Abstract: A hand-held physiological stimulation and treatment signal applicator. The applicator includes a housing having a portion in which electrical controls are mounted for facilitated manipulation thereof by the user's hand embracing the housing portion in the use of the apparatus. Different types of physiological treatment signals may be provided separately or in combination from the associated power sources and controlled by the housing mounted controls. The applicator head provided for facial engagement with the patient's tissue is swivelly mounted to the end of the applicator housing for facilitated adjustment of the head to insure desired facial engagement between the head and patient's tissue. Structure is provided for providing positive grasping of the applicator housing adjacent the applicator head while preventing interference between the user's fingers and the patient's tissue adjacent the head.

Abstract: A hermetically sealed combination ceramic and metal package for electronic components of an electronic device implantable in a living body, at least some of the components being adversely affected by high temperatures. The package comprises a ceramic sleeve and a metal band having substantially the same coefficients of linear thermal expansion. An annular end face of the sleeve butts against and hermetically seals to an annular end of the metal band. A header plate carrying a substrate upon which the components are mounted and a plurality of electrical connectors closes the open end of the sleeve and is hermetically sealed to the metal band.

Abstract: A method and an apparatus for facilitating the healing of soft tissue wounds. The method includes the steps of selecting an area of tissue that is wounded, and applying therapeutic microcurrent excursions ranging from 100 to 1,000 microamperes and having a frequency of 10 to 50 hertz to the selected area of tissue. The apparatus includes a bandage containing circuitry for generating the therapeutic microcurrent excursions and a first and a second electrode coupled to the circuitry. A housing holds said first and second electrodes apart and adjacent to said selected area of tissue when the apparatus is placed over the selected area of tissue. During operation of the apparatus, an electric circuit is completed as microcurrent excursions propagate from the first electrode across the selected tissue wound to the second electrode.

Abstract: An apparatus for driving a medical appliance has a sensor for sensing a driving pressure which is an output pressure of the apparatus. The apparatus measures the rising and falling characteristics of the driving pressure by signals from the sensor. The apparatus adjusts the pressures in accordance with the rising and falling characteristics.

Abstract: A method of characterizing pregnant female myometrial activity to distinguish between myometrial activity predictive of term or preterm labor and of contractures, which method comprises: (a) sensing discrete epochs of myometrial contractility and producing signals representing said discrete epochs; (b) storing said epoch representing signals; (c) determining characteristic repetitive frequencies of said signals and thereby determining whether the myometrial activity being characterized is predictive of term or preterm labor.

Abstract: A dual chamber pacemaker with variable V-A delay based on detection of multiple criteria before lengthening the V-A delay period. Before the V-A delay period can be extended, the pacemaker must be stimulating the ventricle at a maximum ventricular rate, and an atrial event must be sensed in a relative atrial refractory period. During this interval the pacemaker would not respond to an atrial event that was sensed, but the occurrence of the event would be detected. To optimize a ventricular blanking period, in each cardiac cycle, the energy level of the atrial output pulse and the sensitivity of the ventricular sense amplifier are sampled. Based on these dynamic parameters, the duration of the ventricle blanking period is adjusted for each cycle so that a minimum ventricular blanking period can be maintained without cross-talk.

Abstract: An apparatus for monitoring intracompartmental pressures, such as intrauterine pressure, is disclosed. The apparatus comprises a catheter having a first chamber formed in the interior of the catheter tip which is in amniotic fluids communications with the fluids contained in the uterus. A second chamber is defined by a lumen of the catheter and is filled with air. The lumen extends the length of the catheter from the first chamber at the tip of the catheter to a diaphragm of a pressure transducer located at the end of the catheter. Thus, an air column is formed in the second chamber defined by the lumen. The relative volumetric cubic capacity of the first and second chambers is such that, under maximum pressures which are within expected ranges, the trapped air column prevents any liquid fluids from entering the second chamber. Also, provided is a valve which in a first or "zero" position causes both sides of the pressure transducer diaphragm to be placed at atmospheric pressure.

Abstract: A rate responsive pacer is disclosed which alters the pacer's escape interval in response to the patient's metabolic demand. Metabolic demand is determined from the patient's respiration rate which is extracted from spontaneous muscle signals.

Abstract: A method and apparatus for processing a plurality of signals provided by an array of electrodes disposed on the surface of the body further comprising a reconstruction of the electrical activity on the surface of a selected interior organ according to the plurality of array signals and a selected model of the body in the region of the interior organ and the electrode array. The reconstruction includes assumptions made according to a priori knowledge of the selected model and permits reconstruction of the electrical activity on the surface of the interior organ and can further provide practical solutions with underdetermined sets of equations. The present inventions further includes reconstruction including a power spectrum analysis of the array signals to permit detection and localizing of a predetermined physiological condition. The power spectrum analysis may further include a frequency domain analysis according to the minimum relative entropy of the measured signals.

Abstract: A catheter, which is adapted to be inserted into a body lumen, comprises a symmetrical cylindrical control handle, an elongate tubular catheter body, and a flexible catheter tip having a lumen offset from the axis of the catheter tip. The control handle comprises a housing having a piston chamber at its distal end. A piston is mounted in the piston chamber and is afforded lengthwise movement. The proximal end of the catheter body is fixedly attached to the distal end of the piston. A puller wire is attached to the housing and extends through the piston, through and coaxial with the catheter body and into the offset lumen of the catheter tip where it is attached to the wall of the catheter tip. Lengthwise movement of the piston relative to the housing results in deflection of the catheter tip.

