Vector u loop in patients with old myocardial infarction

Abstract

Summary:The U loop of the vectorcardiogram was examined qualitatively and quantitatively in 100 normal subjects and 67 patients with old myocardial infarction, using a direct-writing vectorcardiograph with memory function. In the control group, the U loop was directed to the left, anteriorly and inferiorly, and it was inscribed counterclockwise in the horizontal plane. In patients with anterior myocardial infarction, the U loop tended to be displaced to the right, and in patients with inferior myocardial infarction to the right and superiorly. The shape of the U loop in patients was also different from that of normal subjects. The maximum U vector was significantly smaller in magnitude both in patients with anterior and inferior myocardial infarction than that of normal subjects (p<O.Ol). In patients with ventricular aneurysm, the magnitude of the maximum U vector was significantly smaller and its direction was displaced more to the right and posteriorly than those without aneurysm (p<O.Ol). In standard 12-lead electrocardiogram (ECG), observation of the U wave in patients with old myocardial infarction was difficult, especially in the limb lead, because of the small size of the U wave. Therefore, vectorcardiographic observation may be more useful than electrocardiographic observation for the analysis of the U wave in patients with old myocardial infarction.

A review of beat-to-beat vectorcardiographic (VCG) parameters for analyzing repolarization variability in ECG signals

“…Now, the VCG signal can be directly recorded via the Frank lead system or can be derived from the ECG signal using a transform method [singular value decomposition (SVD) or inverse Dower transform (IDT)] or via matrix coefficients (Kors). In addition, VCG loops may have clinical importance for detecting cardiac diseases such as myocardial infarction or myocardial injury in coronary surgery over conventional ECG analysis [19,94], which is not easy to observe from a scalar ECG signal. Therefore, it has been proposed over recent decades by various researchers that VCG has significant utility compared to the standard 12-lead standard ECG [13,14,60,84].…”