This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
S4 is not seen in : 
Select and explain. 
A. Ventricular aneurysm, B. Mitral regurgitation, C. Hyperophic cardiomyopathy, D. Hypeension
A: Ventricular aneurysm
Answer: A: Ventricular aneurysm 
Explanation: Answer is A (Ventricular aneurysm) In ventricular aneurysm the ventricle becomes more compliant than normal and offers lesser resistance to .filling and hence no S4 is heard. S4 is characteristically absent in ventricular aneurysm due to increased ventricular compliance. Fouh hea sound (Sa Is low pitched, presystolic sound, produced in ventricle during 2"d rapid filling phase. It is associated with effective atrial contraction. It occurs when there is increased resistance to ventricular filling due to diminished ventricular compliance