Heart fibrosis. Artwork showing the heart of a patient with fibrosis, along with external and internal lung structures. Fibrosis is a condition where excess connective tissue forms, and can be due to an underlying condition or due to injuries or disorders that leave scarring in and on the cardiac muscle. This view is slightly angled to show the pulmonary blood vessels leading to the lungs. At lower centre is the upper portion of the heart, with the major blood vessels above the heart. At right, one lung is transparent, revealing the internal branching blood vessels by which blood from the heart is oxygenated. The fibrosis is here shown by the darker colour of the heart. For a healthy heart, see C006/4268.