Evaluation and Classification of Atrial Arrhythmias from Signatures in Electrographic Flow Metrics

Figures

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  Figure 1:. Electrographic flow (EGF) and electrogram (EGM) rhythm differences. A: Example EGF maps in three atrial arrhythmias. In the atrial fibrillation (AF) recording, there are chaotic wavefront collisions and more areas of low EGF consistency (EGFC) (blue) versus high EGFC (purple). An active source at D3 emits flow near the broadest patch of high EGFC. In the atrial flutter (AFL) recording, there are more organized high EGFC areas versus low EGFC areas. The active source at B7–C7 emits flow in all directions, and there is re-entry around the C3–D3 passive rotor. In the atrial tachycardia (AT) recording, flow diverges from a focal source with broadly high EGFC creating organized but non–re-entrant circuits. B: Respective EGMs of the EGF maps in A. In the AF EGM, fibrillatory waves are apparent, and the R–R interval length is variable, yielding a low mean R–RC score and a high disorganization score. In the AFL EGM, there are organized P-waves and some related but non-consecutive R–R intervals, such as at 1.3–1.9 s and 2.6–3.2 s, yielding a low mean R–RC score but a low disorganization score. In the AT EGM, there are organized P-waves and R–R intervals of a consistent 0.4-s length,…

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  Figure 2:. Electrographic flow (EGF) metric distribution by rhythm. Scatter and shape of the distribution are shown. Map metrics are shown in the left column with lower EGF consistency (EGFC) and activity in atrial fibrillation (AF) versus atrial flutter (AFL) and atrial tachycardia (AT) but higher flow angle variability (FAV). Electrogram (EGM) metrics are shown in the right column with a lower mean atrial cycle length (CL) in AF and AT versus AFL, lower mean R–R correlation (R–RC) score in AF versus AFL and AT, and higher disorganization score in AF versus AFL and AT. Distributions are often non-normal.

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  Figure 3:. Electrographic flow (EGF) metric relationships. A: Plots of every pair of metrics under study. The distribution of the individual metrics is shown above that metric along the diagonal. Plots with r2 > 0.5 are highlighted. B: Overall trendlines of the highlighted three most correlated metric pairs from A, colored by rhythm: mean flow angle variability (FAV) versus mean EGF consistency (EGFC) (r2 = 0.767; P < .0001), mean R–R correlation (R–RC) score versus disorganization score (r2 = 0.615; P < .0001), and mean FAV versus disorganization score (r2 = 0.552; P < .0001). Abbreviations: AF, atrial fibrillation; AFL, atrial flutter; AT, atrial tachycardia; CL, cycle length.

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  Figure 4:. Convolutional neural network (CNN) performance. A: Receiver operating characteristic (ROC) curve of the micro-averaged, macro-averaged, and one-versus-rest multiclass predictions for each rhythm. Atrial fibrillation (AF) is 100% separable from the organized rhythms. Area under the ROC curve (AUC) for each curve is shown in the key. B: Two-dimensional principal component analysis plot of all 156 recordings used to train and test the CNN. AF is non-overlapping with atrial flutter and atrial tachycardia.