Load dependent changes of cardiac depolarization and repolarization during exercise ECG test

The trend of the morphology changes of cardiac depolarization and repolarization during exercise ECG test were examined in a group of J 06 individuals. The ratio between the second and the first eigenvalues of Principal Component Analysis (PCA) was considered. The increasing and decreasing trends of PCA _QRS and PCA_T were classified as homogeneous and the rest as heterogeneous and their relationship with clinical data were studied. Depolarization: an increasing percentage of heterogeneous trends were observed in the groups with cardiac risk factors. This trend was statistically significant in the dyslipidemia disease (p<;0.05). Repolarization: opposite to the depolarization, an increasing percentage of the homogeneous trends was obtained in the groups with cardiac risk factors, with statistically significant diferences considering coronary artery disease and percutaneous coronary intervention (p<;0.05). The study of the load dependent behavior of PCA index during the stress test has revealed an increasing percentage of homogeneous and heterogeneous trends respectively in T and QRS wave, which can help to a better characterization of the diagnostic value of the exercise test.