Doppler echocardiography in cardiac tamponade: exaggerated respiratory variation in transvalvular blood flow velocity integrals.

Pulsed Doppler echocardiography has been used previously to demonstrate marked changes in transvalvular blood flow velocities during cardiac tamponade in laboratory animals and a small number of patients. To further assess the respiratory changes in transvalvular blood flow during tamponade, pulsed Doppler tracings of flow velocity profiles across all four cardiac valves were recorded during inspiration and expiration in 13 patients during cardiac tamponade, in 6 of the 13 patients after relief of tamponade by pericardiocentesis and in 8 normal control subjects. Flow velocity integrals were calculated for each valve during inspiration and expiration. In the setting of cardiac tamponade, inspiration caused an 85 +/- 46% increase in the flow velocity integral across the pulmonary valve, an 81 +/- 34% increase across the tricuspid valve, a 33 +/- 13% decrease across the aortic valve and a 35 +/- 8% decrease across the mitral valve. These phasic respiratory changes were markedly reduced after relief of tamponade (p less than 0.05 compared with tamponade) and were observed to only a minimal extent in the normal individuals (p less than 0.01 compared with tamponade). The exaggerated respiratory variations in transvalvular flow velocity integrals suggest that Doppler evaluation may be a valuable tool in the diagnosis of cardiac tamponade. Transmitral Doppler indexes of left ventricular filling during cardiac tamponade revealed that inspiration caused a shift to increased filling during late diastole, with a greater contribution of atrial systole to total left ventricular filling. These Doppler indexes did not vary significantly with respiration in the group studied after relief of tamponade or in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)