This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2019, Subject name: Medicine
Which wall of the hea is enlarged first in a patient with McCallum patch? 
Select and explain. 
A. Left atrium, B. Right atrium, C. Left ventricle, D. Right ventricle
A: Left atrium
Answer: A: Left atrium 
Explanation: In MacCallum's patch the basic concept is regarding VALVULITIS (Inflammation of valves) Left atrium :enlarged first in a patient with McCallum patch