advances in ecg data acquisition and display
DESCRIPTION
ECG/EKG is the short for electrocardiograph. It is widely accepted and non-invasive tool for cardiac investigations. Two new systems of data acquisition and display of ECG signal are discussed EMBEDDED ECG SYSTEM WITH MATLAB BASED GUIWEARABLE WIRELESS ECG SYSTEMTRANSCRIPT
CONTENT
¨ Introduction¨ Need for New Systems¨ Embedded ECG System with MATLAB-based GUI
* System Description* ECG Signal Acquisition System*Online ECG Processing software
¨ Wearable Wireless ECG System*Hardware System
*Monitoring Application for Mobile Device¨ Conclusion¨ References
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INTRODUCTION
¨ ECG/EKG is the short for electrocardiograph. It is widely accepted and non-invasive tool for cardiac investigations. Two new systems of data acquisition and display of ECG signal are discussed
1) EMBEDDED ECG SYSTEM WITH MATLAB BASED GUI
2) WEARABLE WIRELESS ECG SYSTEM
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ECG/EKG
¨ Instrument recording heart’s electrical activity
¨ ECG provides valuable information about a wide range of cardiac disorders
¨ ECG waveform consists of P, QRS and T segments
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ECG WAVEFORM
1. Atrialdepolarization
3. Ventricular
repolarization2. Ventricular depolarization
Fig. 1 ECG waveform
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NEED FOR NEW SYSTEMS
¨ Low power, cheap and high-speed features
¨ Remote monitoring of patients
¨ Automatic detection of disorders
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EMBEDDED ECG SYSTEM WITH MATLAB BASED GUI
¨ System consists of two parts
1) An accurate ECG signal acquisition system
to collect online ECG data
2) A software to provide a user-friendly
interface to the user
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System Description
Fig. 2 Block schematic of the developed system
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System Description
Fig. 3 Analog Processing Circuit for the ECG Signal
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ECG Signal Acquisition System
¨ It consists of
1) An analog signal conditioning circuit (including filter, instrumentation amplifier)
2) An ADC
3) A microcontroller
4) A TTL-RS232 level converter
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ECG Signal Acquisition System
¨ ECG signal is applied at the input of signal conditioner
¨ Output of signal conditioner is fed to ADC input, which provides 8-bit data to the microcontroller unit
¨ Microcontroller converts ADC output into a serial bit-stream for delivery to PC through serial port
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Online ECG Processing Software
¨ Starting point of ECG signal processing is accurate determination of R-peaks
¨ Algorithm is developed considering maximum possible deviations from normal ECG
¨ All the time-plane extracted features are displayed along with display plot for ECG signal
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ECG Visualisation
Fig. 4 Developed GUI with signal plots and processed ECG features
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WEARABLE WIRELESS ECG SYSTEM
¨ System comprises two parts
1) Hardware System
2) Monitoring Application for The Mobile
Phone
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System Description
Fig. 5 System Description
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Hardware System
Hardware System
Signal Acquisition
Signal Processing
Bluetooth Data
Transmission
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Hardware System: Signal Acquisition
¨ Simple Three Lead System Used
¨ Use of differential amplifier with a gain around 1000, CMMR greater than 110 db and 0.05-200 Hz bandwidth is required
¨ Filtering stage is a band pass filter to eliminate artefacts
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Hardware System: Signal Processing
¨ For analog to digital conversion, PIC16F876 microcontroller is used
¨ FPGAs is used to allow reconfigurable systems
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Hardware Systems: Bluetooth Data Transmission
¨ Bluetooth module used is the WRAP THOR 2022-1-B2B chip from BlueGiga
¨ Bluetooth module provides an API for communication through the AT commands
¨ Internal parameters of Bluetooth module optimized to get the lowest consumption mode
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Monitoring Application For Mobile Device
¨ Allows monitoring patient’s ECG in real time
¨ Mobile device used as server or client
¨ Application developed using the Java platform form for embedded devices (J2ME)
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ECG Visualisation
Fig. 6 ECG visualisation in the mobile phone
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CONCLUSION
¨ Low cost system
¨ Automatic detection of pathologies
¨ Inclusion of other biomedical signals such as EMG is possible
¨ Remote monitoring can enhance healthcare on a large scale
¨ Improvements to connect to a hospital database possible
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