Abstract 9947: Prospective Prediction of Left Atrial Flutter From Computer Simulation

Introduction: Atypical left atrial flutter (ALAF) is often the result of ablation treatment for AF. Many patients report a reduction in quality of life from AF to ALAF. If pharmacological rate control fails additional ablation can provide solutions. However, success rates are low due to difficulties in mapping all potential flutters accurately. Hypothesis: LGE-MRI can inform computation simulation to predict all possible ALAF pathways and increase the information available to the electrophysiologist. Methods: Informed and consented patients scheduled for ALAF ablation received an MRA and LGE-MRI. Fig1. From the MRA the left atrial wall was segmented and registered to the LGE-MRI. Scar and gray areas were estimated by threshold segmentation. The threshold was calculated with the intensity value ratio. The information was integrated into a monodomain model. Ionic currents were modeled according to Courtemanche with a reduction of some conductance in fibrotic regions. To induce ALAF S1S2 pacing was done with an S1 cycle length of 600ms and S2 decreased from 250 to 170ms. Induction was tested at 10 different locations. Results were provided to the electrophysiologist. Results: Prospective prediction of the ALAF pathway for six patients was successful and the clinically observed flutter was predicted. Fig. 2) shows the value of the prediction, electroanatomic mapping was inconclusive even unable to exclude the right side. Ablation on the right side did not alter the flutter, but ablation near the mitral valve. Conclusions: We successfully predicted clinically observed ALAF pathways. The next step is to find ablation points for all predicted pathways.