-selectable time constant. In the preferred embodiment the persistence enhancement is determined as a function of displayed image frame rate so that the persistence time constant remains fixed as a function of time despite user changes affecting the frame rate.