CARDIOLOGY 2

A 38-year-old Asian immigrant presents for the evaluation of exertional dyspnea with minimal activity. His past medical history is significant for acute rheumatic fever. He denies any fever, chest pain, cough, malaise or weight loss. His PR: 70/min and regular; BP: 126/76mmHg; Temperature: 37.2C(99F). His apex beat is tapping and non-displaced. Auscultation of his lungs shows crepitations in both lower lung fields. Auscultation of heart reveals a loud first heart sound, mid-diastolic rumbling and a low-pitched murmur at the apex with an opening snap. The murmur is accentuated by mild exercise. Chest X-ray shows straightening of the left border of the heart and presence of Kerley B lines. EKG shows left atrial enlargement. Which of the following findings is a hallmark of the suspected disease?
A. Left atrial enlargement
B. Elevated left atrioventricular pressure gradient
C. Wide pulse pressure
D. Elevated left ventricular diastolic pressure
E. Atrial fibrillation

Explanation:
The hallmark finding of MS is elevated left atrioventricular pressure gradient that ultimately leads to left atrial enlargement. The elevated left atrial pressures are transmitted to the pulmonary veins, capillaries, and arteries. These phenomena are responsible for the exertional dyspnea and later, pulmonary hypertension and right heart failure. Enlargement of the left atrium predisposes to the development of atrial fibrillation which is quite common in mitral stenosis but is not the hallmark finding.

The left ventricular diastolic pressure is normal in pure mitral stenosis. These pressures become elevated when there is coexistent mitral regurgitation, aortic valve disease, systemic hypertension, or coronary artery disease.

A wide pulse pressure is not a feature of mitral stenosis. It occurs in aortic insufficiency and other conditions in which circulation is hyperdynamic.