ABSTRACT
INTRODUCTION The anatomy of the atrial septum is extremely variable. In patients with patent foramen ovale (PFO), the size of the defect may be as small as 2 mm on the one hand and as large as 2 cm on the other. The length of the PFO channel may be as short as 2 mm and as long as 10 mm. The thickness of the septum secundum may vary between 3 and 12 mm and variable redundancy of tissue may be the reason for a mobile, hypermobile, or aneurysmal septum primum.
