First Evidence of Endo-Epicardial Asynchrony of the Left Atrial Wall in Humans

Figures

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  Figure 1. Pulmonary Veins Are Dissected and the Mitral Valve Is Exposed (Left) In the posterior view, pulmonary veins are dissected, and the mitral valve is exposed. The epicardial electrode array is shown on the LAA and points toward the left superior pulmonary vein (virtual in this dissected heart). The endocardial electrode array is not shown in this figure in order to maintain overview. Atrial wall thickness at the mapping location was 2 mm in this heart. (Right) In the upper panel, the endo-epicardial electrodes are fixed on a flexible spatula. The exact opposite electrodes are marked with a yellow and a red dot. The surrounding 8 electrodes are marked with squares. (Right) In the lower panel, the local activation times of directly opposite and its 8 surrounding electrodes are shown. Differences in local activation time between the reference electrode and the 9 opposite electrodes were calculated from the endo-epicardium. LA = left atrium; LAA = left atrial appendage; LV = left ventricle; MV = mitral valve.

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  Figure 2. Activation Maps of the Epi-Endocardium of 1 SR Beat Arrows indicate the main direction of the propagating wavefront, and thick black lines indicate areas of conduction block. Activation begins in the upper part of the endocardial mapping area, and the propagating wavefront is blocked in the middle of the array. The middleandlower parts of the mapping area are activated 26 and 32 ms, respectively, later, and within the following 29 ms, the whole mapped epicardial area is activated as well. Two unipolar electrograms recorded from 2 opposite electrodes show a considerable difference of 32 ms in local activation time between both layers. The maximum degree of EEA measured in this patient was 44 ms. The color-coded EEA map in the lower panel demonstrates the degree of EEA in a color and shows that EEA is present in 41% of the mapping area. EE= endo-epicardial; EEA = endo-epicardial asynchrony; ENDO = endocardium; EPI = epicardium.