IJCS | Volume 31, Nº6, November / December 2018

570 Madeira et al. Atrial appendage closure and atrial performance Int J Cardiovasc Sci. 2018;31(6)569-577 Original Article hemodynamics. 8 The appendage is more compliant than the left atrium, acting as a reservoir to attenuate the rise in intra-atrial pressure in response to various hemodynamic factors. 9 Surgical clamping or removal of the LAA has been shown to cause an immediate increase in left atrial pressure, left atrial size, and pulmonary- and mitral-inflow velocities. 10 However, both the relative contribution of appendage distensibility to the passive elastic-chamber properties of the left atrium and the physiological and hemodynamic importance of the LAA are currently uncertain. Furthermore, the influence of the LAA occlusion device on left atrial performance has not yet been defined. Two-dimensional speckle-tracking echocardiography (2D-STE) is a recently developed, angle-independent, semiautomated technique used to evaluate the myocardium. 11 It uses standard B-mode images to track blocks of speckles from frame to frame, and measures myocardial lengthening and shortening relative to the baseline – the Lagrangian method. 2D-STE provides local myocardial information fromwhich displacement, velocity, strain, and strain rate can be derived, allowing an accurate assessment of longitudinal, radial, and circumferential myocardial mechanics. 11 In recent years, left atrial mechanics have been used as a surrogate for left atrial performance, which is influenced by the left atrial wall properties, left atrial volume, and left atrial pressure, and also by the left ventricular longitudinal systolic function. 12 Measurements of left atrial strain ( Ɛ R) and strain rate (SR R ) during the reservoir phase can be used to describe atrial function physiology and are sensitive to detect early functional remodeling before anatomical changes occur. 12,13 We hypothesized that left atrial function, assessed by echocardiographic parameters and 2D-STE, would decrease after percutaneous LAA closure. Therefore, our aimwas to evaluate the influence of the LAA closure device on left atrial physiology. Methods Patients Twenty-five patients with non-valvular atrial fibrillation and a high risk for stroke with a CHA 2 DS 2 - VASc Score of ≥ 1 admitted to our centre for percutaneous LAA closure between August of 2010 and August of 2015 were enrolled in this retrospective study. Nine patients were excluded due to lack of adequate echocardiographic evaluation before or after the procedure or poor echocardiographic window for the evaluation of left atrial mechanics. Referral indications for percutaneous LAA closure were contra-indication for long-termoral anticoagulation, bleeding events during oral anticoagulation, labile international normalized ratio (INR) or embolic events despite proper anticoagulation. Clinical data included past medical history, current medication, the CHA 2 DS 2 -VASc and HAS-BLED scores, and diagnostic evaluation by routine laboratory testing, electrocardiography, and echocardiography. Sixteen patients with good echocardiographic window for assessment of the left atrial mechanics were included in our study. The study was approved by the ethics committee of our institution. Echocardiographic evaluation Echocardiography was performed on the day before and 3 months after percutaneous closure of the LAA. Echocardiographic examinations were performed using an ultrasound system (Vivid 7, General Electric ® , Horten, Norway) and tissue harmonic imaging at 1.7/3.4 MHz. A complete echocardiographic study was performed using standard views according to current guidelines. 14 Three consecutive heart cycles were acquired for quantification of the left atrial size and 2D-STE analysis for sinus rhythm patients, and five consecutive heart cycles were obtained for atrial fibrillation patients. Left atrial volume was assessed by the biplane method of disks from the apical 4- and 2-chamber views and the measurements were indexed to the body surface area according to established recommendations. 15 Minimum left atrial volume was measured at left ventricular end- diastolic volume, and maximum left atrial volume at end-systole. Left atrial emptying fraction was calculated as (maximum left atrial volume - maximum left atrial volume)/ maximum left atrial volume. 15 The 2D-STEmethodwas used to calculate regional and global longitudinal Ɛ R and SR R (Figure 1). A minimum frame rate of 60 frames/sec was required for a reliable operation of the program. The recordings were processed using an acoustic-tracking dedicated software (EchoPAQ 9.0, GE Healthcare ® , Horten, Norway), which allowed for an off-line semi-automated analysis of speckle-based strain. Left atrial endocardial surface was manually