CMR images with representative measurements at atrial end-diastole. (A) Two-chamber (2 Ch) view with left atrial (LA) length measurement. (B) Apical four-chamber (4 Ch) view with LA and right atrial (RA) 4 Ch length measurement. (C) 2 Ch view with LA endocardial border tracings. (D) 4 Ch view with LA and RA endocardial border tracings. P: Posterior. L: Left.