Heart in cardiac fibrosis. Coloured 3D transoesophageal ultrasound image of the heart of a 70-year-old male patient with cardiac fibrosis (valvulopathy). Cardiac fibrosis is an abnormal thickening of the heart valves. It may be due to abnormal proliferation of cardiac fibroblasts, but more commonly refers to the excess deposition of extracellular matrix in the cardiac muscle. Here, the cardiac valves (aorta, mitral and tricuspid valve ports) can be seen.