Showing papers on "Heartbeat published in 1992"

Fractal mechanisms in the electrophysiology of the heart

Abstract: Fractals are defined, and the fractal-like anatomy of the heart is described. The concept of the healthy heartbeat as a temporal fractal is examined at two specific levels of cardiac function: ventricular depolarization and heart rate regulation. It is suggested that complex fluctuations in healthy heart rate may be due in part to deterministic chaos in the neuroautonomic control system. Furthermore, perturbations of this control system, such as those seen in heart failure and in sudden cardiac death syndromes, may lead to a loss of complexity of heart rate dynamics. >

Computer gated positive expiratory pressure method

Abstract: The computer gated positive expiratory pressure method alters pressure in a patient breathing pathway in a respiratory ventilator during specified periods of a patient's heart cycle. Heartbeats of a patient are detected in patient cardiac cycles, and an electrical heartbeat signal is generated in response to the heartbeats. In a presently preferred embodiment, the electrical heartbeat signal is squared to amplify the signal. A variable moment following a detected heartbeat is determined, and positive ventilation pressure in the patient breathing pathway is altered commencing at the variable moment following a detected heartbeat, for a variable time interval during selected cardiac cycles.

Heart-synchronized pulsed laser system

Abstract: A heart-synchronized pulsed laser system includes a laser; means for sensing the contraction and expansion of a beating heart to be synchronized with the laser; means, responsive to the means for sensing, for generating a trigger pulse; means for positioning the leading edge of the trigger pulse during the contraction and expansion cycle of the heartbeat; means for defining the width of the trigger pulse to occur during the heartbeat cycle; and means responsive to the trigger pulse for firing the laser to strike the beating heart at the time indicated by the trigger pulse position and for the period indicated by the width of the trigger pulse.

A comparison between two methods for assessing heartbeat perception

Abstract: In this study two methods assessing heartbeat perception ability were compared. Subjects (N = 64) completed Schandry's (1981) mental tracking task and Stormer's (1988) heartbeat discrimination procedure (based on Whitehead, Drescher, Heiman, & Blackwell, 1977). In addition, subjects were tested on their ability to estimate the duration of time intervals. A high degree of correspondence was found between the two heartbeat perception tasks for the extreme groups of very good and very poor perceivers, but a low degree of correspondence emerged for the middle range of performance (overall r = .59, p less than .001). Time estimation did not correlate significantly with either heartbeat detection procedure. Blood pressure measurements taken after the Schandry task and between Stormer test blocks showed that blood pressure amplitude was elevated among good perceivers on both heartbeat detection tasks.

System and method of impedance cardiography and heartbeat determination

Abstract: Cardiac monitoring is disclosed in which thoracic impedance and EKG signals are gathered and processed for improved resolution and accuracy. EKG signals are adaptively processed by digitizing, filtering, differentiating and raising the resultant differential by a power greater than one to emphasize changes in the slope of the EKG signal. Blocks of the thus processed EKG data are analyzed to identify peak amplitude and to compare spacing between peak amplitude adaptively to more accurately identify R wave peaks. Stroke volume is determined from a thoracic impedance signal and its time derivative. Preferably, a time-frequency distribution is taken of the time derivative thoracic impedance signal after low- and high-pass filtering to identify B and X wave events in the signal which are used to determine ventricular ejection time and dz/dt min for a determination of heart stroke volume by conventional methods. Alternatively, stroke volume is determined by a new relationship between a product of a pair of impedances simultaneously sensed on opposing sides of a patient's heart at the peak of a heartbeat.

Diagnostic apparatus for measuring changes of arterial and venous blood volumes in brain with respiration signal modulation

Abstract: A diagnostic apparatus includes light sources which emit near infrared light rays of different wavelengths. The light rays are introduced into human brain to be subjected to diagnosis and the light rays transmitted through the brain are picked up. There are provided a first detector which detects occurrences of respirations of the subject and outputs a respiration signal, and a second detector which detects occurrences of heartbeats of the subject and outputs a heartbeat signal. The light transmitted through the brain is derived in synchronism with both the respiration signal and the heartbeat signal and first and second modulated light transmission signals are produced which are respectively modulated by the respiration signal and the heartbeat signal. The first and second modulated light transmission signals are separately analyzed to provide variations in concentration of oxygenated media ΔX 02 and disoxygenated media ΔX contained in venous and arterial blood of the brain, respectively. Based thereon, oxygen saturations of both venous and arterial blood flowing in the brain are separately computed and displayed in a monitor screen.

