Electrocardiographic and scintigraphic imaging of myocardial ischemia

The aim was to further validate the electrocardiographic imaging method we introduced previously - involving inverse calculation of heart-surface potential distributions from the 12-lead ECG - by comparison with data provided by single photon emission computed tomography (SPECT). To perform the electrocardiographic inverse solution, we used a torso model with 352 body-surface and 202 heart-surface nodes. Coefficients for estimating 352 body-surface potentials from 12-lead ECG were developed from the design set (n = 892) of body-surface potential mapping (BSPM) data. The test set consisted of 12-lead ECGs of 31 patients from the STAFF III dataset (Duke University Medical Center; Lund University) who underwent elective percutaneous coronary intervention (PCI) of the LAD (n = 8), LCx (n = 5), or the RCA (n = 18) and had SPECT performed. BSPM distributions at J point were estimated from the 12-lead ECG and used to calculate bull's-eye displays of heart-surface potentials. The latter displays were found to have the area of positive potentials corresponding in all but 2 cases with the underperfused territory indicated by SPECT. For the LAD and LCx groups all ECG-derived bull's-eye images featured positive potentials in the expected territory and were consistent with SPECT images; for the RCA group 13/18 ECG-derived bull's-eye images indicated the expected territory, but 3/5 of "misclassified" cases were consistent with SPECT images. Therefore, our findings suggest that electro-cardiographic imaging based on just the 12-lead ECG might yield estimates of myocardial ischemic regions that are consistent with those provided by SPECT.