​Pathology - Mitral Stenosis

​Pathology - Mitral Stenosis
Pathophysiology 
The most frequent reason is rheumatoid arthritis, which causes the valve leaflets to calcify and stiffen fibrously. The distinctive opening snap of the calcified mitral valve is caused by vigorous opening early in diastole, and the diastolic rumble is caused by turbulent blood flow through the narrow valve. The atrial kick, which forces blood through the narrow valve, is what generates the presystolic accentuation of the murmur. Increased left atrial pressure and left atrial distention (see the huge P waves in this example) are the results of restricting blood flow from the left atrium. Pulmonary edema is the result of subsequent rises in the pulmonary venous and capillary pressures (notice the rales and crackles). Exertion and lying down at night both increase venous return, which in turn raises left atrial pressure and exacerbates pulmonary edema. Right ventricular overload is frequently the result of pulmonary hypertension, which is a long-term rise in pulmonary venous pressure. Peripheral edema and jugular vein dilatation are signs of right sided heart failure and right heart enlargement (notice the right axis deviation).