Abnormalities of the ST Segment

Abstract

The ST segment is the period between the cessation of the QRS complex which is marked by the J point and the onset of the T wave. In interpretation of the ST segment, the shape (concave or convex upward) and the slope are sometimes as important as the absolute degree of ST-segment elevation or depression. Associated T wave changes are also important. The large number of factors affecting the ST segment often makes interpretation difficult. In addition, the relative lack of sensitivity of the ST segment for ischemia and infarction means that clinical decisions regarding the care of a patient with suspected ischemia and/or infarction must be made on clinical grounds if the electrocardiogram is normal. Normal ST segments do not rule out ischemia, infarction, or other conditions.