Precordial electrocardiographic map using the IBM-Bonner program

Computer Programs in Biomedicine 16 (1982) 91-96

91

Elsevier

Precordial electrocardiographic map using the IBM-Bonner program O s a m u N a k a g a k i , Yoshiaki Nose, H i r o s h i Y a n o and M o t o o m i N a k a m u r a Information Science Laboratory for Biomedicine and Cardiovascular Clinic, Kyushu University' Hospital, Fukuoka 812, Japan

The precordial electrocardiographic map may be useful for non-invasive assessment of the extent of the acutely infarcted myocardium. Rapid and serial precordial electrocardiographic maps also may be useful to evaluate the effects of intervensions of drugs and efforts on the ischemic myocardium. In this study, the I B M - B o n n e r program was applied to produce a system for the precordial electrocardiographic map. Six electrodes at one intercostal space were moved in parallel from the second to the seventh intercostal space. Thus electrocardiograms (ECGs) could be recorded from 36 precordial sites, 6 x 6 matrix, and analyzed using the I B M - B o n n e r program. The measured values of the ECG waveform make feasible the automatic procurement of the precordial electrocardiographic map. Our mapping program can be used readily and anywhere the l B M - B o n n e r program is in use. Precordial electrocardiographic map

I B M - B o n n e r program

1. I N T R O D U C T I O N The prognosis of acute myocardial infarction is largely dependent on the extent of infarction and various interventions reducing infarct size have been attempted. Since the precordial isopotential ST-map reflects the electric current of myocardial injury, a simple demonstration as a map of the area demonstrating ST segment may reflect the extent of acute myocardial infarction [1-7]. However, it is time consuming to produce manually the precordial electrocardiographic map. Therefore, software [ 1-11] for the body-surface electrocardiographic map was designed individually, in various groups. The present study was an attempt to produce a system for the precordial electrocardiographic map using the I B M - B o n n e r program [12-141.

2. M E T H O D S Our system for the precordial electrocardiographic map is shown in fig. 1. Six conventional 0010-468X/83/$03.00 © 1983 Elsevier Science Publishers B.V.

electrodes (Marquette 5608-003) at one intercostal space were moved in parallel from the second to the seventh intercostal space. Six ECGs were recorded simultaneously as V1-V6 lead of the standard 12-lead ECG. Thus ECGs could be recorded from 36 precordial sites in 6 x 6 matrix. When the precordial electrocardiographic map was required serially in a short interval, 36 disposal electrodes (3M Red Dot monitoring electrode) were attached to the precordial surface, instead of the usual conventional electrodes. A junction box was prepared in this case to connect precordial electrodes with V l - V 6 electrode cables of the electrocardiograph (Marquette MAC- 1). ECG analog signals were converted into FM and transmitted to the computer room by the public telephone network. The transmitted signal was demodulated by a FM d e m o d u l a t o r (Marquette 6100) and converted to digital data by a process computer (IBM system 7). The digital data was instantly transferred to a multipurpose computer (IBM 4341) and analyzed by the

92

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L, Fig. 1. Schema of the precordial electrocardiographic map system. Abbreviations: 3CH ECG CART, 3 channel electrocardiograph (Marquette MAC-l); I/F, interface (Marquette 6100); TEL, telephone network; RHYTHM & COMPARISON FILE, measured values of the ECG waveformby the IBM-Bonner program; MAP, the precordial electrocardiographicmap.

I B M - B o n n e r program (version 2). This program enables pattern recognition and measurement of both potentials and intervals (fig. 2). The I B M - B o n n e r program provides the pattern recognition data ( R H Y T H M FILE) and the measurement data ( C O M P A R I S O N FILE). Our newly developed mapping program enables procurement of a 6 × 6 table of potentials from R H Y T H M F I L E and C O M P A R I S O N FILE, as shown in fig. 3. A 64 × 64 table of potentials is made by the interpolation technique from the 6 × 6 table, and printed graphically. Every value measured by the I B M - B o n n e t program can be displayed in a shading map and a contour map. For example, Q-map, R-map, ST-map and QRS area-map are available. Our mapping program is coded by P L / I . The storage requirements is 16 kilobytes. The parameters required for a map are input by a few punch cards, such as size, step and kind of the map.

3. RESULTS

A typical example of ST-map in the case of acute anterior myocardial infarction is shown in fig. 4. This patient was admitted to coronary care unit with severe chest pain, serial E C G changes and serum enzyme elevation. A repeat attack occurred on the 4th hospital day and there was a parallel expansion of the ST elevation. Our system required 5 min and 1.5 min to record the standard 12-lead E C G 6 times, to analyze ECGs and to print the precordial electrocardiographic map, respectively. We could serially obtain precordial electrocardiographic maps at 5 min intervals at the shortest to evaluate the effects of intervensions of drugs and efforts on the ischemic myocardium [11], when 36 disposable electrodes were used instead of conventional electrodes.

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NORMAL SINUS RHYTHM, RATE 73 PLUS FIRST DEGREE A-V BLOCK

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M A I ~ D LEFT AXIS DEVIATION, PROBABLE LEFT ANTERIOR FASCICULAR BLOCK (UNIFASCICULAR) QRS ANGLE IS BE~4EEN -60 AND -120 DEGREES QRS WIDTH IS LESS THkN 180 MS CONSISTENT WITH ANTERIOR INFARCTION THERE IS A QS PATTERN IN ALL OF LEADS V1 THROUGH V4 (TYPE I)

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INFARCTION PROBABLY ACUTE J IS ELEVATED MORE TKAN .2 MV IN V1 AND V2 OH V2 AND V3, WITH ANTEROSEPTAL INFARCTION

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INTERVALS IN MS QRS Q-T T 113 404 200

FRONTAL pLANE ANGLES IN DEGREES QRS p T J QRST -66 59 109 NONE -64

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QRS Q 0.0 0.0 0.0 -i.3 -0.9 0.0 ~16.8 -25.2 -21.9 -17.1 0.0 0.0

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SP 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

J 0.5 0,0 -0.4 -0.3 0.3 -0.i 1.2 2.3 2,6 2,4 1.0 0,i

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Fig. 2. A interpretation report of th~ IBM-Bonnet program.