Abstract: A method and apparatus for differentiating between arrhythmia and noise in an antiarrhythmia device. A noise detection criteria is applied to a detected signal so as to detect noise simultaneously at two different sensitivity levels. When noise is not detected on the high gain channel the low gain channel is used for detecting arrhythmias. Arrhythmia therapy is then delivered.

Abstract: A technique has been devised to pace the heart, defibrillate the heart, or ventilate the lungs of a patient using extremely low electrical power. These techniques use an internal esophageal electrode as the basic common terminal with chest electrodes positioned to direct a particular current to a particular place depending on whether pacing, defibrillation or ventilation is to be accomplished. In accordance with the present invention a particular configuration of multiple ring electrodes has been devised to facilitate these techniques.

Abstract: A cardiac pacing lead or other stimulation lead carrying a drug incorporated into a controlled release device. The lead is provided with an extendable fixation helix which is advanceable from the distal end of the lead in order to engage with the tissue to be stimulated and to maintain the distal end of the lead adjacent the tissue to be stimulated. The controlled release device is located within the fixation helix and is extended with the fixation helix when it is advanced out of the distal end of the lead. In its advanced position, the controlled release device is positioned adjacent the distal end of the lead, preferably in a position to contact the tissue to be stimulated.

Abstract: A diagnostic catheter for use in measuring cardiac output in the right ventricular chamber of a heart includes a catheter body having an outer periphery and a distal section terminating in a distal end and a proximal section terminating in a proximal end. A plurality of spaced electrodes are secured to the body outer periphery along the body distal section. A plurality of electrical leads extend in the catheter body from a respective one of the electrodes to the proximal end of the catheter body. An elongated rigid member is provided for stiffening a portion of the catheter body. One end of the rigid member is located adjacent a proximal most one of a plurality of electrodes. The rigid member so locates the plurality of electrodes as to space them away from endocardial tissue. The catheter is used with a cardiac output monitoring system. Signals from the catheter are acquired by a signal conditioning and catheter control unit and, are thereafter fed to a microcomputer.

Abstract: Disclosed are methods and apparatus for the detection of inadvertent endobronchial intubation, esophageal intubation and other potentially dangerous complications arising from invasive monitoring, endotracheal intubation and mechanical ventilation during surgery. Methods of the present invention generally require producing a mixed electrial signal comprising the combination of a first electrical signal and a second electrical signal, the first electrical signal being representative of the sounds emanating from a first region of the patients body and the second electrical signal being representative of the sounds emanating from a second region of the patients body. The mixed electrical signal is converted into a display signal, and then the display signal is monitored while reducing the contribution of said first electrical signal in said mixed signal to a value substantialy less than the contribution of said second signal in said mixed signal.

Abstract: A method of continuously monitoring cardiac output of a patient includes the step of determining a value of a cardiac output constant which is assumed to remain stable over the period of interest and is determined as a function of values of various measured parameters of the patient. These values may include thermodilution cardiac output, carbon dioxide production, arterial and mixed venous oxygen saturation and hemoglobin. Thereafter, cardiac output is continuously determined employing the calculated cardiac output constant and monitored values of carbon dioxide production and arterial and mixed venous oxygen saturation. Oxygen transport may also be monitored on a continuous basis.

Abstract: A medical electrical lead having a polyurethane outer sheath and one or more coiled metal conductors. The metal conductors are optimized for use in conjunction with a polyurethane sheath and are provided with a barrier coating of a biocompatible metal. The conductors may additionally be provided with an outer, insulative coating.

Abstract: A feedthrough connector for an implantable medical device, combines the connector function with the feedthrough function and eliminates the need for the cast epoxy connector previously used on such devices. The feedthrough connector includes a barrel assembly having open and closed ends. The open end of the assembly has an opening for receiving a slidably inserted electrical lead. The barrel assembly includes cylindrical metal conductive portions separated by cylindrical ceramic insulating portions. Spring contacts are mounted on the inside of the metal portions and are adapted to make electrical contact with the appropriate contacts of an electrical lead when the lead is inserted into the connector. The outer side of the metal portions are electrically connected to the appropriate electrical circuit within the housing, and the open end of the barrel assembly is bonded (welded) to the device housing so that the inside of the device can be hermetically sealed.

Abstract: A disposable protective cover (100) for application to an applanation tonometer head (20) of a Goldmann-type applanation tonometer (10). The disposable protective cover (100) may be bag like in contour or preferably pre-formed into a frusto-conical contour having a planar surface (102) bounded by a conical surface (104) which substantially matches the planar surface (22) and the conical surface (24) of applanation tonometer head (20). Disposable protective cover (100) includes at least one tab member (130) for use in handling tonometer cover (100) during application and removal therefrom. Protective cover (100) in general and the planar surface (102) in particular must fit tightly to applanation head (20), be optically transparent, and sufficiently thin so as not to interfere with the tonometer measurement. Protective cover (100) is releasably secured to applanation head (20) by a double-backed removable adhesive strip (140) which is located on the conical surface (24) of applanation tonometer head (20).

Abstract: A transvenous lead for defibrillation and pacing of the heart includes a single defibrillating coil electrode adapted to be introduced into the right ventricle of the heart. The coil constitutes a relatively long flexible large surface area electrode conformable to the shape of the ventricle and thereby readily disposed along the entire length of the vertricle for use in delivering defibrillating shocks. A pacing electrode at the tip of the lead is used both in stimulating the heart with pacing pulses and in sensing the response of the heart to the pulses and to shocks. The coil electrode is multi-filar, composed of a plurality of wires tightly wound side by side, each wire composed of copper-zirconium alloy wrapped with tantalum, and is flared from the diameter at its ends to a lager diameter intermediate its ends to increase the exposed surface area thereof in the ventricle.