A runner complained to his friends that he could not "get enough breath." They suggested that he talk with his doctor. After testing, the doctor suggested that he had dilated cardiomyopathy, which, as the doctor explained, results from a weakened left ventricle that can't pump out all the oxygenated blood that it receives from the lungs. What does this have to do with not "getting enough breath"?

Enlargement of ventricle resulting in back-flow of blood into the left atrium raises blood pressure in the lungs. The fluid comes out of capillaries preventing oxygenation of blood.

Explanation:

Dilated cardiomyopathy refers to the enlargement of the left ventricle. The increased size of the left ventricle does not allow it to create enough pupping action. The weaker left ventricle and resultant lower buildup of pressure lead to regurgitation of blood from the left ventricle into the left atrium via the mitral valve during ventricular systole.

The increased blood pressure in the lungs prevents diffusion of gases since the fluid comes out of blood capillaries in the lungs. Reduced oxygen supply to the body tissues of the runner makes him feel as if not getting enough breath.