This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Pediatrics
Single hea sound (S2) is heard in: 
Select and explain. 
A. Transposition of great vessels, B. Ebstein's anomaly, C. Tetralogy of Fallot, D. TAPVC
C: Tetralogy of Fallot
Answer: C: Tetralogy of Fallot 
Explanation: --> Single second hea sound: It is either A2 / P2/ combination of both. Decision whether it is aoic / pulmonic / combination depends on location, intensity of S2 & clinical profile of pt Seen in: *Tetralogy of fallot --> S2 represents A2 component since pulmonic component is delayed, soft & inaudible. *Eisenmenger complex --> S2 represents combination of A2 & P2 - Thus, based on auscultation alone, it might be difficult to differentiate b/w TOF & Eisenmenger complex. History & chest X-ray can distinguish these conditions.