Abstract. To evaluate changes of the electrical potential loss, we looked for quantitative body surface potential mapping (BSPM) parameters which are characteristic of either Q or non-Q wave myocardial infarction (MI).

Methods. BSPM using 63 unipolar leads was recorded in 86 patients with Q-wave MI (localization: 36 anterior or anterior + lateral/septal/inferior, 30 inferior/septal/high lateral, 20 posterobasal or posterobasal+inferior), 71 patients with non-Q-wave MI (26 anterior, 45 inferior) and in 24 healthy adults. MIs were localized using standard ECG recording in the acute and chronic phase. Coronary-angiography, ventriculography and thallium scintigraphy supported the diagnosis.

Results. During the depolarization, the ratio of the peak maximum and peak minimum potentials (Max/Min) of the normal group (0.974 ± 0.298) significantly differed from the Max/Min value of the anterior Q-MI (0.41 ± 0.091, p<0.0001), posterobasal Q-MI (2.25 ± 1.46, p<0.002) as well as anterior non-Q-MI (0.84 ± 0.31, p<0.05) and inferior non-Q-MI (1.72 ± 0.59, p<0.001). The inferior/septal/high lateral MI (1.02 ± 0.181) did not show difference from the normal value. The reason of the differing values is the eccentric position of the heart: the electromotive forces of the anterior epicardium influence the total BSPM values to a greater degree than electromotive forces of the posterior epicardium. During the effect of acute nitroglycerine, repeated BSPM resulted in favorable changes in various degree in the Max/Min value (1-24 %) depending on the size and location of the viable myocardium. The use of retard nitrates decreases these favorable changes.

Conclusions. Our new numerical parameter, the Max/Min, depends on the location, extension and viability of the electrically damaged myocardium. It may be suitable for monitoring the effect of various drugs (e.g. nitrates) or detecting the result of the coronary artery intervention.