Showing papers on "Heartbeat published in 1969"

Effects of Feedback and Reinforcement on the Control of Human Systolic Blood Pressure

Abstract: An automatic procedure providing information about human systolic blood pressure at each successive heartbeat under routine laboratory conditions is described. Twenty normal male subjects were given feedback of their own systolic pressure, half operantly reinforced for increasing and half reinforced for decreasing their pressure. Significant differences in pressure were obtained in a single session. The apparatus and results suggest a possible approach to the treatment of essential hypertension.

Heartbeat monitor with audio and visual outputs

Abstract: A pocket size, self-contained cardiac monitor for on-patient or central station monitoring by visible and/or audible signals related to the beat of a patient''s heart, the monitor having the features of: using its own circuitry for calibration; having a time delay to mask out spurious signals; and having circuit means to drive a monitor lamp and speaker with a minimum of power.

Cardiac pacer system

Abstract: An implanted pacer system includes a resettable oscillator for generating a train of pulses having a period slightly greater than the period of a natural heartbeat. The pulses generated in the oscillator are coupled to a pulse shaper network which transmits pulses to an electrode contacting the heart. If no natural heartbeat is sensed, the oscillator operates at its natural frequency and the shaper network transmits heartstimulating pulses to the electrodes. If a natural heartbeat is detected, the oscillator is reset and timing circuitry in the shaper network is modified so that a non-stimulating pulse is transmitted to the electrode. The non-stimulating pulses are detectable by a receiver outside the body to permit an examining physician to ascertain whether the pacer system is operative when the heart is functioning normally even though the system is noncompeting. Further, the non-stimulating pulses do not produce an artifact on an EKG machine monitoring the patient''s heartbeat, and negligible energy is dissipated in the non-stimulating pulses.

Ectopic heartbeat detector

Abstract: A critical ectopic beat detector for providing a warning that an ectopic beat is approaching a critical portion of a heartbeat including first circuit means for monitoring a heartbeat including means for providing a first signal representative of a normal portion of said heartbeat and a second signal representative of an ectopic beat, second circuit means for measuring the time relationship between said fist and second signals, and third circuit means for providing a third signal in the event said time reaches a predetermined value to thus provide a warning that said ectopic beat is approaching said critical portion of said heartbeat, including instrumentation for presetting said predetermined value into the circuit so that the equipment may be utilized with equal facility for different patients having different heartbeat patterns, and also including an arrangement for monitoring the heartbeat on a scope and placing on the scope an indication that the ectopic beat has approached within a predetermined time of said predetermined critical portion of the heartbeat so as to enable an accurate visual observation of the change in pattern of the heartbeat.

Heartbeat frequency monitor

Abstract: There is described a diagnostic system for measuring the frequency of a patient''s heartbeat which automatically protects against erroneous low readings resulting from abnormally high heartbeat frequencies. An input transducer monitors the patient''s electrocardiac signal and develops an amplified electrical signal representative thereof. A monostable multivibrator is responsive to this amplified signal to produce an output signal consisting of a series of pulses having a uniform amplitude and width and having a repetition rate representative of the heartbeat frequency. The pulse series is converted into a DC voltage, proportional to the repetition rate, by a frequency-to-voltage converter. A readout device in the form of a voltmeter is responsive to the DC voltage to provide a visual indication of the patient''s heartbeat frequency. The output signal of the multivibrator is subject to erroneous low values resulting from abnormally high heartbeat frequencies having periods shorter than the pulse width of the multivibrator. To overcome this deficiency, an additional amplifier circuit is employed which is responsive to the repetition rate of the multivibrator output signal for effecting variations in the multivibrator timing circuit to maintain its pulse width shorter than the heartbeat period regardless of variations in the patient''s heartbeat frequency. This prevents the erroneous low values in the multivibrator output signal and thereby precludes erroneous heartbeat frequency readings resulting therefrom.

Apparatus for electro-medical investigation

Abstract: A medical diagnostic apparatus for producing an audible indication of the nature of electric signals produced in the human body by the action of the heart. An audio frequency carrier wave is modulated both in frequency and in amplitude in accordance with the aforesaid applied electric signals. The level of the fundamental tone normally remains below the limit of audibility. This limit is exceeded only when an electric heartbeat signal occurs.