Hemodynamic studies in a case of carcinoid cardiovascular syndrome.

NUMEROUS reports of cases of malignant carcinoid associated with acquired cardiovascular abnormalities have appeared in the medical literature since this syndrome was first recognized as a clinical entity. Despite the fact that the intracardiac abnormalities characteristic of this interesting disease are almost exclusively confined to the right side of the heart, catheterization studies have only infrequently been mentioned and no truly complete hemodynamic data have been included in the case reports published to date. Of the valvular lesions encountered in the carcinoid cardiovascular syndrome, tricuspid insufficiency is the most frequently seen; right atrial tracings exemplifying this condition appear in the communications of Bjorck, Axen, and Thorson' and Sjoerdsma, Weissbach, and Udenfriend.2 However, cardiac catheterization data supporting the diagnoses of tricuspid stenosis, pulmonary stenosis, and pulmonary insufficiency, which may also occur in association with functioning carcinoid, have not come to our attention. Serotonin or 5 hydroxytryptamine (5-HT), the elaboration of which by the argentaffine cells has been generally accepted as the pathogenic agent responsible for the cardiovascular manifestations of malignant carcinoid, has been shown to produce pulmonary hypertension in animals.3 The occurrence of pulmonary hypertension in the reported cases of carcinoid cardiovascular disease, however, has not been frequent. Sparks and Towbridge4 reported that cardiac catheterization established the diagnosis of pulmonary hypertension in their case but the