Hemodynamic evaluation of the left atrial appendage through Particle Image Velocimetry technique

The Left Atrial Appendage (LAA) is a small extension of the wall of the left atrium of the heart. It is particularly significant in cardiology because it is an area where blood clots can form, especially in people with atrial fibrillation. These clots can lead to stroke if they enter the bloodstream. Studies on the hemodynamics of the LAA, are important to improve clinical practices such as Left Atrial Appendage Occlusion (LAAO), a surgical technique to occlude the LAA to prevent cardioembolic stroke in atrial fibrillation patients. The two approaches are computational modeling and experimental flow measurement. The existing literature exclusively employs the PIV technique for experimental studies of fluid dynamics in vessels, such as the aorta or carotids. The LAA presents a more challenging analytical case due to its small cavity and complex geometry. This thesis employs the PIV technique to conduct experimental measurements on fluid dynamics within a patient-specific LAA model. The aim is to assess the effectiveness of LED PIV for the reconstruction of velocity fields in the LAA. In the initial phase of the experiment, a comparative study is conducted to define all variables, which are then used for measurements using the PIV technique. Images are acquired on both the longitudinal and transverse LAA planes at four depths. The images are then processed to extract the velocity field. The final analysis provides the average velocity field, along with standard deviation and correlation maps, which describe the fluid dynamics within the LAA across a cardiac cycle.