IJCS | Volume 31, Nº6, November / December 2018

576 Madeira et al. Atrial appendage closure and atrial performance Int J Cardiovasc Sci. 2018;31(6)569-577 Original Article increased left atrial volumes and decreased left atrial emptying fractions, 15 Ɛ R, and SR R . 12 Furthermore, Sasaki et al., 30 demonstrated that left atrial peak systolic Ɛ R is independently associated with LAA dysfunction in patients with atrial fibrillation. Hence, in our population of patientswith left atrial chamber dysfunction at baseline, a reduced LAA function might also be present. Our results, along with those of Hanna et al., 29 suggest that the exclusion of the LAA does not seem to have a further impact on compromised left atrial physiology. Nevertheless, a recent study with 33 patients (20 patients with atrial fibrillation) demonstrated that LAA closure was associated with an improvement in left atrial mechanical function in a 45-day follow-up, and these changes appeared to be related to changes in loading conditions (Frank-Starling effect). 31 Despite favourable short-term outcomes, the long-term effects of an increase in left atrial volume might lead to deleterious effects, mainly in patients with sinus rhythm. We must also highlight that although there was an increase in peak atrial longitudinal strain at discharge compared to baseline, peak atrial longitudinal strain tended to be lower 45 days as compared with discharge (p = 0.08). Therefore, with a longer follow-up, peak atrial longitudinal strain might return to baseline levels as observed in our study. Most previous studies were performed in patients with sinus rhythmandevaluated left atrial function immediately after LAA closure; the long-term hemodynamic effects of this procedure in patients who are in sinus rhythm are currently not known. Although we did not find any statistically significant difference between patients with decreased and with similar left atrial reservoir function after the procedure, the former group might have better left atrial function at baseline since a lower number of patients had lower left atrial volumes, higher left atrial emptying fractions, and higher Ɛ R values, consistent with the results of the studies mentioned above. Limitations Our study has several limitations. First, this was a single-center study with a relatively small sample size. However, there is a paucity of data regarding the effects of percutaneous LAA closure on left atrial function in the literature. Second, the retrospective nature of the study limited the evaluation of additional clinical and analytical parameters. Third, although we analyzed the impact of LAA percutaneous closure on left atrial mechanics, the design of our study made the assessment of clinical outcomes impossible. Finally, most of our patients had atrial fibrillation and left atrial dysfunction at baseline. It would therefore be important to study the influence of LAA percutaneous closure on left atrial function in patients who are in sinus rhythmwith normal or slightly altered left atrial function. Further studies including large populations of patients in sinus rhythm and in atrial fibrillation are needed to provide definitive evidence of the impact of LAA occlusion not only on left atrial physiology at long term, assessed by 2D-STE, but also on clinical outcomes. Conclusion We have demonstrated that in patients with atrial fibrillation and contraindication to oral anticoagulation, percutaneous LAA closure does not have a negative effect on left atrial reservoir function in patients with permanent atrial fibrillation. Further studies with a larger population of patients are warranted to confirm this finding. Author contributions Conception and design of the research: Madeira M, Teixeira R, Costa M. Acquisition of data: Madeira M, Teixeira R, Reis L, Dinis P, Paiva L, Botelho A, Costa M. Analysis and interpretation of the data: Madeira M, Teixeira R, Reis L, Dinis P, Paiva L. Statistical analysis: Madeira M, Teixeira R, Dinis P, Paiva L. Writing of the manuscript: Madeira M. Critical revision of the manuscript for intellectual content: Teixeira R, Reis L, Dinis P, Paiva L, Botelho A, Costa M, Gonçalves L. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Faculdade de Medicina da Universidade de Coimbra under the protocol number 128 – CE - 2016.