Changes in the ST- and ventricular gradient vectors over a period of 25 years

The ECG is a major diagnostic instrument for the detection of acute ischemia and subsequent triaging of patients after first medical contact in the setting of acute coronary syndrome. However, sensitivity and specificity of the ECG with current diagnostic criteria are limited. When a previous non-ischemic ECG is available for reference purposes, comparison of the acute and reference ECG by serial analysis is known to increase sensitivity. For acceptable specificity in serial comparison it is a prerequisite that a reference ECG remains valid (is stable) in time.