Abstract: A rate-responsive cardiac pacemaker in which deceleration of the pacing rate is modulated according to recent patient activity or "work". Based on signals provided from an activity sensor in the pacemaker, the pacemaker maintains and periodically recomputes a work value corresponding to the amount of patient activity detected over time. In response to a decrease in or cessation of detected patient activity, the pacemaker reduces the pacing rate, first at a more rapid deceleration rate, then at a lower deceleration rate, and then once again at a more rapid deceleration rate. The length of time during which the pacing rate is reduced at the lower deceleration rate is modulated according to the work value maintained by the pacemaker.

Abstract: A dual chamber cardiac pacemaker incorporating a microprocessor-based controller which is programmed to automatically establish an A-V interval at a value which provides optimum cardiac function but without the need for a special sensor for measuring cardiac function is described. The microprocessor is programmed to continuously monitor heart rate and variation in heart rate and only when the patient is stable, enter a parameter adjustment loop in which the pacemaker's A-V interval is incremented in several discrete steps and for each step, the corresponding average steady-state heart rate is measured and stored. When the A-V interval incrementation process causes that interval to reach a predetermined upper limit, the pacemaker's A-V interval is set at the value that corresponds with the minimum average heart rate to thereby maximize cardiac performance.

Abstract: A passive, non-invasive, non-contacting apparatus and method for monitoring the respiration of a subject within a monitored environment is disclosed. The apparatus generally comprises a pair of sensors which detect changes in infrared energy. The first sensor detects changes in infrared energy which signifies and corresponds to changes in the monitored environments of a component to be monitored and generates a first signal. The second sensor detects changes in infrared energy which signifies reference infrared energy in the monitored environment and generates a second signal. A processing system converts the first and second signals into a third signal which signifies the concentration of the monitored component in the monitored environment. The monitored components may be CO.sub.2, H.sub.2 O or a constituent of exhaled breath such as a ketone, amino acid, insulin or pintane. In another embodiment of the invention changes in blood pH may be monitored by adding an additional sensor.

Abstract: A cardiostimulator device includes an accelerometric sensor positioned on the electrode or cathetar intended to be inserted in the cardiac mass, possibly being associated with a stimulating or sensing electrode. In this way, it is possible to regulate the frequency (and in general all the methods) of stimulation in dependence on the so-called natural heart acceleration correlated to the physical activity of the patient.

Abstract: An arrangement and method facilitates the implantation of an electrode of an endocardial or intravenous lead at an implantation site within the heart of a human. The arrangement includes a guide wire which is formed of flexible material and which may be fed along a predetermined path which includes the implantation site. The arrangement further includes a lead formed of flexible material which includes a proximal end, a distal end, and an electrode to be implanted. The lead further includes an integrally formed follower which slidingly engages the guide wire to permit the lead to be guided along the predetermined path until the electrode to be implanted resides at its implantation site. Thereafter, the guide wire is retracted along the predetermined path to cause the electrode to remain at its implantation site.

Abstract: An improved, low-cost stretchable band incorporating a conductor for disposition around the human torso or other three-dimensional object, and particularly intended for use with respiration monitoring apparatus, is disclosed.

Abstract: An apparatus for driving an intra-aorta balloon pump is comprised of an isolator having a housing in which a first chamber and a second chamber are defined by a membrane, a positive pressure source which is in fluid communication with the first chamber via a first timing valve, a negative pressure source which is in fluid communication with the first chamber via a second timing valve, a space defined between the second chamber and the intra-aorta balloon pump and containing an amount of operating fluid, a tank for storing therein the operating fluid, an inlet valve interposed between the tank and the space, an exhaust valve interposed between the space and the atmospheric pressure, a sensor for measuring the pressure in the space, and a controller to be operated in such a manner that the first timing valve and the second timing valve are opened and closed alternately in order to establish an alternate supply of the positive and negative pressures to the first chamber and each time-duration during which the fi

Abstract: Large surface area electrode for use with a power supply having a more uniform current density distribution for contacting the exposed surface of a living body having a contour. The electrode comprises a layer of flexible conductive material of a predetermined geometrical shape and having first and second surfaces. The layer is normally relatively flat and is capable of assuming contours of the skin of the body when the electrode is placed in contact with the body with the first surface of the layer engaging the exposed surface of the body. The layer of conductive material has a central portion and a surrounding ring portion. The central portion and the surrounding ring portion have outer margins with edges. A flexible carrier layer is provided which is secured to the second surface of the layer of flexible conductive material and serves to support the central portion and the said surrounding portion so that the surrounding portion is spaced from and insulated from the central portion.

