Derivation of 12-lead/18-lead electrocardiogram and vectocardiogram from subsets of 12-Lead electrocardiogram with only 2 chest leads

Abstract

The objective of this study was to develop and evaluate transformation coefficients for synthesis of standard 12-lead electrocardiogram (ECG), 18-lead ECG (with additional leads V7, V8, V9, V3R, V4R, and V5R), and Frank vectocardiogram (VCG) from reduced lead sets using 3 limb electrodes at Mason-Likar sites combined with 2 chest electrodes chosen from V1 to V6 sites. There are 15 such lead-set combinations, and each can be recorded with 6-wire cable. We used a study population from a Dalhousie University (Halifax, Nova Scotia, Canada) database, consisting of 892 individuals: 290 healthy subjects, 497 patients who previously suffered a myocardial infarction, and 105 patients with a history of spontaneous ventricular tachycardia but no evidence of a previous myocardial infarction. For each subject, 120-lead ECG recordings of 15-second duration were aligned and averaged, all samples of the QRST complex for leads of interest were extracted, and these data were used to derive—by regression analysis— coefficients for lead transformations. The coefficients were then used to reconstitute complete 12-lead/18-lead ECG and VCG from 15 predictor sets, and the success of this synthesis was assessed by 2 measures for goodness of fit: similarity coefficient (SC in percentage) and relative error (RE in percentage). Our results show that chest leads V2 and V4 are the best pair for reconstituting the 12-lead ECG (SC = 96.91, RE = 25.53), followed closely by V3 and V5, V2 and V5, V3 and V4, and V1 and V4. The best pair for reconstituting the entire 18-lead set is V1 and V4 (SC = 93.82, RE = 31.93), followed byV1 and V3, V1 and V5, and V1 and V6. The best pair for synthesis of the Frank X, Y, Z leads is V3 and V6 (SC = 96.31, RE = 26.07), followed by V1 and V3, V1 and V4, and V3 and V5. In conclusion, our study demonstrates that good approximation of 12-lead/18-lead ECG andVCG can be achieved by using a lead system using 6-wire cable, provided that electrodes are judiciously placed.