A STUDY OF FOSSA OVALIS : HOW THE MORPHOMETRY AND LOCATION AFFECTS TRANSSEPTAL APPROACH TO LEFT ATRIUM.

Abstract

Background- Fossa Ovalis (FO) surrounded by limbus are embryological remnants in inter atrial septum of heart. By Trans-septal approach, towards the left heart chambers, floor of FO is punctured to perform various types of diagnostic and therapeutic procedures. Variable position and morphometry of FO remains main challenge. Materials and Methods– 30 heart specimens were procured from properly embalmed cadavers. FO was Inspected in interior of the right atrium. Shapes, diameters, position of FO were determined by Vernier callipers. Probe patency test was performed in cases of Patent Foramen Ovale (PFO). occurrence of PFO is 23.3% (7 out of 30 hearts). The average Result- transverse diameter of FO was 11.68 mm and average vertical diameter was 13.70 mm. Most of the FOs ware oval with longer vertical diameter. In 26 cases (86.6%) limbus is raised and in 4 it is totally flat with the surface of IAS. In 22 hearts, wall of FO were thinner than rest of inter atrial septum (IAS). In one case Chiari strands are found in the floor of FO. Conclusion– Raised limbus of FO prevents slipping of needle while puncturing. Small FO, Chiari strands or multiple cardiac anomalies are unfavourable for TS puncture. To perform Left atrial pressure measurement, and in different cardiac surgeries proper visualization and knowledge of FO is very important.