Device for measuring heartbeat rate

Abstract: A device for measuring heartbeat rate that includes a device casing or wrist strap with skin contact electrodes, and a coil receiver for receiving telemetrically transmitted heartbeat signals for displaying heartbeat data either from the receiver, or the skin contact electrodes The signals from the skin sensor are filtered, and subjected to an AGC device and pulse shaper The received signals are amplified A microcomputer, memory, and display are common to both the pulse shaped detected heartbeat signal and the amplified signal received from the transmitter

Switch circuit for setting and signaling a voltage level

Abstract: A switch circuit is disclosed which both sets the voltage at an output terminal and signals that the voltage has been set The switch circuit may be implemented with a single-pole single-throw switch A voltage drop device, connected in parallel with the switch, is used to generate the output voltage levels The switch circuit is also suitable for enabling and disabling the heartbeat signal generated by a local area network transceiver and for signaling whether the heartbeat signal has been enabled by lighting a light-emitting diode

Implantable cardioverter/defibrillator and method employing cross-phase spectrum analysis for arrhythmia detection

Abstract: A method and apparatus for detecting and reverting pathological heart rhythms of a patient are disclosed. A plurality of electrical heart rhythm signals of the patient are sensed at two different locations within the heart. The cross-phase spectra of the sensed heart rhythm signals for each heartbeat are calculated and such heart rhythms are classified based upon the information contained in the cross-phase spectra. Appropriate therapy is then delivered to the patient's heart to revert those of the heart rhythms that are classified as pathological.

The temporal locations of heartbeat sensations.

Abstract: This experiment examined individual differences in the temporal location of heartbeat sensations and the reliability of their detection. Following practice on a familiarization task in judging light-tone simultaneity, 50 subjects were studied for two sessions on a heartbeat detection task, which required judging the simultaneity of heartbeat sensations and tones presented at six intervals following the onset of ventricular contraction. Subjects inspected the heartbeat-tone intervals as frequently and for as long as desired before choosing the one in which heartbeat sensations and tones were most simultaneous. The temporal locations of heartbeat sensations in subjects classified as "good heartbeat perceivers" (n = 16) ranged from 131 and 363 ms following ventricular contraction (mean = 228 ms). Correlations between the familiarization and heartbeat detection tasks in the accuracy of simultaneity judgments and in the frequency and duration of interval inspections suggest that general perceptual abilities and strategies may underlie success in detecting heartbeat sensations.

Effects of deuterium oxide and temperature on heart rate in Drosophila melanogaster

Abstract: A non-intrusive optical technique has been developed to monitor heartbeat in late third-instar Drosophila larvae. Heartbeat in this insect is an oscillation that is not temperature compensated. Deuterium oxide lengthens the period of a number of high and low frequency oscillators and clocks in a variety of organisms. To determine whether deuterium affects heart rate, flies were raised on proteated and deuterated media and their heartbeat was monitored at four temperatures ranging from 18 to 33°C. The rate of heartbeat increased linearly with increasing temperature, and decreased with increasing concentrations of deuterium. There was a significant interaction between temperature and deuterium: the higher the concentration of deuterium oxide the less temperature-sensitive was the heart rate. Raising temperatures also increased the amount of “noise” in the rhythm: signal-to-noise ratio, which characterizes the amount of power in a rhythmic signal, decreased with increasing temperatures. Deuterium oxide had no effect on signal-to-noise ratio.

Apparatus and method of interfacing an exercise machine to a computer

Abstract: The invention interfaces a user-powered exercise machine to a personal computer, creating a dual-mode exercise and training system with new methods of pacing ones activity in order to achieve a goal. The user determines when the exercise period will end, and sets a goal. The computer constantly displays THE REQUIRED SPEED, which is the speed that will enable the user to achieve his goal. The CALCULATED FINAL OUTCOME predicts the outcome of the exercise period, assuming that the user will continue at his current speed for the remainder of the exercise period. The user always knows how fast he will have to go to reach his goal, and always knows what the outcome will be if he maintains his current speed. This allows the user to vary his speed and still maintain a regulated overall level of activity. In the STANDARD MODE, the exercise period is a period of time, and the goal is a TARGET DISTANCE. In the TRAINING MODE, the exercise period ends when the end of the course is reached, and the goal is a TARGET TIME. The invention includes a means of calculating heartbeat rate of depressing a key on the computer keyboard at a rate proportional to the user's pulse rate. The pulse data can be used to determine a goal which will produce a beneficial heartbeat rate, and the pulse data can be recorded to compare the heartbeat recovery rate from previous exercise periods. The invention can be calibrated by changing the number of exercise machine cycles required to travel one mile.

