Localization of prior myocardial infarction by repolarization variables

Background: To find quantitative, automatically applicable electrocardiographic (ECG) variables for detecting prior myocardial infarction (MI) in different myocardial regions. Methods: Observational study. Body surface potential mapping (BSPM) was recorded at rest, and automatically analyzed with regard to ECG parameters, blinded to the clinical characteristics of the study subjects, 144 patients with prior MI and 75 healthy controls. MI location was determined by cine angiography or echocardiography as anterior (66 patients), inferoposterior (89 patients), and lateral (15 patients). Patients' 12-lead ECG was interpreted according to Minnesota code (Q-wave MI in 97 patients). The QRSSTT, QRS, and STT integrals, and the T-apex amplitude in detecting prior anterior and inferoposterior MI were analyzed. Results: The T-apex amplitude, QRSSTT integral, and STT integral were functional in detecting NIT in all tested locations on a single-lead basis, with areas under receiver operating characteristic curves (AUC) of over 90% (p < 0.001) in optimal sites. In the best leads AUC for the QRSSTT integral in anterior MI was 93% (CI 87-99%) and for the inferoposterior MI 92% (CI 88-97%). These repolarization variables outperformed the Minnesota code in all tested MI locations. They were also able to distinguish between anterior and inferoposterior MI with an AUC of > 85% (p < 0.001). Conclusions: Quantitative, automatically applicable single-lead repolarization variables detect prior MI irrespective of its location. They may simplify the screening for and localization of old infarctions as compared to the conventional ECG methods. (C) 2007 Elsevier Ireland Ltd. All rights reserved.