Carcinoid heart disease. A cardiologist's viewpoint.

In patients with malignant midgut carcinoid tumors, characteristic cardiac abnormalities can be demonstrated by cardiac ultrasound in 60-70%. These ultrasound findings include morphological and functional changes of the tricuspid and pulmonary valves, enlargement of the right heart cavities and paradoxical septal contraction pattern. In patients with severe carcinoid heart disease leading to right ventricular failure, reconstructive valvular surgery is of obvious beneficial value and should be considered when the malignant disease is under control and clinical signs of right heart failure cannot be managed medically. The pathognomonic carcinoid lesions are mainly located on the right side of the heart and consists microscopically of fibrous tissue superimposed on mural and valvular endocardium. Infiltration into underlying endocardium and myocardium has been demonstrated. The etiology of carcinoid heart disease remains obscure. The extent of the cardiac disease seems related to circulating tumor-released substances such as serotonin and tachykinins.