ACSISs conducted in 2004, 2006, and 2008 in all the cardiology departments and coronary care units in Israel. Of the 5937 patients included in these surveys, 4060 (68.5%) had no earlier coronary interventions. Of these, complete angiographic data were available for 2903 patients who defines the study group. The rest of the patients were managed conservatively during the index hospitalization. On the basis of coronary angiography, 142 (4.9%) of the 2903 patients had no obstructive coronary artery disease (OCAD), 1895 (65.3%) had 1-2-vessel OCAD, 752 (25.9%) had 3-vessel OCAD, and 114 (3.9%) had left main disease. A comparison was made between the NONCA group and the OCAD group. When compared with the patients with OCAD, the NONCA patients were younger, more likely to be females, and had similar risk factors for OCAD. On admission, a higher incidence of chronic anticoagulants usage was noted in the NONCA group (5.6 vs. 2.0% in OCAD, P=0.04). One-quarter of the NONCA patients presented with ST-elevation on ECG as opposed to nearly half in the OCAD group (27.5 vs. 52.3% P<0.001). Most of the NONCA patients presented with normal or preserved left ventricular function on echocardiography, as compared with the significantly lower incidence of normal function in OCAD patients (77 vs. 45.5%, P<0.001).