Evaluation of Left Atrial Appendage Isolation Using Cardiac MRI after Catheter Ablation of Atrial Fibrillation: Paradox of Appendage Reservoir

Figures

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  Fig. 1. Schematic diagram showing the selection of the study population. AF = atrial fibrillation, LAA = left atrial appendage

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  Fig. 2. Catheter ablation of AF and intracardiac electrogram. Fluoroscopy (A) for catheter ablation of AF shows LAA (arrow) and ablation catheter (arrowhead). LA model (B) shows multiple dots which form ablation lines (arrow) for LAA isolation. Catheter-based-intracardiac electrogram (C) shows the local “a” wave of LAA (blue box) after the onset of the left ventricular QRS (red box). It is defined as LAA electrical isolation. LA = left atrial

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  Fig. 3. Analysis of cardiac MRI. Four-chamber (A) and two-chamber views (B) of cine MRI show two different LA areas and LA axis length for LAV. VENC-MRI (C) allows the measurement of blood flux in the LAA ostium and descending aorta. The graph (D) shows the changes in blood flux in a cardiac cycle. The blood flux of the aorta differentiates between the systolic and DP. Furthermore, the blood flux of LAA shows its peak value as LAA emptying (arrow) in the late DP. LGE MRI (E) shows thick LA walls of contrast enhancement (arrows) indicating the ablation lines. Three-dimensional LGE images (F–H) show three different grades of LA-LGE (yellow and red). DP = diastolic phase, LAV = LA volume, LGE = late gadolinium enhancement, VENC-MRI = velocity encoding MRI

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  Fig. 4. A 50-year old man without LAA isolation. The graph (A) from VENC-MRI data shows the LAA emptying (arrow) in the late DP. Two-chamber view of cine MRI (B) shows a remarkable contraction of LAA (arrow) in the DP of the left ventricle.

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  Fig. 5. A 48-year old man with LAA isolation. The graph (A) from VENC-MRI data shows the LAA emptying (arrow) in the SP. Two-chamber view of cine MRI (B) shows a weak contraction of LAA (arrow) in the SP of the left ventricle. SP = systolic phase

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  Fig. 6. Relationship between the LAA emptying flux and LAV. The graphs show the relationships between the LAA-EF, LAVmax, and LAVmin for each LAA isolation (A, B) and LAA normal activation (C, D). LAA-EF = LAA emptying flux, LAVmax = maximum LAV, LAVmin = minimum LAV