This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiomyopathy & Pericarditis, Subject name: Medicine
All are features, seen in cardiac tamponade, EXCEPT: 
Select and explain. 
A. Raised JVP, B. Pericardial effusion, C. Rapid y descent, D. Pulsus paradoxus
C: Rapid y descent
Answer: C: Rapid y descent 
Explanation: Ans. is 'c' i.e. Rapid y descent In cardiac tamponade 'y ' descent is absent or slow. Rapid 'y ' descent is seen in constrictive pericarditis. Though Kussmaul sign is usually a feature of constrictive pericarditis, it can also be seen (rare) in tamponade. Distinguishing Features between Cardiac Tamponade and Constrictive Pericarditis Tamponade Constrictive Pericarditis Clinical * Pulsus paradoxus* Common Usually absent * Jugular veins * Raised JVP Present Present * Prominent Y descent* Absent Present * Prominent X descent* Present Absent * Kussmaul's sign* Rare Present * Third heart sound* Absent Absent * Pericardial knock* Absent Often present ECG * Electrical alternans* May be present Absent Echocardiography * Thickened pericardium* Absent Present * Pericardial calcification* Absent Present * Pericardial effusion* Present Absent * RV size Usually small Usually normal