Reproducibility of ST and ventricular gradient vectors

In this study, we tested the reproducibility of the ST vectors at the J point and 60 ms after the J point, and the reproducibility of the ventricular gradient. The reproducibility of these ECG variables was compared with the proposed thresholds for ischemia detection by serial ECG analysis (comparison of an acute ECG suspected of the presence of acute ischemia with a previously made non-ischemic ECG in the same patient). In a group of 398 patients with various cardiovascular pathology we measured the diferences in the ST vectors and in the ventricular gradient in ECG pairs about one year apart. All ECGs were non-ischemic, and electively made in the outpatient clinic. ST and VG vector diferences exceeded only in around 20% of the cases the proposed sensitive thresholds for ischemia. The results of our study suggest that the reproducibility of the ST and VG vectors in non-ischemic ECGs is good, thus indicating that the expected amount of false positive detections of ischemia by serial ECG analysis is likely to be low.