Vo NM, Leung M, van Rosendael PJ, et al. - As is well known, atrial fibrillation (AF) in the presence of mitral stenosis or mechanical valve prosthesis defines valvular AF, and there exist patients suffering from AF with significant native valvular heart disease (VHD) others than mitral stenosis that are grouped as nonvalvular AF, so, researchers extensively analyzed features as well as prognostic implications of these entities. This study involved 1,885 AF patients referred for electrical cardioversion, including 171 (9.1%) having valvular AF and 1,714 recognized as nonvalvular AF, of whom 329 (17.5%) were found to have significant left-sided VHD. A median follow-up of 64 months revealed more events of heart failure in patients with nonvalvular AF and with significant left-sided VHD, and higher all-cause death events in patients with valvular AF. Overall, findings revealed a relatively high frequency of AF patients with significant VHD. The results of VHD and AF on cardiac structure and function were suggested to have a greater importance, than the type of AF, as determinants of adverse outcome.