Abstract: The invention relates to a supporting cushion intended for aligning or positioning the RF-coils of a magnetic resonance imaging apparatus and a patient, which cushion can serve as a part of the RF-coil and which is capable of providing a support for the RF-coil and the patient in accordance with the anatomy of an individual patient. Air is pumped in the cushion for giving the supporting cushion a desired thickness. The cushion is placed against the RF-coil in a manner that, by pumping air therein, said cushion presses the soft and yielding RF-coil against the patient. The cushion can be used e.g. in back and neck coils. The cushion can also be fitted between a patient's supporting rest and a patient in a manner that a section of the patient to be imaged is immobilized for the duration of imaging. For example, the head can be supported or braced this way by fitting the cushion between the head and a head rest.

Abstract: A tissue compensation system and method for making a tissue compensator utilizes a plurality of elongate rods, one end of which contact the treatment surface on the patient, and the other end of which contact and deform a flexible membrane containing a quantity of a material substantially equivalent to tissue of the patient.

Abstract: A swinging movement in an impact sport activity, such as golf, tennis, baseball or the like, can be monitored to analyze the skill of the player by a biofeedback mechanism which measures electrical impulses created by activated nerves as muscles tense. The mechanism includes a band adapted to be placed about an arm and/or leg of the player, the band includes a pair of electrodes adapted to contact the muscle, differential amplifier means accepting the electrical voltage from the muscle, means for measuring the amplified voltage, and reporting means affording an indication of the results of the swing, such recorder including a sound emitting device, or a transmitter and computer, recording device, or printer. Preferably, the mechanism also includes a device for signalling the point of impact with an object.

Abstract: A method for determining a dominant heart rate from a series of beat triggers representative of a mixed series of normal heart beats and non-arrhythmic activities, with the beat triggers being determined at a specific sampling rate defining sample intervals, comprising the steps of: framing a window to include a portion of the series of beat triggers and to be beat-aligned with a first beat trigger and a last beat trigger, the window thereby defining a plurality of trigger intervals for respective adjacent beat triggers, with each trigger interval containing a plurality of the sample intervals existing between the respective adjacent beat triggers; summing the windowed sample intervals; for each of the trigger intervals, computing a weight factor based upon the ratio of the summed windowed sample intervals to the number of sample intervals within that trigger interval; grouping the trigger intervals according to the weight factors; computing the percentage of the window that each group of weight factors const

Abstract: A pressure sensing lead, wherein a hollow needle extending from the distal end of the lead is coupled to a pressure transducer. The hollow needle may be coiled and adapted to be screwed into human tissue, for example through the ventricular septum from the right ventricle into the left ventricle of a patient's heart, or through the wall of the heart into the pericardial sac. Alternatively, the hollow needle may be straight and a separate coiled needle mounted around the straight needle may be provided to affix the lead to body tissue. Pressure gradients are communicated from the tip of the hollow needle to its base and applied to the pressure sensor, allowing, for example, left ventricular pressure measurements to be taken from the right ventricle or pericardial sac pressure measurements to be taken from within the heart without the necessity of the pressure sensor itself passing through the heart wall.

Abstract: First and second carrier signals, distinguishable by phase, are respectively applied to infrared and red energy emitters. A detector receives the sum of the energy after modulation at the infrared and red wavelengths. The signal received by the detector is then demultiplexed into its original first and second components, thereby allowing determining of both the infrared and red modulation components. The first and second carrier signals may comprise time-varying periodic signals with identical frequency and frequency spectra, such as a pair of sine waves which are indistinguishable except by phase and amplitude. A 90.degree. phase difference is preferred, but any phase other than 0 or an integer multiple of 180.degree. is workable. A carrier frequency which avoids excessive interference from ambient light is preferred.

Abstract: An implantable atrial defibrillator and method provides cardioverting electrical energy to the atria of a human heart in need of cardioversion. The atrial defibrillator includes a first detector for detecting R waves of the heart, a second detector for detecting T waves of the heart, and a third detector for detecting atrial activity of the heart. An atrial fibrillation detector is responsive to the third detector for determining when the atria of the heart are in need of cardioversion. A cardioverting stage applies the cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion, after the second detector detects a T wave, and in timed relation to an R wave detected by the first detector after the detected T wave is completed.

Abstract: A device for reducing power consumption in medical electrical equipment, implantable in the human body, having a sensor, which includes a sensor element and sensor electronic circuitry for sensing a parameter relevant to control of the equipment's in vivo operation, also has a comparator which compares the sensor element's output signal to a predesignated threshold value and switches the sensor electronic circuitry from a passive mode with low power consumption to an active mode with heavier power consumption or vice-versa, depending on the magnitude of the sensor element's signal in relation to the threshold value.

Abstract: The present invention relates to a method for detecting the onset of atherosclerosis and for detecting the degree of atherosclerosis. Accordingly, one aspect of the present invention correlates data obtained from arteries having a measured amount of stenosis with actual arterial data (blood volume change vs. cuff pressure) obtained from a patient which is converted into data relating to the patient's arterial peak compliance. Another aspect of the present invention detects the onset and the degree of atherosclerosis by classifying the shape of a curve obtained by relating arterial blood volume change with cuff pressure. Two devices can be used, an electrical impedance plethysmograph and a volume plethysmograph.

