The Roentgenologic Differentiation of Lesions of the Right and Left Heart

Abstract

IN the development of the roentgen examination of the heart, the accurate determination of the size of the organ has been chiefly considered. The differentiation of the normal from the abnormal heart by the increase in transverse diameter, surface area, or volume, as demonstrated in the teleoroentgenogram, or orthodiagram, has been well established. Much less attention has been given to the increases in size, which may take place in individual chambers. While changes in the shape of the heart shadow have been widely used to determine the exact nature of the defect which is present, these have been chiefly studied in the postero-anterior projection. Lateral views which might demonstrate enlargement of the posterior chambers of the heart, the left atrium, and left ventricle, have been less emphasized, chiefly, no doubt, because of the difficulty in interpretation. Cardiac disease, with or without failure, may, for certain purposes, be classified in two broad groups: left heart lesions and right heart lesions. The former are by far the more numerous and include essentially the defects of the valves of the left heart, the aortic and mitral, and the cardiac enlargements which result from increased blood pressure. With a few rare exceptions, the diseases of the left heart are acquired lesions. It is true that mitral valvular disease affects the right heart early in its career, but the lesion originates on the left side and is properly classified as such. Right heart lesions are less common and more heterogeneous. They include disease of the pulmonic and tricuspid valves, either congenital or acquired, other congenital defects, and right heart enlargements from diseases of the lungs or of the pulmonary vessels. Such pulmonary conditions as pneumonoconiosis, asthma, emphysema, and chronic lung fibrosis may produce sufficient obstruction in the pulmonary circulation to cause hypertrophy and dilatation of the right ventricle and right auricle, with eventual right heart failure. Likewise, primary disease of the pulmonary vessels, sclerosis, and, possibly, hypertension may eventuate in the same situation. It is a common feature of all these diseases that the enlargement is confined to the right side of the heart, the left being rarely, if ever, affected, even late in the disease. Ordinarily, the distinction between those lesions which primarily affect the left ventricle, such as aortic valvular disease and hypertension, and diseases of the right heart is comparatively simple, both clinically and roentgenologically. The physical findings and the postero-anterior roentgenograms are very different in the two cases. In mitral disease, however, this differentiation is often difficult. That this is true can be borne out by anyone who has examined many cases of cardiac disease in children, in whom congenital defects are so common.