Funding Acknowledgements Type of funding sources: None. Background Atrial fibrillation (AF) is one of the most common reasons that patients visit the emergency department (ED). During the initial investigation, many of these patients are found to have increased troponin levels and it is not clear if this could be an indicator of underlying coronary artery disease (CAD). CHA2DS2-Vasc score is widely used to estimate the thrombotic risk in patients suffering from AF. Purpose To examine any possible relation between the elevated high sensitivity troponin I (hsTnI) observed in patients with AF that visited the ED of our hospital during one year and their CHA2DS2-Vasc score with the presence of underlying CAD. Methods We recorded the patients presenting in the ED with AF for a period of 12 months and found to have elevated troponin during their initial investigation. We calculated the CHA2DS2-Vasc score and then divided the patients in two groups : Group 1 (CHA2DS2-Vasc score >4) and Group 2 (CHA2DS2-Vasc score <4). We recorded the maximum level of hsTnI.All patients underwent noninvasive investigation for coronary artery disease (SPECT or stress ECHO) and when it was indicated coronary angiogram was performed. Results We recorded 428 patients, 256 male and 172 female wit mean age 64 ±10.72 years. Group 1 included 194 patients and group 2 234. We recorded a statisticaly significant difference in the maximum levels of hsTnI between the two groups (Group 1 8742±964.8 pg/ml vs Group2 1324±85.7 pg/ml, p<0.01). In Group 1 the non invasive investigation was suggestive for coronary artery disease in 168 patients (86.8%), whereas in Group 2 in 113 (48.2%)(p<0.05). The patients with positive SPECT or stress ECHO underwent coronary angiography or coronary CT scan. Non significant disease had (Group 1 vs Group 2 ) 17/194(10.11%) vs 75/234(66.37%)(p<0.01), one vessel disease 66/194(39.28%) vs 19/234(16.81%)(p<0.05), two vessels disease 54/194(32.14%) vs 14/234(12.38%) (p<0.05) and three vessels disease 31/194(18.45%) vs 5/234(4.42%)(p>0.05). Conclusions Higher CHA2DS2-Vasc score was related with higher levels of hsTnI in patients with AF. Moreover, patients with higher CHA2DS2-Vasc score were found to have more often underlying coronary artery disease and its severity was found to be related with the higher CHA2DS2-Vasc score. More studies are needed to investigate whether it would be useful to use CHA2DS2-Vasc score when evaluating the increased levels of hsTnI in patients with AF and if it could be included in an algorithm.