A new sign for the detection of tricuspid regurgitation (TR) is described. The systolic displacement of the left anterior descending (LAD) artery during coronary angiography in left anterior oblique (LAO) view was quantitatively calculated in 3 groups of 20 patients each with either TR, mitral stenosis, or normal coronary arteriograms. The mean LAD displacement in the TR group was significantly rightward compared to the other groups. Uniform rightward displacement of the lower two-thirds of the LAD had a 90% sensitivity and 90-95% specificity for the presence of TR. Such displacement is probably the angiographic counterpart of the systolic paradoxical septal displacement demonstrated by echocardiography in patients with right ventricular volume overload. There was a positive correlation between the severity of TR and the magnitude of LAD displacement. Attention to the LAD displacement on LAO view may raise suspicion of TR, and indicate its severity.