Lung function studies were near normal and his oxygen level was adequate. Both conditions may thus lead to congestive heart failure. The differences between right and left heart failure are summarized in Table 1, along with terms common to both. Lines radiating out from the heart represent exaggerated blood vessels in patient with left heart failure. See above text for discussion.
Pulmonary edema is water in the lungs.
More specifically it is an abnormal accumulation of fluid in the smallest airways and alveoli. This fluid comes from the blood vessels surrounding the millions of alveoli. Cardiac pulmonary edema is thus one manifestation of congestive heart failure and the terms are sometimes used interchangeably. The x-ray shown in Figure 1c could be interpreted as indicating CHF or cardiac pulmonary edema, both meaning the same thing. Figure 1d shows a more classic example of cardiac pulmonary edema.