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
True about third hea sound is 
Select and explain. 
A. Absent in Chr. Constrictive pericarditis, B. Absent in aoic aneurysm, C. Absent in MS, D. Normal physiologically in Athletes
C: Absent in MS
Answer: C: Absent in MS 
Explanation: Answer is C (Absent in MS): Third hea sound (S3) is commonly seen in association with ventricular dysfunction. Ventricular function is usually. normal with MS and hence S3 is usually not a feature of MS. Physiological S3 may be heard in athletes, while constrictive Pericarditis and ischaemic hea disease (MI) are established causes of pathological S3.