Carcinoid Heart Disease

The association between heart lesions and metastasizing carcinoid tumours is now well known. The first description of this syndrome reported in England is that of Cassidy (1930, 1931) although the author did not appreciate the nature of the liver metastases and their connection with the pulmonary valve stenosis. Similar observations were made by Biorck et al. (1952), by Isler and Hedinger (1953), and by Rosenbaum et al. (1953). It was Waldenstrom and Ljungberg in 1953 who suggested that secretion of 5 hydroxy-tryptamine (5 H-T; serotonin; enteramine) by metastases in the liver might cause the lesions in the right side of the heart. Detailed studies by Thorson et al. (1954) and by Waldenstrom and Ljungberg (1955) established that in patients with the carcinoid syndrome there is an increase in the circulating 5 H-T which is derived from the tumour deposits in the liver, and that this substance is present in higher concentrations in the right heart blood than in the systemic circulation. 5 H-T is known to be largely inactivated in its passage through the lungs An inactive breakdown product, 5 hydroxy-indole acetic acid (5 H.I.A.A.) is formed and passes into the general circulation and is excreted in the urine: it can be measured by the methods of Udenfriend et al. (1955), and of