Electrocardiographic Imaging in Atrial Fibrillation: Selection of the Optimal Tikhonov-Regularization Parameter

Abstract

[EN] Electrocardiographic imaging (ECGI) allows evaluating the complexity of atrial fibrillation (AF) signals using the Boundary Element Method and Tikhonov regularization. An accurate ECGI reconstruction is dependent on a proper selection of the regularization parameter (¿). In this work, two ranges of ¿ are explored to evaluate the effect of ¿ on the quality of the ECGI reconstruction. ECGIs of 20 AF patients were computed using zero (T0), first (T1) and second (T2) order Tikhonov regularization (TR) for two ranges of ¿: from 10-9 to 102 and 10-12 to 10-4. Dominant frequencies (DF) and the number of rotors obtained with the two ranges and methods were compared. Zero-order Tikhonov showed to be more robust in ¿ selection for different ¿ ranges. For lower ¿ ranges, higher DF was found (T2, p<0.05) and more rotors were detected for T1 and T2 (p<0.01). Differences between TR methods compared by ¿ ranges showed more variability in derived metrics for lower ¿ range (p<0.01). Optimal ranges for ¿ search differ among T0, T1 and T2. Election of lower than optimal ¿ values result in an increased estimated electrical complexity.