Atrial slow conduction develops and dynamically expands during premature stimulation in an animal model of persistent atrial fibrillation

Figures

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  Fig 1. Preparation of the heart for the optical mapping. The X marks the mapped area. At the edges of the mapped region, the pacing wires are show at the 4 locations: top (Aorta), bottom (Towards AV groove), left (Left atrial appendage), and right (towards pulmonary veins).

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  Fig 2. Processing of the recorded images. From left to right, (A) first the normalized and filtered recording, (B) then converted to local activation times, (C) the conduction velocity, (D) finishing with the thresholding of conduction velocity (less than 0.2 m/s). (E) Connected components marked in different colors.

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  Fig 3. (A) The percentage of observed slow conduction in the region of interest. In control conditions, the premature excitation has a minor change, whereas for animals with a history of persistent atrial fibrillation, the change is significant. The expected increase in slow conduction regions between control and persistent AF animals is significant. (B) Description of the Boxplot used through the manuscript. The interquartile range (IQR) is from 25% to the 75% of all observed values. The upper whisker is defined as the largest observation which is smaller than IQR ⋅ 1.5+ (75 percentile of observed data). Similar, the lower whisker is the smallest observation that is larger than −IQR ⋅ 1.5+ (25 percentile of observed data). Observations that are not contained between the upper and lower whisker are considered an outlier. Boxplots are created with the LATEX package pgfplots. (http://pgfplots.sourceforge.net/).

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  Fig 4. The number of slow conduction regions. (A) grouped by the type of paced beat and (B) by the position of the pacing electrode. The premature excitation does not change the number of slow conduction regions. Not all pacing positions result in the same number of slow conduction regions, however, the pacing position is not a significant factor.

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  Fig 5. Means size of slow conduction area. (A) A significant difference between control and persistent atrial fibrillation animals was detected. However, within each class, premature beats do not significantly change the size.(B) Effect of the pacing position on the mean area size. The bottom and right positions appear similar in persistent AF animals, as do the left and top positions.

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  Fig 6. Local activation times showing unidirectional conduction block. A line of blockage in the lower half is observed (dashed line) when pacing from the bottom (A) and (B). In response to a premature beat (B) an additional line of blockage develops spanning the field of view at about 45 degrees. In comparison, pacing from the left in physiological (C) or premature (D) condition does not show a significant blockage.