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Key Clinical Updates in Atrial Septal Defect & Patent Foramen Ovale

The 2020 ESC guidelines add the PVR to their criteria and consider it a class IIa indication if the PVR is between 3 Wood units and 5 Wood units, and the guidelines preclude the use of closure if the PVR is ≥ 5 Wood units.

ESC guidelines favor bringing the patient back to the catheterization laboratory for retesting on pulmonary vasodilators, rather than using acute testing, to see if the PVR can be reduced below 5 Wood units.

The ESC guidelines also suggest considering fenestrated closure in the face of pulmonary hypertension.

The use of bosentan or sildenafil is recommended if the PVR is over 5 Wood units and there is a right to left shunt.

A 2020 update from the guideline subcommittee of the American Academy of Neurology reaffirms no change in the policy that states patients < 55 years with cryptogenic stroke/TIA and no other identifiable cause except for the presence of a PFO should still be considered for PFO closure.

The presence of a “floppy atrial septum - atrial septal aneurysm” has been associated with a higher risk of recurrent stroke/TIA in patients with cryptogenic stroke/TIA.


  • Often asymptomatic and discovered on routine physical examination.

  • With an ASD and left-to-right shunt: RV lift; S2 widely split and fixed.

  • Echocardiography/Doppler is diagnostic.

  • ASDs should be closed if there is evidence of an RV volume overload regardless of symptoms.

  • A PFO, present in 25% of the population, rarely can lead to paradoxical emboli. Suspicion should be highest in patients who have cryptogenic stroke before age 55 years.


Knowing how the atrial septum develops embryologically helps in understanding the different anatomic lesions that create a communication between the atria (eFigure 10–19). Embryologically, the septum primum separates the two atria, first moving inferiorly toward the endocardial cushions. The ventricular septum forms by moving upward from the ventricles to the endocardial cushions at the same time. If the atrial septum does not make it all the way, the residual defect in the septum primum (ostium primum) results in the primum ASD. If the septum primum makes it all the way to meet the ventricular septum, a hole or holes (fenestrations) form in the middle of the septum (creating the ostium secundum). A second septum then moves down the right side of the first and normally covers the ostium secundum hole. If it does not cover the hole or holes, a secundum ASD is present. The septum secundum normally completely covers the right side of the atrial septum except for an oval defect in it inferiorly (the foramen ovale). After birth, the returning blood from the lungs increases the left atrial pressure and the two septi fuse in 75% of the population. If the septae do not fuse, a patent path from the RA to the LA persists (the PFO). The ...

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