Cardiology: squatting in tetralogy of Fallot: practice question

A General Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Medicine · Cardiology: squatting in tetralogy of Fallot

Sample item

A child with tetralogy of Fallot squats during play and the cyanosis eases. What is the physiological basis of this relief?

ALarger venous return widens the infundibular obstructionBSlower heart rate lengthens ventricular filling timeCLower pulmonary resistance raises pulmonary flow directlyDHigher systemic resistance reduces right-to-left shunting

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Higher systemic resistance reduces right-to-left shunting

Squatting kinks the femoral arteries and raises systemic vascular resistance, so less blood is shunted right-to-left across the ventricular septal defect and more goes to the lungs. Venous return of poorly saturated blood from the legs is also reduced.

Option by option

A. Larger venous return widens the infundibular obstruction
Increased venous return would worsen infundibular spasm and does not relieve cyanosis.
B. Slower heart rate lengthens ventricular filling time
Heart rate is not the mechanism; relief comes from the change in systemic resistance.
C. Lower pulmonary resistance raises pulmonary flow directly
Squatting does not lower pulmonary resistance; the benefit comes from the systemic side.
D. Higher systemic resistance reduces right-to-left shunting (correct)
Correct. Raised systemic resistance favours flow to the lungs and lowers the right-to-left shunt.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is D, Higher systemic resistance reduces right-to-left shunting. Squatting kinks the femoral arteries and raises systemic vascular resistance, so less blood is shunted right-to-left across the ventricular septal defect and more goes to the lungs.

Why is "Larger venous return widens the infundibular obstruction" not the answer?

Increased venous return would worsen infundibular spasm and does not relieve cyanosis.

Why is "Slower heart rate lengthens ventricular filling time" not the answer?

Heart rate is not the mechanism; relief comes from the change in systemic resistance.

Why is "Lower pulmonary resistance raises pulmonary flow directly" not the answer?

Squatting does not lower pulmonary resistance; the benefit comes from the systemic side.

What concept does this question test?

It tests Cardiology: squatting in tetralogy of Fallot in General Medicine. Venous return of poorly saturated blood from the legs is also reduced.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Cardiology: squatting in tetralogy of Fallot?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.