New Vectorcardiographic non-planarity measure of T-wave loop improves separation between healthy subjects and myocardial infarction patients

Principal component analysis of vectorcardiographic T-wave loop has been shown to be a potential tool to describe the abnormality of the cardiac repolarization and to predict cardiac events in patients with cardiac disease. In this paper a new method for estimating the non-planarity of the T-wave loop is introduced and tested with healthy subjects and subjects with anterior or inferior myocardial infarction. The method is based on the resamping of T-wave data points with respect to the arc-length, the total least squares plane fitting, the identifying and reordering of the fitted axes, and decomposing the optimal rotation matrix. A recently published related measure, PCA3, was used for comparison purposes. The results showed that the non-planarity of T-wave loop increased significantly in patients with myocardial infarction compared to the healthy group. The new method separated healthy and patient groups with p-value 0.002 while PCA3 only with p-value 0.075. The new method was superior to PCA3 in separating the healthy patients from both infarction types.