IJCS | Volume 31, Nº6, November / December 2018

571 Figure 1 - Global left atrial strain during reservoir phase ( Ɛ R) before and after percutaneous closure of the left atrial appendage (LAA). Differences between baseline and post-LAA occlusion device implantation data were analysed by paired sample t-test. Madeira et al. Atrial appendage closure and atrial performance Int J Cardiovasc Sci. 2018;31(6)569-577 Original Article traced in end-systole in both four- and two-chamber views by a point-and-click approach. An epicardial surface tracing was then automatically generated by the system, generating the region of interest (ROI). For definition of the ROI at the discontinuity of the left atrial wall (corresponding to pulmonary veins and left atrial appendage), the limit of left atrial endocardial and epicardial surfaces at the junction of these structures was extrapolated. After manual adjustment of ROI width and shape to ensure optimal tracking, the software divided the ROI into six segments (basal, middle and apical segments of the atrial septum and lateral wall), and the tracking quality of each segment was automatically scored as either acceptable or non-acceptable, with possible further manual correction. Segments from which good quality images could not be obtained were rejected by the software and excluded from the analysis. In subjects with good quality images, a total of twelve segments were analyzed. The software displayed peak longitudinal Ɛ R and strain rate for each of the twelve segments and the average global strain. Peak Ɛ R were expressed in percentages and SR R in s -1 . Since left atrial wall strain is reliably imaged and is not constrained by other cardiac chambers, recent consensus of imaging for evaluation of atrial fibrillation patients recommend the evaluation of this parameter rather than global Ɛ R. 16 Therefore, we also performed a comparison between left atrial lateral wall strain and SR R at baseline and after device implantation. Since we included patients with atrial fibrillation and sinus rhythm, we used the first left ventricular systolic frame as the frame of interest – QRS timed analysis. LAA closure procedure LAAclosuredevicewasimplantedinthecatheterization laboratory. The device used was an Amplatzer ® (St. Jude Medical, St. Paul, Minnesota, USA) and was delivered