Valvular Heart Disease

Which histopathological lesion is pathognomonic for acute rheumatic carditis and is characterized by central fibrinoid necrosis surrounded by lymphocytes, plasma cells, and Anitschkow cells?

A 58-year-old man from rural India presents with progressive dyspnea on exertion and orthopnea for 3 months. He has a history of acute rheumatic fever (ARF) at age 12. On examination, he has an irregular pulse (90 bpm), elevated JVP, hepatomegaly, and bilateral ankle edema. Auscultation reveals a loud S1, opening snap at the apex, and a low-pitched diastolic murmur best heard at the apex in the left lateral decubitus position. Chest X-ray shows pulmonary congestion and straightening of the left heart border. ECG shows atrial fibrillation with a ventricular rate of 92 bpm and left atrial enlargement. What is the most likely diagnosis?

A 52-year-old man with a history of rheumatic fever presents with dyspnea and orthopnea. Echocardiography reveals mitral stenosis with an area of 1.2 cm². He is in normal sinus rhythm. What is the drug of choice for symptomatic management?

A 35-year-old woman from rural Uttar Pradesh presents with dyspnea on exertion and orthopnea. Echocardiography shows severe aortic regurgitation with aortic root dilatation. What is the most common underlying cause of aortic regurgitation in this clinical context?

Which finding best distinguishes acute rheumatic mitral regurgitation from chronic rheumatic mitral regurgitation in a 28-year-old woman presenting with dyspnea?