IJCS | Volume 32, Nº6, November / December 2019

DOI: 10.5935/2359-4802.20190042 585 ORIGINAL ARTICLE International Journal of Cardiovascular Sciences. 2019;32(6):585-593 Mailing Address: Natália Aline da Silva Avenida Luís Pasteur, 239. Postal Code: 07909-110, Jardim Nova Belém, Francisco Morato, São Paulo, SP – Brazil. E-mail: nataliaaline.silva@hotmail.com , nataliaalinee@gmail.com Left Atrial Size Contribution to the Predictive Capacity of Two Scores for Atrial Fibrillation in the Postoperative Period of Cardiac Surgeries Natália Aline da Silva 1, 2 a nd Rita de Cássia Gengo e Silva Butcher 3 Faculdade de Medicina da Universidade de São Paulo, 1 São Paulo, SP - Brazil Escola de Enfermagem da Universidade de São Paulo, 2 São Paulo, SP - Brazil Programa de Pós-graduação em Enfermagem na Saúde do Adulto da Escola de enfermagem da Universidade de São Paulo, 3 São Paulo, SP - Brazil Manuscript received on March 01, 2018, revised manuscript on October 23, 2018, accepted on November 01, 2018. Abstract Background: Postoperative atrial fibrillation (POAF) is a common complication associated with undesirable outcomes; hence, the provision of appropriate tools is important to help identify patients at risk. Objectives: To evaluate the predictive capacity of the CHADS 2 and CHA 2 DS 2 -VASc scores, alone and combined with left atrial (LA) size, for the onset of POAF in patients undergoing coronary artery bypass grafting and/or valvular surgery. Methods: We performed a retrospective cohort study on 144 patients. A decision tree was used to identify the cut-off values of the CHADS 2 and CHA 2 DS 2 -VASc scores and LA size in order to calculate sensitivity, specificity, predictive- value positive (PVP), and predictive-value negative (PVN), in addition to regression models. The receiver operating characteristic (ROC) curve was used to estimate the accuracy of the models. The level of significance adopted was 5%. Results: Patients who developed POAF were older (p = 0.050), had reduced left ventricular ejection fraction (p = 0.045), longer hospital length of stay (p = 0,018), but their mean CHADS 2 (p = 0.077) and CHA 2 DS 2 -VASc (p = 0.109) scores were similar to those of patients with no arrhythmia. LA size improved the predictive capacity of the CHADS 2 score, in terms of specificity and PVP, and of the CHA 2 DS 2 -VASc score, in terms of sensitivity and PVN. However, the CHADS 2 (OR = 1.198; CI95% = 0.859-1.156) and CHA 2 DS 2 -VASc (OR = 1.047; CI95% = 0.784- 1.401) scores were not predictors of POAF, either alone or in combination with LA size (OR = 1.163; CI95% = 0.829- 1.648 and OR = 1.065; CI95% = 0.795-1.433). Conclusion: The CHADS 2 and CHA 2 DS 2 -VASc scores alone or in combination with LA size did not show good predictive capacity for POAF. (Int J Cardiovasc Sci. 2019;32(6):585-593) Keywords: Atrial Fibrillation; Arrhythmias, Cardiac/complications; Postoperative Complications; Cardiac Surgical Procedures. Introduction Atrial fibrillation (AF) is cardiac arrhythmia resulting from grossly disorganized atrial electrical activity, due to multiple and continuous intra-atrial reentrant circuits, characterized by impaired atrial contraction, followed by absent atrial systole. 1 Certain pathological heart conditions, such as those evolving with structural changes, or surgical manipulation of the organ, may increase the risk of developing AF. 2 Arrhythmia occurs in about 30% of patients in the postoperative of coronary artery bypass graft surgery and in up to 60% of postoperative patients submitted to concomitant valvular surgery. 3,4 The consequences of AF, especially when it is irreversible, are clearly associated with the risk of thromboembolic phenomena and mortality, affecting 11% of the elderly population, up to 30 days after the