Session S35.2

Estimation of Area at Risk in Myocardial Infarction

J Carnicky*, J Ubachs, A Mateasik, GS Wagner, L Bacharova

International Laser Centre
Bratislava, Slovakia

ST deviation in acute myocardial infarction (MI) has been shown to estimate the amount of myocardium in jeopardy, therefore quantitative methods allowing the estimation of the location and extent of area at risk could contribute to the clinical decision regarding acute reperfusion therapy. The DECARTO method [1] using X, Y, Z electrocardiograms as input data provides a method to transform orthogonal ECGs into “areas of activation” with the time varying size and location on a spherical surface approximating the ventricular wall. The method depends on the orientation and magnitude of the resultant spatial vector. DECARTO was originally elaborated for the QRS complex, however, in this study it was adapted for topographic presentation of the ST vector. A semi-orthogonal subset of the standard 12-lead ECG (V2, V5, aVF) was used as the input data. The ST segment voltage values were transformed using the DECARTO model and the estimated spatial ST vector was projected on a virtual sphere surface. This spherical image surface was subsequently transformed to fit the approximate anatomical position of the heart in the chest. DECARTO-like ST projections of 10 patients with AMI were constructed and compared to the Selvester 12-lead ECG estimate of the location and extend of the risk area, and to SPECT images. The accordance among the 3 methods with respect to the risk area location was achieved in individuals in whom the maximum ST deviations were in the three selected semi-orthogonal leads (8 of 10 patients). In two patients with the maximum ST changes in V3 and V4, and only minor changes in any of the selected leads, respectively, the location of the estimated risk area using DECARTO-like presentation was discordant with respect to both the 12-lead ECG risk area estimates and SPECT images.These results suggest that the DECARTO-like presentation of the ST vector can identify the location of the risk area, only when the spatial ST vector is maximal in the included leads. Otherwise, the location of the risk region must be calculated using an extended subset of the 12-lead ECG. 1.Titomir LI, Ruttkay-Nedecky I: Chronotopography: a new method for presentation of orthogonal electrocardiograms and vectorcardiograms. Int J BioMed Comput 20, 1987, 275.

(Abstract Control Number: 20)