4. D I S C U S S I O N An elevation of ST segment is regarded as an index of acute myocardial injury [1-7]. The time course of ST deviation and mechanisms in cases of acute myocardial infarction are still poorly understood. The precordial electrocardiographic map reflects the myocardial action potential. Therefore, the distribution of the electrical course in the heart can assumedly be estimated using the precordial electrocardiographic map. The precordial electrocardiographic map should enable assessment of the extent of the acutely infarcted myocardium [2]. In [1511 the precordial electrocardiographic map was obtained from patients with old anterior myocardial infarction. The extent of abnormal Q,

Fig. 3. General flow of our mapping system. The IBM-Bonner program analyzes A-D converted ECG data and provides the data of pattern recognitions and measurementsin COMPARISON FILE and RHYTHM FILE, respectively. Our newly developed mapping program uses these two files to print the precordial electrocardiographicmap.

R potentials was correlated with both the ejection fraction measured by left ventriculography and the area of perfusion defect in 201TI scintigraphy. These results indicate that the precordial electrocardiographic map is useful for non-invasive evaluation of the clinical status of patients with an anterior myocardial infarction. For the automated display of the precordial electrocardiographic map, an equipment is needed to measure the potentials of the E C G waveform. Software [1-11] has been developed for this purpose. Luxton et al. [4] developed a software for ST-map and monitored the rapid changes of a short duration, in cases of acute myocardial infarction. Harumi and Musha [8], Yajima et al. [9] and T o y a m a et al. [10] also developed a specially designed computer-display system, which could display the body surface electrocardiographic map on a C R T display, in real time. Our system is characterized by using a commercially available program. Thererfore, we need not develop a software for measuring the potentials of the ECG waveform and our mapping program can be used readily and

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Fig. 4. ST-map of a patient with acute anterior myocardial infarction. The shading displays are printed according to ST elevation in increments of 0.1 mV ( < 0.09, 0.10-0.19, 0.20-0.29, 0.30-0.39, 0.40-0.49, >_ 0.5). A repeat attack occurred on the 4th hospital day and there was a parallel expansion of the ST elevation.

anywhere the I B M - B o n n e r program is in use. In addition, the precordial electrocardiographic map can be obtained from a patient even in a distant hospital, because ECGs are transmitted via the public telephone network in this system. On the other hand, this system cannot record ECGs simultaneously from 36 sites of precordial surface.

ACKNOWLEDGEMENTS We thank Ms. M. Ohara for comments on the manuscript. This work was supported, in part, by grants no. 57870067, 287084 and 220906 from the Ministry of Education, Japan.

REFERENCES

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95 [4] M.R. Luxton. D.C. Russell, A. Murray, D. Williamson, J.M.M. Neilson and M.F. Oliver, Precordial ST segment elevation: New technique for continuous recording and analysis, Brit. Heart J. 39 (1977) 493. [5] J.E. Muller, P.R. Maroko and E. Brawnwald, Precordial electrocardiographic mapping: A technique to assess the efficacy of interventions designed to limit infarct size, Circulation 57 (1978) I. [6] M,S. Spach, R.C. Barr, A. Walston, R.B. Warren and S.B. Edwards, Body surface low-level potentials during ventricular reporarization with analysis of the ST segment, Variability in normal subjects, Circulation 59 (1979) 822. [7] D.M. Mirvis, Body surface distributions of repolarization potentials after acute myocardial infarction, II. Relationship between isopotential mapping and ST-segment potential summation methods, Circulation 63 (1981) 623. [8] K. Harumi and T. Musha, Dynamic color display of body surface potential mapping (abstr.), Jap. Circ. J. 42 (1978) 748. [91 K. Yajima, H. Matsuo, H. Tanaka, K. Nakayama, S. Kinoshita and T. Furukawa, The clinical experience on the realtime display system of electrocardiographic mapping, Proc. Medinfo '80 (1980) 1126.

[101 J. Toyama, O, Tabata, M. Okajima and K. Yamada, Microcomputer processing system for body surface isopotential map and epicardial isochron-map, Proc. Medinfo '80 (1980) 259. [11] K. Fox, A. Selwyn and J. Shillingfold, Precordial electrocardiographic mapping after exercise in the diagnosis of coronary artery disease, Am. J. Cardiol, 43 (1979) 541. [12] 1BM Health Care Support/Electrocardiogram (ECG) Analysis Program Version 2 Physician's Guide, GH201935-0. [13] R.E. Bonnet, L. Crevasse, M.I. Ferrer and J.C. Greenfield, A new computer program for analysis of scalar electrocardiograms, Comput. Biomed. Res. 5 (1972) 629. [14] R.E. Bonnet, L. Crevasse, M.I. Ferret and J.C. Greenfield, A new computer program for comparative analysis of serial scalar electrocardiograms: Description and performance of the 1976 IBM program, Comput. Biomed. Res. 11 (1978) 103. [15] H. Yano, T. Tajimi, Y. Nose, O. Nakagaki, A. Mitsutake, H. Kikuchi and M. Nakamura, The precordial isopotential map: Relation to ejection fraction and 2°1T1 myocardial scintingram, Sougou Rinshou (in Japanese) 29 (1980) 2637.