Solving inaccuracies in the heart position and orientation for inverse solution by using electric information

Abstract

Electrocardiographic Imaging (ECGI) has become an increasingly used technique for non-invasive diagnosis of cardiac arrhythmias, although the need for medical imaging technology to determine the anatomy hinders its introduction in the clinical practice. This work explores the ability of the L-curve curvature for identifying the location and orientation of the atrial surface inside the torso. Surface electrical signals from 31 mathematical models and four AF patients were used to estimate the optimal position of the atria inside the torso. The curvature of the L-curve from the Tikhonov method was measured after application of deviations in atrial position and orientation. Independent deviations in the atrial position were solved by finding the maximal L-curve curvature with an error of 1.7±2.4 mm in mathematical models and 9.1±11.5 mm in patients. Independent angular deviations were solved with an error of 5.8±7.1° in mathematical models and 12.4°±13.2° in patients. Under superimposed uncertainties in the 3 axis of translation and in the 3 axis of rotation, the error in location was of 2.3±3.2 mm and 6.4°±7.1° in mathematical models, and 7.9±10.7 mm and 10.0°±12.8° in patients. The curvature of L-curve is a useful marker for emending the inaccuracies the cardiac location and would allow to combine torso and heart anatomies extracted from different image techniques.