Doppler echocardiography in pericardial disease.

In conclusion, an understanding of the physiology of cardiac tamponade and pericardial constriction allows accurate interpretation of the changes in SVC and transatrioventricular valve Doppler flow velocities that characterize each abnormality. Meticulous attention to detail in obtaining the studies is essential for accurate diagnosis, because relative changes in flow velocities during respiration may be obscured or misinterpreted if poor-quality data are obtained. In our laboratory, SVC Doppler studies have proved to be the most technically feasible in patients with cardiac tamponade, but transvalvular studies provide important complementary data and are critical in constrictive pericarditis. Hepatic vein Doppler offers an alternative approach to the analysis of systemic venous return, particularly in stable patients with dilated hepatic veins. These studies must always be interpreted with attention to possible confounding variables such as previous pericardiotomy, significant tricuspid regurgitation, severe chronic lung disease, or restrictive cardiomyopathy. As physiologic rather than anatomic indicators, they are a valuable addition to echocardiography in assessing the hemodynamic significance of pericardial abnormalities.