Reversed septal motion in right ventricular volume overload: false negative sign in the presence of increased septal thickness.

Paradoxical septal motion of the interventricular septum and right ventricular enlargement constitute diagnostic features of right ventricular volume overload. A diastolic septal displacement toward the left ventricle and its systolic normalization explain this phenomenon. A thick septum would, theoretically, impede such movement. One patient with a cardiac allograft and gross tricuspid regurgitation is described who, in the context of a rejection episode and in a very short interval, showed two septal motion patterns related to two different septal thicknesses. It is concluded that in a patient with large right ventricular dimension and increased septal thickness, lack of paradoxical septal motion does not rule out severe right ventricular volume overload.