Novel insights in pathophysiology of postoperative atrial fibrillation

Figures

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  Programmed atrial extrasystoles enhance endo- epicardial conduction disorders.

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  Figure 1. Simultaneous endo-epicardial mapping of the RA was performed using two 128-electrode arrays secured exactly opposite of each other on 2 spatulas (left panel). Color-coded activation maps of the endo- and epicardium are shown in the middle panel. Black arrows display the main trajectories of the electrical wavefronts. To calculate EEA, for each electrode, the median time delay within the exact opposite electrode and its eight surrounding electrodes was selected. The longest time delay for every endo-epicardial electrode pair is then selected to express local degree of EEA, defined as transmural difference in electrical activation of ≥15 milliseconds between every endo-epicardial electrode pair. Ao, Aorta; SCV, superior caval vein; RA, right atrium; RV, right ventricle; ICV, inferior caval vein; Epi, epicardium; Endo, endocardium; EEA, endo-epicardial asynchrony.

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  Figure 2. Upper panel: Typical endo-epicardial activation maps of a SR beat (left) and P-AES (right) obtained from the same patient. Black arrows display the main trajectories of the electrical wavefronts and local activation times are depicted at its head and tail. Thick black lines indicate lines of conduction block. The lower panel shows the effect of programmed right atrial stimulation on the amount of conduction block (y-axis) for each patient (x-axis) separately. Increase in total activation time and amount of conduction block is observed during P-AES compared with SR. SR, Sinus rhythm; LAT, local activation times; Epi, epicardium, Endo, endocardium; P-AES, programmed atrial extrasystoles.

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  Figure 3. Upper panel: Endo-epicardial activation maps and corresponding EEA maps of one single SR beat (left) and P-AES (right) obtained from the same patient. Black arrows display the main trajectories of the electrical wavefronts and local activation times are depicted at its head and tail. Thick black lines indicate lines of conduction block. The lower panel shows the effect of programmed right atrial stimulation on the amount of EEA for each patient separately. An increase in conduction block and EEA is observed during P-AES compared with SR. SR, Sinus rhythm; LAT, local activation times; Epi, epicardium; Endo, endocardium; EEA, endo-epicardial asynchrony; P-AES, programmed atrial extrasystoles.

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  Figure 4. Left panel: This pilot study revealed that P-AES originating from the free wall of the RA (1) provoked a substantial increase in endo- and epicardial conduction disorders, (2) enhanced electrical asynchrony between both layers up to 44 milliseconds, and (3) provoked more conduction disorders and EEA in patients who developed POAF compared with patients who remained postoperatively in SR. Right panel: Typical endo-epicardial activation maps of a sinus rhythm beat (left) and programmed AES (right) obtained from the same patient are shown. Black arrows display the main trajectories of the electrical wavefronts and local activation times are depicted at the head and tail. Thick black lines indicate lines of conduction block. Enhanced electrical disturbances can be observed during programmed AES compared with sinus rhythm. These findings may explain why postoperative AES may induce POAF.