"Left Heart " Radiopotassium Dilution Curves in Patients with Rheumatic Mitral Valvular Disease

"Left heart " radiopotassium-dilution curves were carried out in 9 patients with rheumatic mitral valvular disease. From the curves, blood flow, circulation times, and "left heart " and aortic vol-umes were calculated. When this technic is used along with "left heart " pressure measurements, it appears to have a satisfactory reliability in demonstrating abnormalities of flow, volume, and mitral valve function. In theory, its proper application permits complete quantitation of these parameters. IN SOME patients having long standing rheumatic heart disease routine clinical studies are inadequate either in establishing the existence or in evaluating the severity of stenosis or insufficiency of the mitral valve. Yet corrective surgical treatment makes evaluation of mitral valve function a matter of considerable importance. The surgical pro-cedure, the surgical mortality, and the prog-nosis covering postoperative improvement are all influenced to some extent by the nature of the lesion present. A number of specialized diagnostic proce-dures have been employed to improve diagno-sis and quantify approximately the degree of the abnormalities present. Among these are an-giocardiography, ' measurement of pulmonary arterial "wedge " pressure, ' ballistocardiog-raphy,3 and direct measurement of "left heart" pressure.4 Yet, mistaken evaluations are still occasionally made or corroborative evidence is desired, particularly with respect to the amount of insufficiency present. It was con-sidered that indicator-dilution curves made by injections of an indicator into the left heart and aortic root could be used to provide additional and perhaps better information on blood flow, valve function, and also on left heart volume. The data so far available from radiopotas