Abstract: An implantable cardioverting/defibrillating pacemaker and method for treating arrhythmias of a patient's heart are disclosed. Bradycardia support pacing is initially provided at a normal standby rate, in the absence of a tachycardia. Upon detection and confirmation of a tachycardia, antitachycardia therapy in the form of antitachycardia pacing pulse therapy and/or cardioversion or defibrillation therapy is delivered to the heart. Thereafter, upon reversion of the tachycardia, bradycardia support pacing is again delivered to the heart but at a greater rate than the earlier normal standby rate and only for a predetermined time period. At the end of such time period, the bradycardia support pacing rate is returned to the normal standby rate, either directly or in decremental steps.

Abstract: A low cost, limited-function implantable medical device. The device's synchronous circuits are driven by an ultra-slow master clock signal produced without utilization of a crystal oscillator. The device is non-invasively programmable by means of an externally applied programming magnet, which is detected by a solid state magnetic sensor (MAGFET) circuit in the implanted device. The MAGFET circuit is capable of discriminating between two polarity orientations of the programming magnet, so that one polarity is associated with increasing programmable parameters and the opposite polarity is associated with decreasing programmable parameters. Upon initial placement and detection of the programming magnet, the disclosed device performs a threshold margin test comprising three asynchronous stimulating pulses at the current pulse width and pulse amplitude settings.

Abstract: A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Abstract: An electrosurgical instrument for the removal of tissue polyps and the like is disclosed. It features a bipolar pair of conductive electrodes for the cutting of tissue in which at least one electrode is moveable in relation to the other. These electrodes are mounted relative to an insulating plug, which is secured at the distal end of a tubular member. Pressure exerted on a thumb loop shifts the position of one electrode relative to the other. Upon application of RF voltage, the distance at which the electrodes are placed controls the amount of arcing which will occur between electrodes, when placed within a proper range. The electrodes are supplied with power from a standard RF energy source, controlled from a foot or hand switch. The insulating plug may further include metal traces disposed on the peripheral surface. When energized, these traces function as a bipolar pair of electrodes for effecting electrocoagulation of tissue and blood.

Abstract: A variable rate defibrillator charging circuit includes a power transformer that accepts an internal battery output and the output from an AC-to-DC converter on separate primary windings. The secondary winding of the transformer is coupled through a rectifier to a storage capacitor. The transformer operates in a fly-back mode whereby energy is discharged into the storage capacitor when the power supplies discontinue charging the transformer. After energy in the transformer is discharged into the storage capacitor, the power supplies are reactivated, recharging the transformer. The separate primary windings of the transformer provide a fast, reliable, low cost means for charging the storage capacitor with multiple power supplies. The AC power source feeding the AC-to-DC converter is detachable allowing the defibrillator to be operated remotely whereby the storage capacitor is charged solely from the internal battery.

Abstract: A novel medical device, SNOPPER--The Snoring Stopper.TM. anti-snoring mouth device, is inserted into the mouth. The device comprises a denture-like(10) apparatus for supporting electrodes(12) in such a manner that the electrodes make contact with the roof of the mouth. Electrical stimulation induces contraction of relaxed muscles, thereby preventing or stopping snoring. Electrical energy is provided to the device via wires for connection to an external stimulator(16) or via a self-contained, battery-powered, microminiturized electronic stimulator(20). Stimulation can be constant or intermittent. Wave shape, amplitutde, length, and frequency is controlled by the individual for comfort and is automatically induced via a feedback mechanism.

