The aim of the study was to determine: – whether in patients with acute myocardial infarction (AMI) the duration of the QTc interval correlates with the echocardiographically determined left ventricular wall motion abnormality score (WMSI), – whether patients with AMI show a correlation between the duration of the QTc interval and frequency and complexity of ventricular ectopic activity, – whether there is a correlation between the WMSI and the incidence and complexity of ventricular arrhythmias. In a series of 40 consecutive patients with a 4-day history of AMI, left ventricular WMSI and QTc intervals in ECG leads corresponding to the site of AMI, were determined. 24-hour ECGs were recorded and graded according to Lown. A statistically significant positive correlation was found between the WMSI and the QTc interval duration (r = 0,75; p < 0,001), especially in patients with anterior AMI (r = 0,94; p < 0,001). The WMSI was higher in patients with high-degree (Lown 3-5) ventricular ectopic activity (p < 0,05). There was no significant correlation between the duration of the QTc interval and the complexity of ventricular ectopic activity.