Diagnosis of cardiac tamponade by echocardiography: changes in mitral valve motion and ventricular dimensions, with special reference to paradoxical pulse.

The echocardiographic findings in three patients who presented with pericardial effusion and cardiac tamponade are described. Cyclic respiratory changes affected the diastolic movement of the anterior mitral leaflet, viz., during inspiration its anterior excursion decreased in amplitude and the E-F slope diminished. This inspiratory alteration in mitral valve motion was accompanied by an increase in right ventricular dimensions and a reciprocal decrease in left ventricular dimensions. Pericardial paracentesis confirmed the presence of effusion and relieved cardiac tamponade in all the patients. Repeat echocardiography, performed in two of the patients immediately after the pericardial tap, showed that the E-F slope had become steeper and that phasic respiratory variations in the diastolic motion of the anterior mitral leaflet were no longer present. The compatibility of our observations with the theories which endeavor to explain the mechanism of the paradoxical pulse in pericardial effusion with cardiac tamponade is discussed. We suggest that the abnormalities in anterior mitral leaflet motion defined by echocardiography constitute a useful addition to the study of patients with suspected cardiac tamponade resulting from pericardial effusion.