Abstract: A pacemaker having a hysteresis feature which permits intrinsic heart activity, controlled by the sinus node to resume optimally after pacing. The pacemaker has a programmable lower rate and upper rate, a programmable lower hysteresis rate (LRH) corresponding to a lower rate hysteresis interval (LRHI), and a programmable rate (IR) intermediate an upper pacing rate (UR) and a lower pacing rate (LR). A microprocessor measures the average rate of change M.sub.AVG in the intervals between consecutive ventricular depolarizations, and compares the last intrinsic escape interval RR.sub.N to the lower rate hysteresis interval (LRHI).If the last intrinsic escape interval RR.sub.N is longer than the lower rate hysteresis interval (LRHI), and if the value of M.sub.AVG is greater than a first preselected value SL.sub.1 but less than a second preselected value SL.sub.2, the pacemaker stimulates at the lower rate hysteresis (LRH) and thereafter gradually increases the pacing rate up to the intermediate rate (IR).

Abstract: A blood pressure monitor system, including a pulse wave detecting device detecting a pulse wave produced from an artery of a living subject, a blood pressure measuring device including a pressing device, for measuring a blood pressure of the subject by pressing a body portion of the subject with the pressing device, a relationship determining device determining a relationship between blood pressure and pulse wave magnitude, based on a pulse wave magnitude detected by the pulse wave detecting device and a blood pressure value measured by the blood pressure measuring device, a blood pressure monitor device continuously determining, according to the relationship, blood pressure values of the subject based on magnitudes of the pulse wave detected by the pulse wave detecting device, the relationship determining device updating the relationship at intervals of time, based on blood pressure values measured by the blood pressure measuring device, a blood pressure variation determining device determining a variation o

Abstract: An system for imaging an oxygen-containing animal includes an illuminating light source 10, optical filters 12, a microscope and an associated epifluorescence attachment 16, a long pass cutoff filter 8, a camera 20, a frame grabber 22, a counter timer board 24, a computer 26 and an analog monitor 28. The light from the flash lamp 10 is passed through the optical filters to remove an unwanted portion of the spectrum, and focused on a sample object 14 through the epifluorescence attachment and phosphorescence is observed through the long pass cutoff filter. The images are collected with the camera and the frame grabber is used to digitize and average frames while the timing of the flash and gating of the camera intensifier is controlled by the counter timer board. The frames are displayed on the analog monitor.

Abstract: A spirometric measurement device includes an arrangement for computation of a dynamic correction factor to compensate for temperature-related volume changes in time varying raw forced expiratory volume (FEV) data due to cooling of expired gas. The correction factor, which compensates for body-temperature-pressure-saturated (BTPS) changes, varies in time according to variation of temperature of a flow sensor. The temperature of the flow sensor is accurately established by positioning a temperature sensor downstream of the flow sensor.

Abstract: An implantable medical apparatus for stimulating a heart at a variable stimulation rate dependent on the respiratory rate, tidal volume, heart rate and stroke volume includes a measurement apparatus which measures impedance around the heart, a filter unit which splits the impedance signal into high-frequency and a low-frequency signal portions and two analyzers which respectively evaluate the signal portions and which emit the four parameter values as output signals. The product of respiratory rate times tidal volume is formed in a control apparatus. This product corresponds to respiratory minute volume, and the product of heart rate times stroke volume corresponds to cardiac output. Cardiac output is multiplied by a constant, and respiratory minute volume is subtracted from the product thus formed. The resulting different is equal to zero when blood oxygenation is optimum. The control apparatus controls the stimulation rate on the basis of the magnitude and sign of the difference.

Abstract: A pressure pulse wave transmitting sheet for being interposed between a skin surface of a living subject such as a patient and a pressure pulse wave sensor set on the skin surface in pressed contact therewith, the sensor having a press surface in which at least one pressure sensing element is provided and which is pressed against the skin surface so that the at least one pressure sensing element detects a pressure pulse wave transmitted from an artery of the subject underlying the skin surface, to the press surface via the sheet, the sheet being formed of an elastic material having a hardness substantially equal to a hardness of human being's skin.