Regional Dominant Frequency: A New Tool for Wave Break Identification During Atrial Fibrillation

Figures

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  Figure 1. Block diagram of the proposed method for the regional dominant frequency (RDF) analysis and sample output of each stage.

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  Figure 2. Bipolar intracardiac electrograms (IEGMs) collected using the Reflexion™ Spiral (St. Jude Medical) catheter from a patient with persistent AF. From top to bottom, axes 1 to 10, show the bipolar IEGMs. The average of the preprocessed signals and the low-passed version of that are plotted on the 11th axis; the 12th axis shows the dominant frequency (DF) of the lowpassed signal. Subfigure (A) shows the IEGM segment with clear wavefronts; the normalized preprocessed signals (with the maximum amplitude of one) are also plotted in this sub-figure. The output of the lowpassed filter has a large peak for each wavefront and the iRDF for this subfigure varies between 4.9 and 5.5 Hz. Subfigure (B) shows another segment of the IEGM with a wave break in which there are no distinguishable wavefronts at the beginning of the segment. Here, the average of the preprocessed signal has multiple small peaks that are not present in the lowpassed version of it, and there is a significant drop in the iRDF at this time.

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  Figure 3. The instantaneous electrode dominant frequency (iEDF) and the instantaneous regional dominant frequency (iRDF) of the IEGM shown in Figure 2 when T = 1 s. The average of the iEDF of all the electrodes (shown in blue) does not drop at the same time as the iRDF, identifying different wave break (WB) instances. Green boxes mark WB instances obtained using iRDF.

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  Figure 4. (A) The Pearson correlation of the RDF(D) and RDF(30) and also the upper and lower bounds of the 95% confidence interval (CI) of the correlation as a function of segment duration D. (B) The Pearson correlation between the wave break rate (WBR) obtained using the D-second segment and the one obtained from the 50 s segment. The 95% CI bounds of the correlation are also plotted. The value in parenthesis in front of WBR or RDF shows the electrogram duration (in second) that is used to calculate corresponding feature.

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  Figure 5. Histograms of the wave break rate (WBR) in WB/s and the regional dominant frequency (RDF) in Hz, and also the scatter plot of the WBR and RDF for 258 segments with durations longer than 25 s.

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  Figure 6. The estimated values for the wave break rate (WBR) in WB/s and the regional dominant frequency (RDF) in Hz in different left atrial sites. RSPV, right superior pulmonary vein; RIPV, right inferior pulmonary vein; LSPV, left superior pulmonary vein; LIPV, left inferior pulmonary vein; LAA, left atrial appendage; RAnt, right antrum; LAnt, left antrum; PostW, posterior wall; Sept, septum; AntW, anterior wall; MitIs, Mitral Isthmus.

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  Figure 7. The prevalence of the ↑RDF-↓WBR sites at different anatomical positions in the paroxysmal and persistent patients. PVs, pulmonary veins; LAA, left atrial appendage; PostW, posterior wall; Sept, septum; AntW, anterior wall; MitIs, Mitral Isthmus.

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  Figure 8. Example of 3-dimensional atrial maps color coded based on the regional dominant frequency (RDF) and wave break rate (WBR). Four bipolar IEGMs of the catheter at a site with high RDF (7 Hz) and low WBR are shown.

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  Figure 9. (A) A 3-dimensional atrial map color coded based on the CFEmean for a patient with persistent AF; the ablation sites are marked with brown circles. (B) From top to bottom surface ECG (lead I), IEGMs of the ablation catheter placed at the location marked with star, collected from the Inquiry™ (St. Jude Medical) catheter placed in coronary sinus (CS), and from Reflexion™ Spiral (St. Jude Medical) placed in right superior pulmonary vein. (C) Atrial maps color coded based on the regional dominant frequency (RDF) and wave break rate (WBR) when 24 segments longer than 25 s are used to create these maps. In all the atrial maps, the ablation site that lead to AF termination is marked with black star.