Cardiac physiology: heart sounds: practice question

A Physiology 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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Physiology · Cardiac physiology: heart sounds

Sample item

A 68-year-old man with long-standing hypertension and left ventricular hypertrophy has a presystolic gallop heard just before the first heart sound. What produces this sound?

AClosure of the aortic and pulmonary valvesBForceful atrial contraction against a stiff, non-compliant ventricleCClosure of the mitral and tricuspid valvesDRapid passive ventricular filling in early diastole

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

The answer and the reasoning

B. Forceful atrial contraction against a stiff, non-compliant ventricle

The fourth heart sound occurs in late diastole when the atrium contracts forcefully to fill a stiff, hypertrophied ventricle, so it is absent when there is no atrial contraction, as in atrial fibrillation. The third heart sound occurs in early diastole during rapid filling. S1 and S2 arise from valve closure.

Option by option

A. Closure of the aortic and pulmonary valves
Semilunar valve closure produces the second heart sound.
B. Forceful atrial contraction against a stiff, non-compliant ventricle (correct)
Correct. S4 is caused by atrial systole into a poorly compliant ventricle.
C. Closure of the mitral and tricuspid valves
The atrioventricular valve closure produces the first heart sound, not a presystolic gallop.
D. Rapid passive ventricular filling in early diastole
Rapid early filling causes the third heart sound, heard after S2.

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 Physiology question

What is the answer to this Physiology question?

The best answer is B, Forceful atrial contraction against a stiff, non-compliant ventricle. The fourth heart sound occurs in late diastole when the atrium contracts forcefully to fill a stiff, hypertrophied ventricle, so it is absent when there is no atrial contraction, as in atrial fibrillation.

Why is "Closure of the aortic and pulmonary valves" not the answer?

Semilunar valve closure produces the second heart sound.

Why is "Closure of the mitral and tricuspid valves" not the answer?

The atrioventricular valve closure produces the first heart sound, not a presystolic gallop.

Why is "Rapid passive ventricular filling in early diastole" not the answer?

Rapid early filling causes the third heart sound, heard after S2.

What concept does this question test?

It tests Cardiac physiology: heart sounds in Physiology. The third heart sound occurs in early diastole during rapid filling. S1 and S2 arise from valve closure.

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 Cardiac physiology: heart sounds?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.