formerly_bob
The interior of the lung is lined with mucosa that creates protective barrier of mucus from the constant secretion of fluids. The rate of secretion is affected by the pressure in the capillaries. After a heart attack the output from the left and right ventricles often becomes unbalanced. When the right ventricle is stronger than the left ventricle, blood pressure in pulmonary veins increases. The increased pressure forces fluids to leak out of the mucosa at at higher rate than normal.