Differentiating the ventricular dysfunction caused by apical ballooning syndrome (ABS) from that caused by apical involvement in an acute coronary syndrome (ACS) currently requires coronary angiography. We sought to determine if echocardiography could differentiate these two syndromes by the extent of regional left ventricular (LV) and right ventricular (RV) dysfunction. The location of the hinge point between normal and hypokinetic wall motion for both the RV and LV was blindly determined in 8 patients with ABS and in 16 patients with an initial ACS secondary to obstruction of the left anterior descending coronary artery and an associated apical wall-motion abnormality. The hinge point for each wall was expressed as the percent of the wall from the apex to the annulus that was akinetic and determined for the RV free wall, the interventricular septum, and the LV anterior, inferior, and lateral walls. The ABS group as compared with the ACS group had a significantly greater RV involvement (48 +/- 20% vs 7.3 +/- 15%, P < .0001) and LV lateral wall involvement (53 +/- 18% vs 34 +/- 11%, P = .005). However, there were no differences between these groups for the other LV walls. An RV hinge point 40% from the apex was exceeded in 7 of 8 patients with ABS but in only 1 of 13 patients with ACS (P = .0005). In conclusion, patients with ABS had significantly greater RV free wall and LV lateral wall dysfunction as compared with patients with ACS. This pattern of wall-motion abnormalities, when present, could allow for an early presumptive and noninvasive diagnosis of ABS.