Impact of the torso model on the inverse localization of ischemia

Summary

In this simulation study the accuracy of the inverse localization of an ischemic lesion was investigated if a patient-adjusted general torso model and four different approximate heart models were used. Surface ECGs were simulated by a normal heart and by hearts with 18 different ischemic lesions in 7 realistic torso models. Position of each lesion represented by a single dipole was then searched by an inverse solution. Difference QRST integral maps reflecting differences between cardioelectric fields of the ischemic and normal hearts were used. With a standard heart model the mean error of the lesion localization was 3.4 cm. With a standard heart model shifted to an inversely estimated position this error was 3.9 cm, for an equally shifted and properly formed and rotated heart model the error was 2.4 cm and for a heart model properly shifted, formed and rotated the error was 1.1 cm. If realistic CT or MRI-based torso model was used the lesion localization error was 0.7 cm. From the results it can be concluded that use of adjusted standard torso model with properly positioned and formed standard heart model can lead to acceptable accuracy of the inverse localization of an ischemic lesion.

Keywords:
Ischemic lesion, Body surface potential mapping, Inverse solution, Torso and heart model