Abnormal septal motion in cardiac tamponande with pulse paradoxus. Echocardiographic and hemodynamic observations.

In a patient with cardiac tamponade and pulses paradoxus the echocardiogram showed markedly abnormal septal motion, consisting of posterior displacement during inspiration. This displacement resulted from an increase in right ventricular size and a decrease in left ventricular volume, not attributable to a change in position of the heart. The correlation of this finding with hemodynamic events showed that the inspiratory drop in arterial pressure followed septal displacement. These observations support the hypothesis that pulsus paradoxus may be caused by competition of the ventricles for filling within a relatively rigid pericardial space. Displacement of the interventricular septum could be the mechanism by which this completition takes place.