Derived electrocardiograms on the posterior leads from 12-lead system: method and evaluation

Correct interpretation of electrocardiogram (ECG) is important for treatment of patients with acute myocardial infarction (AMI). A large number of posterior AMI manifests ST elevation in posterior leads V7-V9 that are beyond the standard 12-lead ECG. In this paper, we propose a method where ECGs on posterior leads V7- V9 are derived from the standard 12-lead ECG. The posterior ECGs are calculated by a linear combination of eight measured ECG signals based on information redundancy in the 12-lead ECG system. One part of a 15-lead ECG database is used to derive a transfer matrix based on the least squares method, which represents the inherent relation among body surface ECG potentials. The other part of the database is used to evaluation the derived posterior ECG by comparing the derived ECGs with measured ones. A quantitative evaluation is performed with an automatic ECG interpretation program. The results show the accuracy of derived posterior ECGs is sufficiently good to provide useful information in diagnosis of posterior AMI.