We report our experience regarding a case of left anterior accessory pathway (LAAP) catheter ablation, which finally required a retrograd approach via the left coronary sinus of Valsalva. Because of its relationship with small regions of myocardium, the sinus of Valsalva might be an important route of access during some catheter ablation procedures. Rares publications have emphasized the importance of sinus of Valsalva for LAAP ablation. Our case shows the importance of carefully mapping the whole sinus of Valsalva in cases when ablation sites are difficult to access or are unstable via trans-aortic and transseptal approaches. We also discuss the proximity of the main left coronary artery, which requires particular attention and the need to perform coronary angiography before ablation.