Abstract: A pair of defibrillation patch electrodes is adapted for close fitting placement over the ventricles of the heart, either epicardially or pericardially. One of the patches is contoured to fit over the right ventricle, and the other is contoured to fit over the left ventricle in spaced relationship to the first patch to form a substantially uniform gap between confronting borders of the two. The gap is sufficiently wide to avoid the shunting of current between edges of the patches upon delivery of defibrillation shocks, as well as to accommodate the ventricular septum and the major coronary arteries therein. The size and shape of the patches is such that they encompass most of the ventricular myocardium within and between their borders, to establish a nearly uniform potential gradient field throughout the entire ventricular mass when a defibrillation shock is delivered to the electrodes. Flat versions of the two electrodes provide ease of manufacture.

Abstract: A magnetic induction hearing aid where the microphone, the amplifying electronics, the battery and a coil are contained in a single housing which is located deep in the ear canal. A magnet is attached to portions of the middle ear by means of a malleus clip or by implantation between the tympanic membrane and the malleus. The magnet is vibrated by interaction with the magnetic field produced by the coil. Two amplifier designs are disclosed for use with different levels of hearing loss. The magnet can be coated with hydroxyapatite for permanent attachment to the body. The magnet is coated with hydroxyapatite by an ion implantation process, a plasma spraying technique or a method of applying the hydroxyapatite while a precoating polymeric material has not fully solidified.

Abstract: A device for use in conjunction with a pulse generator is disclosed which provides a variable pulsing rate in response to short term variations in arterial blood pressure, like the baroreceptor system of the healthy body's cardiovascular system. The system utilizes a pressure transducer implanted together with the pacemaker, the transducer is preferably located on the proximal axillary artery. The system features quick response based on physiological need, and also includes a reset feature which maintains a normal resting heart rate despite long term changes in blood pressure.

Abstract: An atrial tracking dual-chamber pacemaker and method of use for reducing the risk of initiating a pacer mediated tachycardia (PMT), and breaking such a PMT if once started. The pacemaker includes means for sensing a premature ventricular contraction (PVC). The pacemaker operates in a conventional manner unless a PVC is sensed. If a PVC is sensed, in accordance with one embodiment, an extended atrial refractory period is triggered in an attempt to block any retrograde atrial events resulting from the PVC. This is followed by an atrial alert time window. After a prescribed A-V delay subsequent to the timing out or other termination of the atrial alert time window, a ventricular stimulation pulse is generated, unless prior ventricular activity is sensed that inhibits such ventricular stimulation pulse.

Abstract: A protection circuit for a defibrillator that prevents a defibrillator pulse from being generated if the impedance between the defibrillator's electrode leads is not characteristic of the impedance between a pair of defibrillator electrodes properly connected to the defibrillator. The impedance measuring circuit applies a current to the electrode leads and the resulting voltage is measured to provide an indication of the electrode's impedance. The current is applied between the electrodes at about 33 kHz to approximate the impedance between a pair of defibrillator electrodes during a defibrillation pulse. The output of the measurement circuit is converted to an 8 bit word by an analog-to-digital converter and read by a microprocessor which compares the measured impedance to various impedance values in order to either generate an enable signal for the defibrillator or display messages indicative of open or short circuited electrode leads or a patient monitoring electrode connected to the electrode leads.

Abstract: An interference resistant biomedical transducer for monitoring the acoustic output of a patient's cardiac or respiratory system which provides a high degree of rejection of acoustic noise and spurious electromagnetic signals. The transducer comprises a piezoelectric diaphragm assembly having electrodes which produce a differential output signal. The transducer housing includes a massive metal disc and a compliant handle which provide a mechanical filter to remove undesired signals such as those related to motion of the patient and ambient acoustic noise.

Abstract: A device for anesthetizing a patient (12) during normally painful medical procedures, such as various dental treatments, performed in the area of the patient's jaw and mouth regions. A TENS apparatus (10) having a hand control device (34) comprises the apparatus invention and is employed in practicing the method. The apparatus includes a slide control bar (36) which can be operated by the patient (12) to vary the amount of current being generated by the TENS apparatus (10). The attending dentist can utilize adjustable stops (38) for regulating the range of current flow which the patient (12) can induce. Further, the apparatus (10) employs uniquely designed electrodes (18, 18') for attachment to the hand (20) and face (22), respectively, of the patient (12). The facially applied electrode (18') is affixed externally to afford an accessible work path to the attending dentist.

Abstract: A tubular device for the treatment of hollow organs is flexibly arranged and comprises a coating of silver. This coating is connected to a current source via connecting wires. Particularly, the tubular device is used for the treatment of the esophagus, and by the irritation caused by the electric current it is to effect an inflammation of the esophagus wall and thus a thickening of the latter so as to reduce the danger of hemorraghes of varicose veins within the esophagus or to prevent the hemorraghes. The tubular device is expansible in order to secure a close abutment of the silver coating against the mucous membrane of the esophagus.

Abstract: The output or outputs of the subcutaneously implanted pulse generator of a cardiac pacemaker are accessible by introducing a cannula or the wire of a stylet through the skin and thereupon through a silicone membrane which is implanted beneath the skin and surrounds a portion of a chamber which contains the output or outputs or affords access to the output or outputs through a conduit or conductor. The cannula or the wire of the sylet can be used to test the pulse generator, the lead or leads and/or the connection or connections between the lead or leads and the pulse generator as well as to admit medicaments and/or to facilitate or carry out adjustments or repairs.

