Reference ECG-Mapping Etalons Improve the
Diagnostic Accuracy of Myocardial Ischemia
According to Departure Isointegral Surface Maps

Slavomira Filipova^a, Milan Tysler^b, Michaela Turzova^b, and Vladimir Rosik^b

^aDepartment of Cardiology Institute of Cardiovascular Diseases and Slovak Health University, Bratislava, Slovakia
^bInstitute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

Correrspondence: S Filipova, Department of Cardiology, Slovak Health University and Slovak Institute of Cardiovascular Diseases,
Pod Krasnou horkou 1, SK 833 48 Bratislava, Slovakia.
E-mail: filipova@susch.sk, phone +421 2 59320282, fax +421 2 55424049

1.  Introduction

Previous clinical studies with departure isointegral body surface potential maps (D-IBSPM) have shown that strictly normal composition of the reference sample (with ideal ST-T wave morphology) may lead to an unwanted amount of false positive findings, especially in the course of examination of patients with various degrees of coronary heart disease (CHD), arterial hypertension (AHT) with or without left ventricular hypertrophy (LVH) [Filipova et al., 1995; Filipova et al., 1999; Bacharova et al., 2002]. Then the patients with acute myocardial infarction (AMI) or recent myocardial ischemic damage (OMI) are correlated through the “ideal” reference sample in the course of D-IBSPM exami-nation or other procedure [Szathmary and Ruttkay-Nedecky, 1981].

The aim of the study was to compare the effect of using reference samples with well defined pathologies in order to remove the confounding influence of chronic clinical status without focal defects of ventricular activity (chronic CHD, AHT) on the signs of acute and old local myocardial ischemic ECG changes.

2.  Material and Methods

The special programme of the integral departure mapping in the mapping advice CARDIO PC (In-stitute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia) was used to cumulate data from volunteers and patients with well-defined pathologies and to create reference samples with the specified clinical characteristics [Tysler et al., 1999].

The reference samples (averaged IBSPM maps) were created from well-documented individual volunteers and patients (n= 345): (1) healthy subjects without any organic or functional cardiovascular disorders - NORM (n = 76); (2) hypertensive patients without any forms of CHD – HT ( n = 92);

(3) normotensive patients with clinical signs of CHD, but without MI–NOIC (n =107); (4) patients with AHT together with chronic or stabile types of CHD, without MI - HTIC (n = 79).

All reference samples (etalons) represent the averaged isointegral maps with respect of standard de-viation parameters in numeric and graphic (mapping) forms for various integrated period of P-QRS-T.

3.  Results

(1) The above reference samples NORM and NOIC were used for construction of D-IBSPMs for in-

      dividual patients with well-documented: individual hypertensive patients with/without LVH; indi-

      vidual patients with AMI/OMI without AHT/LVH; individual patients with AMI/OMI with LVH.

(2) The reference samples HT and HTIC were used as the background for the construction of

      D-IBSPMs for well-documented: individual patients with hypertensive patients with / without 

      LVH; individual patients with hypertensive patients with CHD with / without LVH.

(3) According to our results, the highest incidence of false positive signs of myocardial injury (false

      MI, false residual ischemia) was observed if hypertensive patients with LVH, when they were

      compared with either  the reference sample NORM or NOIC.

(4) LVH created the significant negative regional abnormalities in  D-IBSPMs of ST-T period  specifi-

      cally located on the superior part of anterior and posterior thoracic wall ( Figure 1).

4.  Discussion and Conclusions

We have proposed to use the different reference samples for D-IBSPMs, adequate to the basic  cli-nical characteristics of the patient examinated. Presence of LVH and well-documented chronic form of CHD influenced significantly QRS, and especially ST-T period of ventricular activation. It is possible to enlarge and to adjust all types of etalons for D-IBSPM according to the patients’ clinical and ECG information and on the basis of criteria for etalons.

References

Bacharova L, Kyselovic J, Klimas J. QRS voltage-duration product in the identification of left ventricular hypertrophy in spontaneously hypertensive rats. Arq. Bras. Cardiol., 79 (2):143-148, 2002.

Filipova S, Cagan S, Dubrava J, Tysler M, Kneppo P, Rosik V. Diagnostic applications of body surface mapping in the clinical cardiology : The role of the norm definition for the correct using of the integral departure mapping. In: Advances In Body Surface Mapping and High resolution Electrocardiography. ( Yasui S, Abildskov JA, Yamada K, Harumi K, Eds.). Life Medi-com Co, Nagoya, 1995, 109-122.

Filipova S, De Ambroggi L, Mikus P, Tysler M, Rosik V, Turzova M, Kneppo P, Riecansky, I. The different characteristics of body surface cardioelectric field for hypertensive heart with LV hypertrophy: ECG–mapping study. J.Hypertension, 17(Suppl.3):S233, 1999.

Szathmary V, Ruttkay-Nedecky I. Etalon (standard) for surface potential distribution produced by electrical activity of the heart. Physiol.Bohemoslov. 30(3):231, 1981.

Tysler M, Rosik V, Turzova M. Practical system for BSP mapping studies. In: Electrocardiology ’98 (Preda I, Ed.). World Scientific, Singapore-New Yersey-London-Hong Kong, 1999, 81-84.