Cineangiocardiographic Studies of the Origin of Cardiovascular Physical Signs

THE contraction of the cardiac muscle is responsible for the movement of blood within the heart, alterations in the shape of the heart, and the movement of the heart within the chest. The cardiac physical signs are related to one or more of these consequences of the contraction and relaxation of cardiac muscle. Cardiac catheterization pro- vides information about the pressures within the heart, and the measurement of cardiac output determines flow over several cardiac cycles, but these technics are not completely satisfactory for the study of the production of physical signs. For this purpose, measurements of pressure should be supplemented by contin- uous measurements of flow from chamber to chamber within the heart, volume, and the ex- terior shape and position of the heart. Unfortu- nately, these ideal circumstances cannot be achieved in man, but radiologic technics provide a fair approximation of this ideal. Cineangiocardiograms obtained at 60 frames per second provide enough information about the movements of the heart during each car- diac cycle to be of value in the study of the origin of physical signs. Intracardiac pressure and sound can be recorded and correlated with cineangiocardiography, which provides temporal information about the flow of blood through the heart and great vessels during a single cardiac cycle. Though instantaneous flow is not measured in absolute terms, it is possible with accuracy to time the onset of flow into a chamber or great vessel. In many