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
[{'content': 'All of the following can occur in rheumatic fever except: September 2007, 2010 \nSelect and explain. \nA. Mitral regurgitation, B. Mitral stenosis, C. Pericarditis, D. Loud first hea sound', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Loud first hea sound The mitral valve is almost always affected, sometimes together with the aoic valve; isolated aoic valve involvement is rare. Early valvular damage leads to regurgitation. Over ensuing years, usually as a result of recurrent episodes,leaflet thickening, scarring, calcification, and valvular stenosis may develop. Pericarditis may develop and commonly causes a friction rub. Myocardial inflammation leads to softening of first hea sound.', 'role': 'assistant'}]