Abstract: A water-proof device for a transmitter is disclosed which comprises a plurality of water-proof electrodes attached to the surface of a man for deriving minute electrocardiogram signals. A water-proof plug receives a plurality of electrode leads and, a connector for connects the leads to, a transmitter. The transmitter and connector are accommodated in a sealed water-proof sack.

Abstract: Having prospectively ascertained a patient's transthoracic resistance upon application of a low amplitude exploration current via the defibrillator electrodes, the capacitor of the defibrillator is charged sufficiently for delivery of a minimal peak current, e.g., 25 amps, preselected by the operator as appropriate for attaining defibrillation, and the capacitor is discharged to effect the defibrillation.

Abstract: The stimulation frequency of a heart pacemaker is controlled dependent on a signal representative of the blood oxygen content of the patient. The blood oxygen dependent signal is generated by a blood oxygen sensor. A temperature sensor generates a separate signal dependent on blood temperature. The blood oxygen and blood temperature signals are combined such that the blood oxygen signal is lowered, i.e., the value thereof is reduced, in ranges of higher physical load indicated by an increase in the temperature dependent signal. The combined signal is used to control the stimulation frequency of a heart pacemaker so that the stimulation frequency is increased, if blood oxygen saturation is decreasing and/or blood temperature is increasing.

Abstract: A heart pacemaker electrode for stimulating and detecting heart voltages, has an electrode head at the distal, heart-proximate end, which functions to both stimulate the heart by supplying pulses thereto, and to sense heart activity. The surface of the electrode head is divided into portions which, although electrically connected, exhibit different impedances. Once portion has a lower impedance, which primarily functions for stimulating the heart, and the other portion has a higher impedance which functions in combination with the portion of lower impedance during sensing. The electrode head thus in totality exhibits a low impedance for stimulating the heart, permitting a high current density to be achieved, while exhibiting an overall high impedance for sensing.

Abstract: A heart pacemaker has a pulse generator and circuitry for measuring a respiration signal of the user and a control unit for controlling the pulse generator by changing the pulse repetition rate dependent on the respiration signal. A heart action detector is provided for acquiring heart action signals and the respiration signal measuring circuitry includes detectors for measuring the amplitude fluctuations in the heart action signal and supplying those fluctuations to the control unit.

Abstract: An audio-visual EKG monitoring system that segments components of the patient's EKG waveform and synthesizes a plurality of audio driving signals, each representing peak values of the segmented components, and also derives similar peak value signals for driving a CRT bar graph microprocessor.

Abstract: A pulse rate monitor comprises first and second units coupled by a cable. The first unit has a microwave ocillator that provides a pulsating DC signal in accordance with the pulse rate to the second unit which amplifies the signal. Since the first unit does not comprise microwave components other than the oscillator, it can be miniturized. The second unit also supplies power to the first unit.

Abstract: A combination device are provided for a microcomputerized and enhanced type of external counterpulsation and extrathoracic cardiac massage apparatus. In addition to balloons for the 4 limbs, the device also comprises a pair of lower-abdomen-buttock balloons and a chest balloon. It is controlled by microcomputer process. The various sets of balloons are sequentially inflated from the distal portion to the proximal portion during the diastolic period of the heart beat. The pressure is applied from the distal to the proximal portion gradually onto the 4 limbs, lower abdomen buttock and lower portion of the sternum. At the beginning of the cardiac systole all of the balloons deflate simultaneously. The cycle is then repeated. This device used for the treatment of diseases of the heart, the brain, the kidneys, the isohemic disease of the retina and the peripheral vascular disease with apparent curative effect.

Abstract: A dual chamber cardiac pacemaker is programmable for either unipolar or bipolar pacing of the atrium or the ventricle, independently of the pacing mode for the other chamber. Transistor switches are utilized for selectively connecting the various anodic electrodes to ground such that one of those electrodes is grounded at all times and isolation is maintained from circuit paths for non-selected modes. Switch control is effected using signals having the highest voltage level of proper polarity in the system, to assure maintenance of the selected switch states despite possible random voltages arising from external influences. Cumulative buildup of charge on coupling capacitors is prevented by selectively and actively discharging them after the respective chamber is paced.

Abstract: When the heart is in ventricular fibrillation, the heart cells that stimulate the heart muscles produce rapid repetitive excitation without coordinated contraction of the ventricle. There is no effective simultaneous action to make the heart beat in a rhythmic fashion. A defibrillator delivers to the heart cells and muscles, enough voltage to override the erratic voltages in the heart (called repolarization) so they can rearrange themselves with order. The heart can then start over to deliver a regular rhythm.In accordance with the present invention, two small intimately located electrodes, one in the lower esophagus where it is intimate to the posterior section of the heart and the other small electrode on the chest over the sternum where it is close to the anterior portion of the heart, provide a precise electrical path between the two electrodes.

Abstract: Myocardial electrical stability is assessed by sampling an ECG waveform at corresponding fiducial locations for a plurality of beats and creating a scatter plot of the i.sup.th sample versus the (i- 1)th sample. A parameter .lambda. is determined which minimizes the sum of the total distances of the points of the scatter plot to an equation x(i)= 4.lambda.x(i- 1)[ 1-x(i- 1)]. The value of the parameter .lambda. is related to the electrical stability of the heart.