Method for displaying superimposed heartbeat waveforms

Abstract: A computer controls a video display having a display screen for displaying ECG heartbeats superimposed over one another. The ECG data is collected during Holter monitoring and stored in a memory. A plurality of successive heartbeats are written to the display with their R-waves aligned. As the next new heartbeat in chronological order is displayed the longest-displayed heartbeat is removed. The total number of heartbeats displayed therefore remains constant. The user can select the total number of heartbeats, between one and five, to be displayed at one time. In one mode, a heartbeat is added, and removed, during each screen refresh cycle. In another mode, the user can step the display in either reverse or forward chronological order one step at a time.

Method of attracting and eradicating insects comprising attracting insects to a heartbeat sound

Abstract: A method for attracting and eradicating bloodsucking insects by generating acoustic waves that simulate a human heartbeat to attract the insects to an attractant zone. An acoustic control mechanism is powered by an electrical power source and generates control signals to an acoustic output unit, such as an acoustic speaker. A sensor unit may be provided for detecting the presence of insects within the attractant zone, and a trigger mechanism used for activating an eradication mechanism in response to a signal from the sensor unit.

Baby blanket with heartbeat simulator

Abstract: The infant blanket is of the comforter type and includes therein a foam form having a cavity therein within which a heartbeat simulator rests. The simulator is preferably pressure activated and access to same is provided by means of a zipper strategically placed in one surface of the blanket.

Methods of impedance cardiography and heartbeat determination

Abstract: Thoracic impedance (22, 23) and EKG signals (25a, 25b) are processed for improved resolution and accuracy. EKG signals are adaptively processed (26, 28) by digitizing, filtering, differentiating and raising the resultant differential by a power greater than one to emphasize changes in the slope. Blocks of the processed EKG data are analyzed (30) to identify peak amplitude and to compare spacing between peak amplitudes to more accurately identify R wave peaks. Stroke volume is determined from a thoracic impedance signal and its time derivative. Preferably, a time-frequency distribution is taken of the time derivative thoracic impedance signal after low- and high-pass filtering to identify B and X wave events which are used to determine ventricular ejection time and dZ/dtmin for heart stroke volume determination by conventional methods. Alternatively, stroke volume is determined by a new relationship between a product of a pair of impedances simultaneously sensed on opposing sides of a heart at the heartbeat's peak.

Methods of impedance cardiography and heartbeat determination as well as an apparatus for implementing said methods

Abstract: not available for EP0606301Abstract of corresponding document: US5309917Cardiac monitoring is disclosed in which thoracic impedance and EKG signals are gathered and processed for improved resolution and accuracy. EKG signals are adaptively processed by digitizing, filtering, differentiating and raising the resultant differential by a power greater than one to emphasize changes in the slope of the EKG signal. Blocks of the thus processed EKG data are analyzed to identify peak amplitude and to compare spacing between peak amplitude adaptively to more accurately identify R wave peaks. Stroke volume is determined from a thoracic impedance signal and its time derivative. Preferably, a time-frequency distribution is taken of the time derivative thoracic impedance signal after low- and high-pass filtering to identify B and X wave events in the signal which are used to determine ventricular ejection time and dz/dtmin for a determination of heart stroke volume by conventional methods. Alternatively, stroke volume is determined by a new relationship between a product of a pair of impedances simultaneously sensed on opposing sides of a patient's heart at the peak of a heartbeat.

Measuring heartbeat rate

Abstract: A device for measuring heartbeat rate that includes a device casing or wrist strap with skin contact electrodes, and a coil receiver for receiving telemetrically transmitted heartbeat signals for displaying heartbeat data either from the receiver, or the skin contact electrodes. The signals from the skin sensor are filtered, and subjected to an AGC device and pulse shaper. The received signals are amplified. A microcomputer, memory, and display are common to both the pulse shaped detected heartbeat signal and the amplified signal received from the transmitter.

