Catheter ablation is being used increasingly for the treatment of atrial fibrillation (AF), and more extensive ablations that include linear lesions on the posterior wall of the left atrium (LA) are performed today. A better understanding of the anatomic relationship between the posterior LA wall and the oesophagus is required to identify potentially high-risk areas for the application of radiofrequency energy. We hereby describe a simple method to delineate the anatomical relationship between important adjacent structures and the LA in electroanatomical mapping using plain fluoroscopy images.