Interpreting cardiac catheterization data. Part 2.

Data obtained by cardiac catheterization, properly interpreted, are an extremely useful supplement to information obtained from the medical history, physical examination, electrocardiography, chest x-ray examination, and other noninvasive diagnostic techniques. Elevations of pressure in the cardiac chambers and great vessels and corresponding patterns of pressure curves are discerned in the presence of various pathologic conditions affecting the heart. Blood samples are taken during cardiac catheterization for measurement of cardiac output and to detect intracardiac shunting. Attempts have been made to estimate the magnitude of shunts from abnormal dye-dilution curves. Exercise stress is often used during cardiac catheterization to evaluate overall cardiovascular performance. Angiocardiography gives a permanent graphic record of structural abnormalities. Myocardial lactate metabolism provides a means of evaluating the adequacy of coronary blood flow.