Ultrasonic diagnosing device

Abstract: PURPOSE:To precisely grasp the changed state of blood flow by repeating such action that after a first frame image is displayed in synchronization with a patient's heartbeat trigger signal a proper inoperative time is provided before the next frame image is displayed CONSTITUTION:An inoperative gate generating means 87 is generally composed of counters, etc, and generates the inoperative gate signals of color flow mapping and the gate signals are forcibly reset by heartbeat trigger signals from a heartbeat trigger generating means 83 Counting of transmission trigger signals output by a transmission trigger generating means 81 is started in synchronization with the final one of operating gate signals output by an operating gate generating means 84 and this counting action is stopped by the number m of times of data fed by an inoperative time calculating means 86 The period from the start to the stop of the counting is output as one inoperative gate signal and the final signal of the inoperative gate signal is returned to the operating gate generating means 84 and the next operating signal is then generated

Auxiliary blood circulation system

Abstract: PURPOSE:To give a beat to an auxiliarily circulated flow of blood, to send blood to the coronary artery, and to reduce a load on a heart function by providing an auxiliary blood circulation circuit, a heartbeat detector, and a flow rate control means for blood operation corresponding to the heartbeat detection signal of the heartbeat detector. CONSTITUTION:An auxiliary blood circulation system 1 is equipped with a blood extraction side blood tube 5, a blood delivery side blood tube 6, the auxiliary blood circulation circuit providing with a constant voltage pump 2 and an artificial lung 3, the heartbeat detector 7, and the flow rate control means 4 for blood operated corresponding to the heartbeat detection signal from the heartbeat detector 7. The flow rate of the flow of blood generated by driving the constant voltage pump 2 can be varied intermittently, which gives the beat to the flow of blood. Furthermore, since the flow rate control means 4 is operated corresponding to the heartbeat detection signal of the heartbeat detector 7, the beat in accordance with the heartbeat detection signal can be given to the flow of blood. The blood can be surely sent to the coronary artery while the auxiliary circulation system is being operated, which efficiently supplements the heat function of a patient.

Corralling atrial fibrillation with 'maze' surgery.

Abstract: drugs and electrical cardioversion fail to tame the fibrillation, the patient remains prey to, at worst, systemic thromboembolism and congestive heart failure or, at least, the fear and unpleasant symptoms associated with an irregular heartbeat. However, the open-heart Maze procedure, developed by James Cox, chief of cardiothoracic surgery at Barnes Hospital, offers such patients a better prospect. A "maze" of carefully planned sutures creates an electrical conduction route through the atrial myocardium, corralling and herding chaotic atrial impulses from the sinoatrial (SA) node to the exit point, the atrioventricular (AV) node.

System for determining hazardous substance exposure rate from concentration measurement and heart rate data

Abstract: A device for measuring a rate exposed to deleterious materials comprises a heartbeat sensor for sensing heart rates, a deleterious material sensor for sening concentrations of deleterious materials in the air, a memory for storing the conversion values for converting the heart rates into corresponding respiration rates, and an operation unit. The operation unit counts a heart rate based a heartbeat signal received from the heartbeat sensor, calculates a respiration rate corresponding to the heart rate based on a conversion value read out from the memory, and calculates a rate exposed to deleterious material per unit time based on the calculated respiration rate and a signal respresenting a concentration of the deleterious material which signal is received from the deleterious material sensor.

Physiological functional parameter sensing method and device of a living creature

Abstract: In order to be able in the case of a measurement signal (A) (e.g. impedance) which varies as a function of a physiological functional parameter (e.g. breathing) to filter out of the measurement signal (A) the signal components occurring due to another parameter (X) (e.g. heartbeats), the period (heartbeat interval) which is inversely proportional to the respective current frequency of the other parameter (X) is continuously determined, and the mean value (M1-M13) of the measurement signal (A) is continuously formed over the period determined.

Verification of seismic detection system performance using the human heartbeat

Abstract: The need for calibration and validation of seismic measurements sometimes arises during data acquisition at field locations. The authors deal with the need for verification of signature acquisition system performance resulting from anomalous data acquired during seismic testing. A series of seismic tests was planned and initiated to acquire intruder and false/nuisance alarm signatures required for a security system design. The effort also included measurements of seismic signal propagation velocity under local soil conditions, required for investigation of a seismic beam forming system for intruder tracking. Measuring and recording system performance was verified through laboratory and field tests prior to shipment of the system. A unique offshoot of the program, the use of the human heartbeat as a calibration source, and subsequent investigation of this possibility are discussed. >