RESUMEN
We report a case of nonsyphilitic isolated coronary ostial stenosis of the left main coronary artery observed by transesophageal echocardiography(TEE) in a 52-year-old woman with angina. The lesion was suspected during coronary angiography and it was not visualized by transthoracic echocradiography. Coronary ostial stenosis, which is potentially lethal as left main coronary artery disease, occurs rarely in the absence of other coronary artery disease. The diagnosis of ostial stenosis has been usually made by the use of coronary angiography, however, it may be difficult to diagnose at angiography if angiographic catheter is positioned across the stenotic lesion, and the unexpected serious complication during coronary angiography in such a patient may happen. The new ultrasonic imaging technique of TEE provides more detailed images of proximal coronary anatomy and coronary blood flow.