Which of the following is NOT a part of the Tetralogy of Fallot (TOF)?

AIIMS Patna NO - 2020

Child Health Nursing (Pediatrics)

Easy

Appeared in: AIIMS Patna NO - 2020

Explanation

Patent Ductus Arteriosus (PDA) is a separate congenital heart defect and is not considered one of the four classic components of Tetralogy of Fallot (TOF).
TOF is specifically defined by the presence of four concurrent defects: Pulmonary Stenosis, Right Ventricular Hypertrophy, Overriding Aorta, and Ventricular Septal Defect (VSD).
While a PDA can coexist with TOF (and may even be life-sustaining in severe cases by allowing blood flow to the lungs), it is not part of the primary diagnosis of the tetralogy.

Option B: This is incorrect because Right Ventricular Hypertrophy (thickening of the right ventricle's wall) is one of the four cardinal signs of TOF. It develops as a response to the high pressure caused by the pulmonary stenosis.
Option C: This is incorrect because an Overriding Aorta (where the aorta is positioned over the VSD) is a key diagnostic feature of TOF.
Option D: This is incorrect because Pulmonary Stenosis (narrowing of the pulmonary outflow tract) is a fundamental component of TOF and is the primary cause of the other defects and symptoms.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The four defining anatomical defects of the congenital heart condition known as Tetralogy of Fallot (TOF) as background academic context rather than a clinical decision trigger.
Recognizing the components of TOF is crucial for nurses to understand its pathophysiology, particularly the cause of cyanosis ('blue baby syndrome'). The degree of pulmonary stenosis determines the severity of the right-to-left shunting of deoxygenated blood, leading to cyanosis.
Nurses must be vigilant for 'tet spells' (hypercyanotic episodes), which are acute episodes of profound cyanosis and hypoxia in infants with TOF. Immediate nursing intervention, such as placing the infant in a knee-chest position, is critical to increase systemic vascular resistance and improve pulmonary blood flow.
What if? If the pulmonary stenosis was very mild ('pink tetralogy'), the shunt across the VSD would be left-to-right, and the infant would not be cyanotic initially. The nurse's assessment would focus on signs of heart failure from pulmonary overcirculation, rather than cyanosis.

How to Approach the Question

First, identify the negative framing of the question by spotting the word 'NOT'. This means you are looking for the option that does not belong.
Next, recall the definition of Tetralogy of Fallot. The name 'Tetralogy' itself means a group of four.
Systematically review the four classic defects associated with TOF: Pulmonary stenosis, Right ventricular hypertrophy, Overriding aorta, and Ventricular septal defect (VSD). A helpful mnemonic is PROVe.
Compare each option against the list of TOF defects.
Eliminate the options that are known components of TOF (Right ventricular hypertrophy, Over-riding of Aorta, Pulmonary stenosis).
The remaining option, Patent Ductus Arteriosus, is the correct answer as it is a separate condition, not part of the tetralogy.

Concept Tested & Keywords

Concept Tested: The four defining anatomical defects of the congenital heart condition known as Tetralogy of Fallot (TOF).
Stem keywords: Tetralogy of Fallot, TOF, heart, part of
Lead-in keywords: NOT
Negative lead-in flag: Question is negatively framed (NOT)

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