Cardioangiography

Cardioangiography (roentgenography following direct cardiac injection of a radiopaque medium) is a new and experimental method which, if successful, may advance our diagnostic abilities in heart disease. Angiocardiography (indirect cardiac injection by the venous route) is now a common practice for evaluation of some specific cardiovascular anomalies, but it is not altogether satisfactory. In 1951, Sussman and Brahms (11) made a rather critical analysis of angiocardiography, calling attention to certain technical difficulties of the procedure and to anatomical and physiological factors which interfere with interpretation of the results. Of the shortcomings which they mention, the one with which we are chiefly concerned here is the poor delineation of the left ventricle and its outflow tract, as a result of which angiocardiographic diagnosis of subaortic stenosis is usually unsuccessful. That angiocardiography is not without risk is indicated by the report, by Dotter and Jackson (3), of a collected series of 26 deaths in 6,824 angiocardiographic examinations. It was learned, by analysis of these cases, that the mortality was independent of the nature of the contrast medium, the number of the injections, premedication, or general anesthesia. The death rate was higher in children, in patients with congenital heart disease, and in patients receiving large doses of the medium. Though the mechanisms of death were difficult to substantiate in the absence of positive findings at autopsy, they appeared to be due not to allergic reaction but usually to sudden respiratory arrest following the injection of the medium. It is apparent that, radiographically speaking, the most desirable method for visualizing the heart calls for the injection of as large a bolus of as dense a medium as possible in the shortest possible time. This accomplishment depends directly upon the size of the opening of the channel carrying the medium, the distance from the site of the injection to the cardiac chamber, and the force of the injection. Sutton et al. (12) pointed out the great advantage in by-passing the venous blood entering the heart by direct injection of the right auricle through a jugular vein catheter. The introduction of a radiopaque medium immediately into the right auricle improved visualization of both the right and the left sides of the heart. The idea of injecting contrast media directly into the heart by one means or another must have occurred to many investigators. The introduction of catheters of various sorts into the right side of the heart and the retrograde threading of a catheter through the aortic valve and into the left ventricle have been used for this purpose. The trauma of cardiac puncture at first thought might seem unduly hazardous. Yet it is well known that for many years physicians have been injecting adrenalin and other substances directly into the heart as a means of cardiac resuscitation.