XML Template (2014) [18.3.2014–2:43pm] [1–8] //blrnas3/cenpro/ApplicationFiles/Journals/SAGE/3B2/AANJ/Vol00000/140063/APPFile/SG-AANJ140063.3d (AAN) [PREPRINTER stage] Original Article Factors associated with atrial fibrillation in rheumatic mitral stenosis Leili Pourafkari 1 , Samad Ghaffari 1 , George R Bancroft 2 , Arezou Tajlil 1 and Nader D Nader 2 Abstract Background: Atrial fibrillation is a complication of mitral valve stenosis that causes several adverse neurologic out- comes. Our objective was to establish a mathematical model to predict the risk of atrial fibrillation in patients with mitral stenosis. Methods: Of 819 patients with mitral stenosis who were screened, 603 were enrolled in the study and grouped according to whether they were in sinus rhythm or atrial fibrillation. Demographic, echocardiographic, and hemodynamic data were recorded. Logistic regression models were constructed to identify the relative risks for each contributing factor and calculate the probability of developing atrial fibrillation. Receiver operating characteristic curves were plotted. Results: Twohundred (33%) patients had atrial fibrillation; this group was older, in a higher functional class, more likely to have suffered previous thromboembolic events, and had significantly larger left atrial diameters, lower ejection frac- tions, and lower left atrial appendage emptying flow velocity. The factors independently associated with atrial fibrillation were left atrial strain (odds ratio ¼ 7.53 [4.47–12.69], p < 0.001), right atrial pressure (odds ratio ¼ 1.09 [1.02–1.17], p ¼ 0.01), age (odds ratio ¼ 1.14 [1.05–1.25], p ¼ 0.002), and ejection fraction (odds ratio ¼ 0.92 [0.87–0.97], p ¼ 0.003). The area under the curve for the combined receiver operating characteristic for this model was 0.90  0.12. Conclusion: Age, right atrial pressure, ejection fraction, and left atrial strain can be used to construct a mathematical model to predict the development of atrial fibrillation in rheumatic mitral stenosis. Keywords Atrial fibrillation, Logistic models, Mitral valve stenosis, Rheumatic heart disease, Risk factors Introduction The most common etiology for mitral stenosis (MS) is rheumatic heart disease. Despite its decreased incidence in developed countries, rheumatic heart disease remains a major problem in the developing world. MS can be complicated by atrial fibrillation (AF) which affects approximately 40% of patients with this disorder. AF predisposes patients with MS to thromboembolic events. 1 The occurrence of AF in MS is multifactorial in nature. Elevated levels of high-sensitivity C-reactive protein and N-terminal brain natriuretic peptide pre- cursors are reported in affected patients. 2,3 Studies have evaluated the influence of echocardiographic and catheterization findings in patients with AF, but the results have been inconsistent. 4–6 The stagnant blood flow in the left atrial appendage (LAA) that occurs in the absence of forcible atrial contraction during fibrillation initiates the clot-forming processes and leads to the development of arterial thromboembolic events in MS patients. 7–10 The prognosis of MS patients with thromboembolic stroke is poor, and their quality of life and functional status are often more limited by neurologic deficits than by the symptoms of MS. Therefore, it is important to identify the factors that predispose MS patients to developing AF, which may help clinicians better manage susceptible patients. Asian Cardiovascular & Thoracic Annals 0(0) 1–7 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314530134 aan.sagepub.com 1 Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 2 Department of Anesthesiology, University at Buffalo, Buffalo, NY, USA Corresponding author: Nader D Nader, MD, PhD, FCCP, Department of Anesthesiology, Main Campus 252 Farber Hall, Buffalo, NY 14214, USA. Email: nnader@buffalo.edu