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: An implantable medical device, such as a heart pacemaker, or defibrillator, has a welded capsule housing which is filled with a gas mixture containing helium, the helium permitting the detection of leaks in the capsule housing. To improve the electrical insulating properties, the remaining gas of the mixture is selected from a group of gases having electrically insulating properties, such as nitrogen, sulfur hexafluoride, carbon dioxide, or halogenated hydrocarbons.

Abstract: A telemetry system and method of monitoring cardiac activity or providing therapy to the heart for an implantable cardiac device. The system includes a receiver and a transmitter in an external programmer and a receiver section and transmitter section in the cardiac device. The receiver section and the transmitter section of the cardiac device generally remain in a de-energized state. The receiver section is energized at spaced apart time intervals to detect an initiation signal transmitted by the external programmer. If the initiation signal is detected, the receiver section and the transmitter section of the cardiac device are fully activated. The external programmer includes a signal strength indicating means for providing an indication of received signal strength which the user can use to position the receiver and transmitter in the external programmer for optimum received signal strength. An antenna is disposed in the header of the implanted device to facilitate communication at high speed.

Abstract: Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart.

Abstract: A noninvasive apparatus for treating living tissue and cells by means of a pulsed electromagnetic field, and particularly suitable for bone growth stimulation. A treatment coil is noninvasively mounted in proximity to an afflicted body part to be treated, and an electronic generator coupled to said treatment coil generates pulses having a positive pulse portion 200 to 250 microseconds in duration and a negative pulse portion having a duration less than approximately 50 microseconds, the pulses further characterized by a smooth transition at least from the leading edge to a relatively flat top segment. High-frequency content is substantially reduced, particularly at frequencies above 200 kHz.

Abstract: A method of measuring blood pressure, and an automatic sphygmomanometer for implementing this method, whereby an appropriate value of cuff inflation is achieved which is dependent upon the systolic blood pressure of a patient. Pulse waves are extracted from cuff pressure obtained through a pressure detector during inflation of the cuff, and the rate of change in the amplitude of the pulse waves is obtained by a control unit. When the rate of change obtained has exceeded a predetermined threshold value, it is judged that the internal cuff pressure has surpassed the patient's systolic blood pressure. In response, inflation of the cuff by means of a pump is terminated.

Abstract: A random signal generator outputs a random noise signal to a band pass filter which selectively passes frequency components in the frequency range of a desired brain wave from a subject. The output of the band pass filter is supplied to an automatic level controller. The automatic level controller sets the output of band pass filter to a predetermined amplitude. Then, the output of the automatic level controller is fed to a stimulating light generator, which converts the output of the automatic level controller into a light signal for stimulating the subject in order to induce the desired brain wave from the subject. The light signal is then emitted into the subject's eyes.

Abstract: An electronic blood pressure meter capable of performing a proper automatic pressuring operation according to a blood pressure of a subject and measuring the blood pressure rapidly with accuracy.

Abstract: A surgical method for arthroscopic repair or replacement of the anterior cruciate ligament is disclosed. A preferred embodiment of the method generally includes forming osseous tunnels in the tibia and femur, opening into the intercondylar region. A patellar tendon graft is harvested from the knee, having bone plugs naturally attached to each end. The graft is secured in the osseous tunnels by an interference fit with a bone screw inserted between the tunnel walls and the bone plugs. Specialized instrumentation for performing the method steps is also disclosed. Such instrumentation includes: a combination drill for cutting an osseous tunnel and harvesting a bone core, an intercondylar guide for locating a pilot hole on the femoral condyle, single-fluted and multi-fluted hand and power reamers for forming an osseous tunnel, and a work station for facilitating preparatory steps performed on graft material.

Abstract: An apparatus and method for regulating the growth of living tissue are provided. The apparatus includes a deformable magnetic field generator and a magnetic field detector for producing a controlled, fluctuating, directionally oriented magnetic field parallel to a predetermined axis projecting through the target tissue. The deformable magnetic field generator includes a pair of field coils embedded in a flexible material which allows the field coils to be plastically deformed to fit the contour of a body region such as a patient's limb. The field detector samples the magnetic flux density along the predetermined access and provides a signal to a microprocessor which determines the average value of the flux density. The applied magnetic field is oscillated at predetermined frequencies to maintain a preselected ratio of frequency to average flux density.

Abstract: Methods and apparatus for the repair of sliding hiatal hernias through laparoscopic techniques comprising a tubular sleeve; a conically shaped guide with an essentially pointed forward end positionable within the sleeve; a prosthesis coupled to the guide; and means for securing the prosthesis around the esophagus of a patient immediately beneath the patient's diaphragm whereby the prosthesis assumes a generally torus shape. The prosthesis may be pre-inflated and wherein the sleeve is axially splitable after the initiation of insertion of the guide. The prosthesis may be inflatable and further including a hose to inflate the prosthesis after positioning.