QRS Patterns in Anterior Subendocardial Infarction : By Means of Simulation of Propagation Process and Computational QRS Reconstruction

Abstract

The purpose of this paper is to reconstruct electro- cardiographic QRS complex of various kinds of size of anterior transmural, nontransmural, and subendocardial infarctions with the methods of computer simulation of the propagation process in excitation of the ventricles and of computed QRS complex reconstruction in which the concept of transfer impedance is utilized, in order to discuss (1) the changes of propagation process in excitation of ventricles by infarction, (2) whether abnormal Q wave is found in subendocardial infarction, (3) the genesis of abnormal Q wave and (4) the difference of QRS complex between anterior transmural and subendocardial infarction. Method By means of "computer simulation of the propagation process in excitation of the ventricles" and "computed reconstruction of electrocardiographic QRS pattern", the propagation process in excitation of the ventricles and electrocardiographic QRS patterns in infarction were obtained. It is assumed that the excitation was not propagated to all conductive system and cardiac proper muscles which suffered from infarction, and that heart electromotive force was not generated by excitation wave front. In this paper, left ventricular anterior wall was divided into subendocardial, intermediate and subepicardial layer for convenience' sake. Infarction located in subendocardial and intermediate layer was called nontransmural and infarction located in subendocardial layer was called subendocardial infarction. Three cases of Group A have in common to the location and spread of infarction on endocardial surface. Five of Groups B and C were simulated centering around left ventricular wall. Result and Discussion In A-1 (large anterior transmural infarction), large S wave in V^{2, 3} and QS pattern in V₄ were found. In A-2 (large anterior nontransmural infarction) and A-3 (large anterior subendocardial infarction), late R in V^{2, 3, 4} and QR pattern in V₄ were found. Duration of QRS complex widened. Extent of infarction on endocardial surface was common to the two cases of Group B. Volume of infarction in B-1 was four times as much as that in B-2. In B-1 (moderate-sized anterior transmural infarction), S waves in V^{2, 3} were larger than those without infarction and abnormal Q wave was found in V₄. In B-2 (moderate-sized anterior endocardial infarction), late R was found in V^{2, 3} and Q wave in V₄.