Reference for Electrocardiographic Imaging-Based T-Wave Alternans Estimation

Figures

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  FIGURE 1.. Comparative analysis of T-wave segmentation methods. (a) Differences between epicardial (odd rows) and torso (even rows), with even and odd T-waves segmented using the AS (left) and SRS (right) methods for a control subject (top two rows) and an ICM patient (bottom two rows). (b) Histograms depicting the distribution of differences between even and odd T-waves from epicardial (top row) and torso (bottom row) signals, for the controls group (left) and patients group (right), obtained using the bootstrapping technique.

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  FIGURE 2.. Even and odd T-wave templates at a mesh point in a synthetic patient along with the modifying gaussian-shaped curve (left), and an enlarged view of the added gaussian modulation (right).

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  FIGURE 3.. Analyses of false positive and false negative rates for increasing baseline and white noise amplitudes in synthetic patients. (a-b) False positive rates with increasing amplitudes of baseline (a) and white (b) noise for synthetic patients 1 (top), 2 (middle), and 3 (bottom). (c-d) False negative rates with rising baseline (c) and white (d) noise amplitudes for synthetic patients 1 (top), 2 (middle), and 3 (bottom). (e-f) ECG signals at an epicardium mesh point affected by baseline (e) and white (f) noise (top), showcasing the filtering process (middle) and the residuals generated by subtracting the original signal from the filtered one (bottom).

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  FIGURE 4.. TWA maps and corresponding TWA signals at various points surrounding a target point, estimated by the TM, SM, and MMA in the epicardium and torso of a synthetic patient. Rows depict scenarios with no noise (top), baseline noise (middle), and white noise (bottom), while columns correspond to TM (first and fourth), SM (second and fifth), and MMA (third and sixth) TWA estimations. Mesh colors represent the maximum absolute value of the estimated TWA signal.

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  FIGURE 5.. Impact of synthetic alternans amplitude on TWA estimations in real control subjects. False positive (a) and negative (b) rates with varying amplitudes of synthetic alternans added, illustrating TWA estimation by TM (top), SM (middle), and MMA (bottom).

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  FIGURE 6.. TWA maps (left) and histograms of the distribution of TWA in a control subject epicardium (top) and torso (bottom), with TWA estimated by the TM (second column), SM (third column), and MMA (right). Red circles denote CI right limits, while green circles represent empirical values for each mesh point, and mesh color indicates conformity of empirical values with their respective CIs.

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  FIGURE 7.. Affected epicardium (top) and torso (bottom) surfaces as the amplitude of synthetic alternans increases in control subject 1 (a) and 2 (b).

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  FIGURE 8.. Epicardium (top) and torso (bottom) TWA maps (odd columns) and histograms of the distribution of TWA (even columns) in a real control subject with 125μV synthetic alternans amplitude added, with TWA estimated by TM (left), SM (middle), and MMA (right). Red circles denote CI right limits, green circles represent empirical values, and mesh color indicates whether empirical values are inside (blue) or outside (yellow) the CIs.

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  FIGURE 9.. TWA maps (left) and histograms of the distribution of TWA in an ICM patient epicardium (top) and torso (bottom), with TWA estimated by the TM (second column), SM (third column), and MMA (right). Red circles denote CI right limits, while green circles represent empirical values for each mesh point, and mesh color indicates conformity of empirical values with their respective CIs.

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  FIGURE 10.. Epicardium (top) and torso (bottom) TWA maps (odd columns) and histograms of the distribution of TWA (even columns) in a LQTS patient, with TWA estimated by TM (left), SM (middle), and MMA (right). Red circles denote CI right limits, green circles represent empirical values, and mesh color indicates whether empirical values are inside (blue) or outside (yellow) the CIs, with a blue-green color if all the empirical values are inside their corresponding CI.