Diagnosis of acute myocardial infarction in patients with chronic left bundle-branch block - Standard 12-lead ECG compared to dynamic vectorcardiography

Standard 12-lead electrocardiogram (ECG) criteria were evaluated and compar ed with dynamic vectorcardiography for diagnosing acute myocardial infarcti on in 33 patients with chronic left bundle-branch block. In 14 patients a c linical diagnosis of acute myocardial infarction was made, but it was found that none of the seven most promising ECG criteria suggested in the litera ture could alone or in combination diagnose acute myocardial infarction. QR S vector difference evolution showed the same kind of pattern as that for p atients with narrow QRS-complex. By using a predefined specific pattern, a diagnostic accuracy of 79% was achieved. The results indicate that dynamic vectorcardiography is a better tool for diagnosing and monitoring acute myo cardial infarction in patients with left bundle-branch block than standard 12-lead ECGs taken on admission and after 12-24 h.