OBJECTIVE: To assess the possibilities of ECG in prediction of an infarcted artery in patients with acute myocardial infarction (AIM) and evaluate the relationship of left ventricular function to the number of pathological Qs.

METHOD: The trial comprises 216 patients with acute myocardial infarction (AMI) treated by primary PTCA. The diagnosis of AIM was confirmed in addition to ECG also by coronarography and elevation of cardiospecific enzymes. On the baseline 12-lead ECG denivelization of the ST segment > 1 mm was considered significant. The number of pathological Q waves on the ECG tracing on discharge was compared with left ventricular function according to the ejection fraction assessed echocardiographically before discharge.

RESULTS: Elevation of ST in leads V1-V4 predicts occlusion of LAD with a sensitivity of 96% and specificity of 69% (p < 0.001 vs. RC segment with a sensitivity of 80% and specificity of 48% (p < 0.001). In inferior AMI the ST elevation in III > II develops in 70% in occlusion of RCA vs. 27% in occlusion of LCX. The mean left ventricular ejection fraction before discharge was in patients with four or fewer pathological Q waves 49 +/- 10% vs. 32 +/- 9% in the presence of pathological Q waves in > 4 leads.

CONCLUSION: In patients with AMI according to ECG changes in different leads conclusions may be drawn on the infarcted artery. The presence of pathological Q waves in more than 4 leads predicts severe left ventricular dysfunction.