Developed in CLEMA at the Medical Academy, Sofia, Bulgaria
The system was developed by Dr. Boris Gramatikov at the Biomedical Engineering Department (CLEMA) of the Medical Academy, Sofia, Bulgaria. It was designed to aid cardiologists in Cardiology departments and departments of internal medicine, in diagnosing complicated cases, conducting research, archiving important results, creating electronic ECG data banks etc. The system was preferred in cases when high-precision electrocardiography was needed. It was a valuable tool for computerized analysis, especially when additional interactive mode was necessary. Important features like stress-test, vectorcardiography, polar-cardiography and serial analysis gave the opportunity of adding diagnostic power to the routine examination and the standard interpretive features. Theoretical support, interaction with physicians, algorithm development, hardware and software design, debugging, system validation, production and installation supervision etc. were provided by Dr. Gramatikov, who also acted as programmer-analyst for most of the project. The system is flexible, modular, and continuously upgradable.
Technical description
Hardware. The ECG System 1222 is based on a personal computer (IBM xx86). It contains a peripheral isolated module which is controlled by a separate microprocessor. The module contains an amplifier board with 8 low noise amplifiers (special driven-right-leg floating circuit for minimizing common-mode and power-line interference), and a 12-bit data acquisition board, separated completely from the main computer by means of a high-isolation DC-DC converter and digital optocouplers (all galvanically separated, tested isolation of 4+ kV). This guarantees patient safety. Data is transferred to the PC system via the two RS 232 ports at a rate of 115 kbaud (fast optocouplers). The system is capable of real-time display of 8 unipolar leads simultaneously (RA,LA,C1-C6), or the 12 standard ECG leads in groups of 3 or 6 (real time or off-line). Click here for a block diagram of the front-end.
Software. The software is written in Forth programming language. Some modules are available also in C and Pascal. The eight unipolar leads (RA,LA,C1-C6) are used to compute the 12 standard ECG leads (I, II, III, aVR, aVL, aVF, V1-V6). The system is provided with flexible and expandable software for digital filtering (either standard 30 Hz lowpass tremor filter, or a special patented algorithm for acquisition and subtraction of powerline interference while fully preserving signal shape). Software further included waves recognition and measurement, diagnostic interpretation, for producing graphical print-outs and summary reports in different format, hard disk archival, serial comparison of ECGs etc. The computer interpretation of the ECG is printed out in plain text and has to be confirmed by the physician. The orthogonal Frank leads can be obtained be either direct VCG recording, or can be calculated from the 8 unipolar leads using Levkov's method.
In 1988 a full exercise stress-test protocol was added, increasing the system's diagnostic value. The stress-test feature included real-time digital filtering and artefact suppression, base-line-drift removal, signal averaging, parameter measurement, synchronization with a bicycle ergometer etc. Results (ST-measurements, HR etc) were presented as trends or numerically over intervals of 1-3 minutes (selectable). The stress-test option proved to be very useful for the functional diagnostics labs in cardiological clinics.
Specifications
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| Input Range |
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| Sensitivity |
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| Amplifier time constant (standard 12 lead ECG or exercise stress test) |
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| Analog-to-Digital Conversion |
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| Display resolution (minimum) |
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| Output resoultion (minimum) |
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| Operational system | DOS 3.0 and above; Windows compatible as a DOS application |
| Electrical safety | Class II, no ground connection, IEC 601, 4 kV isolation, leakage < 10 uA |
Application and further development
Using the ECG 1222, two annotated ECG data bases for device validation were developed. These data bases were widely used as a gold standard for testing the data analysis software implemented in microprocessor-based interpretive electrocardiographs.
During the period 1988-1989, 35 ECG 1222 units were produced by EMA Engineering Co, Bulgaria, under contract with the Bulgarian Ministry of Health. All systems were installed in hospitals in Sofia (11) and throughout the country (24) under Dr. Boris Gramatikov's supervision. Feedback from the hospitals was used for improvement of this system, as well as the analysis software of the microprocessor-based interpretive electrocardiographs.
The system is commercially available as the ECG-Computer 1202/1222, marketed in Bulgaria by EMA Engineering, Sofia.
In 1990-1991 a front end module for high-resolution ECG was added to the system, to enable recording og His- and late potentials.
Additionally, in 1993 a special serial interface was developed by Dr. Gramatikov, enabling a link between the ECG 1222 system and an interpretive electrocardiograph, ECG 322/332, which was being developed at the BME department. At first this served for better testing the electrocardiograph's interpretation software, using an ECG data base on the PC. Later, an option of connecting the cardiograph to a standard PC evolved. This improved the diagnostic capabilities of the electrocardiograph, enabled easy archival, and increased its commercialization potential. The inter-processor communication algorithms and PC program code (in Forth, C, Assembly languages) were developed by Dr. B. Gramatikov.
Related Publications:
Gramatikov, B. I., Lolov, V. R. Hardware support of an ECG diagnostic system based on a 16-bit personal computer. (in English) Fifth national conference on biomedical physics and engineering with international participation. Sofia, 14-16 October 1988. In conference Abstracts, pp.11-12.
Lolov, V.R., Gramatikov, B. I., Daskalov, I. K. A computer system for real-time processing of multiple-lead exercise ECG. (in English) Fifth National Conference on biomedical Physics and Engineering with International participation. Sofia, 14-16 October 1988. In conference Abstracts, pp.13-14.
Gramatikov,B., Lolov,V. Acquisition and Processing of ECG signals using a personal computer. (Bulg.) Third National Congress in Cardiology. Sofia, 23-25 Oct. 1987; In Abstracts, Abstr. No. 9.
