Abstract. The demand for diagnostic ECG is increasing for several reasons, even outside the realm of cardiology. In large-scale epidemiological studies the detection of previous myocardial infarction, even when silent, is difficult task at any age. Digital ECG could increase reproducibility and improve differentiation between repolarization abnormalities due to the reliquates of ischemic episodes. We sought a simpler ECG measurement to represent disturbances of ventricular repolarization: QT dispersion (QTd), T axis and the Selvester Scoring System. All these parameters are just examined by many authors as indices of previous acute myocardial infarction (AMI).The aim of this paper is to investigate which one is the best AMI indicator: we tested their efficacy to reveal nonQ-AMI and Q-AMI in a population of patients with validated diagnosis of AMI (enzyme modification or echocardiographic abnormality) occurred from tree months to three years before our electrocardiographic evaluation, versus healthy subjects (controls: cases ratio=11:2). We considered 562 subjects: 87 cases of whom 38 Q-AMI and 49 nonQ-AMI, excluded patients with ventricular hypertrophy, stable and unstable angina, major arrhythmias, bundle blocks, pacemakers or enzyme modification in the moment of valuation; the controls are 475 subjects in good health without early cardiovascular familiarity or cardiac disease documented. Aged 20-65 years, males and females (sex ratio 9:1) underwent ECG digital registration. The ECGs were recorded in SCP formats with ET Excel 106. QTd was computed as the difference between the maximum and the minimum QT interval in 12-lead ECG. We divided the QTd into three categories (1°:<45 ms, 2°: 45-70 ms, 3°: >70 ms) and we considered the last one (>70 ms). T axis was computed from vectorcardiographic X, Y, and Z leads, and was categorised in three groups: Normal (15° to 75°), Borderline (-15° to 15° and 75° to 105°) and Abnormal (-15° to -180° and 105° to 180°). The Selvester Scoring System was computed by the original digital program SYLVESTER and we considered two categories: Normal (≤ 3 points) and Abnormal (> 3 points). Our results were: QTd had less sensitivity (0,35) and less specificity (0,34), Taxis had high specificity (0,83) and high predictive value of negative test (0,85) and Selvester Scoring System had high totally sensitivity (0,74) with high sensitivity for Q-AMI (0,89) and for nonQ-AMI (0,79). From these data we concluded that the Selvester Scoring System is the best marker for identifying previously AMI in a population with suspect of AMI, instead T axis is a more precise index for excluding previous AMI and it can be used on a large scale as a screening test in healthy populations.