ABC | Volume 113, Nº1, July 2019

Review Article Pastore et al ECG/VCG in the current clinical practice Arq Bras Cardiol. 2019; 113(1):87-99 Figure 1 – Electrocardiogram vs. Vectorcardiogram. The classic aspects of the ECG/VCG association in the differential diagnosis of myocardial infarctions, conduction disorders, atrial and ventricular hypertrophies, and the correlations between these electrical disorders are still valid and assertive. 12,13 The association of these pathologies is further clarified when they are seen through the ECG/VCG dyad. (Figure 1) Based on the abovementioned facts, during the last decade we were able to develop the performance of the binomial electrovectorcardiogram in the context of the most varied pathologies. This binomial can add sophistication to the already known clinical entities, in addition to a greater accuracy of the recent electrocardiographic definitions (such as Brugada, early repolarization, etc.) Our experience, both academic and scientific, led us to join these new ECG/VCG acquisitions, and to open a window into the observation of the electrical phenomena of the heart. The literature has shown that the more sophisticated vectorcardiogram makes it easier for us to observe punctual phenomena that are not defined by the ECG. Limitations Because there are only a few centers that are capable of performing routine vectorcardiography, there remains no doubt that this comparative study requires specific training, just like any other diagnostic method, through didactic bibliography and distance learning material. The purpose of this publication is guided by the acknowledgement of this situation. The electrovectorcardiography binomial The experience with the VCG during these last decades shows the greater specificity and sensitivity of this method to detect the subtleties of these diagnoses. In comparison with the ECG, the VCG shows some advantages; however, when in association, they can help us differentiate between some very ordinary situations in clinical practice. The three-dimensional spatial orientation of both the atrial and the ventricular activity provides a far more complete observation tool than the linear form of the ECG. The modern analysis of the ECG and its respective VCG, simultaneously obtained by the recent technique called electro‑vectorcardiogram (ECG/VCG), brought a significant gain for the differential diagnosis of some pathologies. 1,3,4,8,14,15 (Figure 2) The electro-vectorcardiographic analysis is very rich and consistent for the diagnosis of myocardial infarctions (MI), since the difficulties in defining pathological Q waves or the loss of R waves in the ECG can be very clearly visualized in the ECG/VCG. This association helps us to define the real changes in the direction and orientation of the vectorcardiographic loops created by the areas of myocardial infarction, in both the transverse and the frontal planes. 16-18 (Figure 3) Another important differential aspect obtained by the electro-vectorcardiogram is the investigation of the presence of a myocardial infarction area in the inferior wall, of a left superior fascicular block, or the association of both pathologies. The association of MIs with the presence of fascicular or troncular blocks can be fully characterized by the ECG/VCG association. The inferior MIs with a left anterosuperior fascicular block (LASFB), and the anterior MIs with a right bundle-branch block (RBBB) are typical examples of the importance of the ECG/VCG association for a differential diagnosis. 19,20 (Figures 3A and 4A and B) The spatial orientation of the fascicular blocks can be better understood through the electro-vectorcardiogram. The septal vector orientation and the direction of the vectorcardiographic loop activation neatly characterize the fascicular blocks and their associations through the ECG/VCG, since they define the electrical path of this phenomenon, thus characterizing exactly the position of the blocks. 21-24 (Figures 4A and 5(A and B) 88