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Electrocardiograph Wave Detector

IP.com Disclosure Number: IPCOM000086178D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Kennedy, PJ: AUTHOR [+2]

Abstract

The electrocardiograph (EKG) has been well known for many years and normally presents a chart of one or more lines for visual interpretation. When it is desired to automate medical diagnosis and patient care, the use of the EKG presents problems due to biological deviations and variations which tend to obscure the features of interest.

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Electrocardiograph Wave Detector

The electrocardiograph (EKG) has been well known for many years and normally presents a chart of one or more lines for visual interpretation. When it is desired to automate medical diagnosis and patient care, the use of the EKG presents problems due to biological deviations and variations which tend to obscure the features of interest.

As indicated in Fig. 1, a graph of the output of an EKG will be substantially repetitive for each heart beat and each cycle will have a main pulse R bracketed by Q and S portions, and also having other small pulses such as P, T, and U. It is desired to recognize the R pulses over a normal range of heart beat frequencies and the circuit detailed in Fig. 2 has been found effective for this purpose.

In the drawing, a pair of input leads 10 and 11 of a differential amplifier 12 are attached to a patient to receive heart signals. The amplifier 12 comprises a pair of transistors 14 and 15 with individual collector loads 16 and 17 and a common emitter connection fed through a current controller 18. The input leads 10 and 11 are connected, respectively, to the bases of transistors 14 and 15. The collectors of transistors 14 and 15 are each connected through capacitors 20 or 21 to their associated amplifiers 22 and 23, which have a common output with feedback connections to each amplifier's second input. A large capacitor 24 will provide substantially full feedback at higher frequencies, whereas the AC coupl...