Fifty consecutive patients referred to a coronary care unit for acute anterior myocardial infarction with ST-segment elevation underwent coronary arteriography, left ventricular (LV) angiography, and revascularization. Transthoracic echocardiography was systematically performed using fundamental imaging, second harmonic imaging, and contrast agents to assess the LV chamber. Six patients (12%) presented with a confirmed LV mural thrombus. Thirty-five percent of patients with time to revascularization>3 hours presented with an LV mural thrombus versus 0 patients with time to revascularization<or=3 hours (p=0.003). The most accurate method of detecting LV mural thrombus was contrast echocardiography regardless of physician experience. No patient with a misdiagnosis of thrombus had an optimal acoustic window using fundamental imaging or second harmonic imaging. In conclusion, patients presenting with acute anterior myocardial infarction could benefit from contrast echocardiography for assessment of LV mural thrombus when acoustic windows are suboptimal and time to revascularization is >3 hours.