This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
'Square root' sign is characteristic of 
Select and explain. 
A. Dilated cardiomyopathy, B. Restrictive cardiomyopahty, C. Constrictive pericarditis, D. Contractile dysfuncation seen in which type of cardiomyopathy?
C: Constrictive pericarditis
Answer: C: Constrictive pericarditis 
Explanation: square root sign is a charecteristic feature of Constrictive pericarditis Dip & plateau pattern' or 'square root sign': Early diastolic filling of the ventricles is unimpeded and abnormally rapid, but late diastolic filling is abbreted and halts abruptly when total cardiac volume expands to the volume limit set by the stiff pericardium Ref Harrison 20th edition pg 1436