In patients with acute myocardial ischemia, the ECG can show either elevated, flat or inverted T waves, or bidirectional T waves. Among them, if one wants to see whether the T waves are inverted or whether bidirectional has any significance, one needs to look at the R-wave dominated leads with symmetrical T-wave inversions known as coronal T waves, a condition that strongly suggests the presence of myocardial ischemia in the patient. In addition to this, long T-wave bidirectional inversions are usually secondary to T-wave inversions. These changes are commonly seen in patients with variant angina, or unstable angina, and are indicative of the development of acute myocardial ischemia. In addition, the presence of downward-sloping ST-segment depression and horizontal depression is also strongly suggestive of acute ischemia. If the patient has ST-segment elevation, this is seen in the setting of acute myocardial infarction or coronary vasospasm.