Failure of foramen ovale to close will lead to?

Appeared in: JSSH Staff Nurse - 2019

Explanation

The foramen ovale is a fetal shunt located in the septum between the right and left atria.
Its purpose is to allow oxygenated blood from the placenta to bypass the non-functional fetal lungs and go directly to the systemic circulation.
After birth, increased pressure in the left atrium normally causes this flap-like opening to close permanently.
When the foramen ovale fails to close, it leaves a persistent opening between the atria, which is classified as an Atrial Septal Defect (ASD).
Specifically, this type of ASD is often called a patent foramen ovale (PFO).

Option A: Patent Ductus Arteriosus (PDA) results from the failure of the ductus arteriosus to close. The ductus arteriosus is a different fetal shunt that connects the pulmonary artery to the aorta.
Option B: Transposition of the Great Arteries (TGA) is a cyanotic congenital heart defect where the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. It is a structural malformation, not a failure of a fetal shunt to close.
Option D: A Ventricular Septal Defect (VSD) is a hole in the interventricular septum, the wall that separates the two lower chambers (ventricles) of the heart. The foramen ovale is located in the atrial septum.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Congenital heart defects resulting from failure of fetal shunt closure as background academic context rather than a clinical decision trigger.
Most small ASDs or PFOs are asymptomatic and may go undetected until adulthood.
A classic sign on auscultation for a significant ASD is a wide, fixed splitting of the second heart sound (S2).
A major risk associated with a PFO, even if small, is paradoxical embolism. A blood clot from the venous system can pass through the PFO into the arterial circulation, potentially causing a stroke.

How to Approach the Question

First, identify the key anatomical structure in the question: the 'foramen ovale'.
Recall the location and function of the foramen ovale in fetal circulation. It is an opening in the septum between the atria.
Consider the consequence of this specific structure failing to close after birth. A persistent opening in the atrial septum is, by definition, an atrial septal defect.
Evaluate the options based on this understanding.
Eliminate 'Patent ductus arteriosus' as it relates to the ductus arteriosus, not the foramen ovale.
Eliminate 'Transposition of great arteries' as it's a malformation of the aorta and pulmonary artery.

Concept Tested & Keywords

Concept Tested: Congenital heart defects resulting from failure of fetal shunt closure.
Stem keywords: foramen ovale, failure to close
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 2 (215-514) pp. 2, 1

E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 25-33

Practise the full JSSH Staff Nurse - 2019

Attempt every question from this paper in a timed mock, then review the full solution for each one.