Visualization of catheter ablation for atrial fibrillation: Impact of devices and anatomy

Figure 4 Fossa ovalis manipulation during transseptal punctures. A: Deformation of the fossa ovalis at the point of needle puncture in the left atrium; B: Transseptal puncture at the time of dilator insertion, with deformation of the fossa ovalis (red oval) and a tight fit between the dilator and the fossa ovalis; C: Image of the septal ridge (red circle 1) around the fossa ovalis, the thin and highly compliant nature of the fossa ovalis (red circle 2), and the Eustachian ridge (red circle 3).