Anatomy Patent formen ovale is due to failure of fusion of? A Ostium primum with Endocardial cushion B Ostium primum with Ostium Secundum C Ostium primum with Septum primum D Septum primum with septum secundum 💡 Explanation Patent formen ovale is due to failure of fusion of? ✓ Correct Answer: D. Septum primum with septum secundum