A framework to quantify the 3d left atrium wall motion model on a patient specific basis, in atrial fibrillation patients

Atrial fibrillation (AF) is the most common, clinically significant cardiac arrhythmia. AF causes structural remodeling to the left atrium (LA) chamber and reduces the contractility of the walls of the LA and disrupts the normal blood flow within the LA chamber and consequently gives rise to thrombogenic events. Therefore, the primary goal of this study is to propose a step-by-step workflow on a patient-specific basis, which can potentially assess and quantify the global and regional impact of AF on the contractility of LA and left atrial appendage (LAA) as 90% of the clot formation happens within the LAA. To conduct this study, the analysis was performed separately for the LA and LAA. However, for both the analysis, same cohort of computed tomography (CT) dynamic imaging dataset was utilized. In the case of the LA, a standardized regionalization approach was proposed to define distinct LA regions and then in the next step, global and regional contraction parameters for the LA were defined and computed to characterize LA function. Moreover, for the LAA, a semi-automatic LAA centerline extraction technique was developed and by considering the centerline as reference, LAA global and regional parameters were assessed. Results showed the potential of the proposed methods to assess and quantify the dysfunctional global and regional LA and LAA mechanical contraction in AF patients. By computing the contraction parameters, global contraction impairment, significant dilation and regional heterogeneity in contraction were noticed in AF patients as compared to the healthy subjects. Additionally, irregular and asynchronous contraction between different LA regions was also noticed in AF patients. In conclusion, the computed patient-specific contraction indices of LA and LAA were found to have the capabilities to identify and quantify global and regional contraction dysfunctionalities in AF patients.