Discussion
editVW review YT Critical Comments 20171221:
2 upvotes, Cited Robbins with all due respect I found couple of problems which contradict with my knowledge: 1.ostium secundum defects are caused by insufficient growth of septum secondum to occlude second ostium
Agree, for the most part, see above and also: https://www.uptodate.com/contents/classification-of-atrial-septal-defects-asds-and-clinical-features-and-diagnosis-of-isolated-asds-in-children?search=atrial%20septal%20defect&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
“Secundum defects — Secundum defects account for approximately 70 percent of all ASDs, and occur twice as often in females as in males [5-8]. Familial recurrent rate has been estimated to be about 7 to 10 percent [9,10]. A comprehensive literature review reported a median incidence of 564 per million live births [11]. However, the true incidence of secundum atrial septal defect may be substantially higher because many ASDs are commonly undiagnosed in infancy and childhood, and spontaneously resolve. (See 'Spontaneous closure' below.)
Secundum ASDs are typically located within the fossa ovalis (remnant of the foramen ovale in the right atrium). This type of ASD can result from arrested growth of the secundum septum or excessive absorption of the primum septum (figure 2). Multiple defects can be seen if the floor of the fossa ovalis is fenestrated. The defects vary greatly in size, from less than 3 mm to greater than 20 mm.” 2.paradoxical embolism these defects cannot be explained without Eisenmenger syndrome, you showed the embolus to be simply crossing over to left side. According to UpToDate it is not necessary
https://www.uptodate.com/contents/atrial-septal-abnormalities-pfo-asd-and-asa-and-risk-of-cerebral-emboli-in-adults?search=paradoxical%20embolism&source=search_result&selectedTitle=1~56&usage_type=default&display_rank=1 “Right-to-left shunting — Right-to-left shunting through a PFO or an ASD can result in a paradoxical embolus (see 'Paradoxical emboli' above).
Since a transient right-to-left atrial pressure gradient is sufficient to induce right-to-left shunting across a PFO (or atrial septal defect [ASD]), such shunts commonly occur in individuals with no significant net right-to-left shunting between the atria (ie, those with no net intracardiac shunt or with a net left-to-right shunt). Chronic elevation in right heart pressures (eg, Eisenmenger syndrome) is not required for paradoxical embolism to occur. Transient right-to-left shunting across a PFO is a dynamic phenomenon given the significant variability of both right and left atrial pressures.” 3-day old comment
Respectfully I can say that the pathophysiology has a mistake. ASD is due to a lack of tissue. Septum secundum does not grow --> leaving the ostium secundum open; occurs in the womb... This is why it is a congenital disease. This explanation is perfect for Patent Foramen Ovale and this one occurs post natally. Addressed above