What is a common cause of ST segment depression on an EKG?

ST segment depression on an EKG is often indicative of myocardial ischemia, which occurs when there is an inadequate blood supply to the heart muscle. This lack of blood flow can result in a decrease in oxygenation to the myocardial tissue, leading to changes in the electrical activity recorded on the EKG. Specifically, during a period of stress or increased oxygen demand—such as during exercise or in the presence of coronary artery disease—myocardial ischemia may manifest as a downward shift in the ST segment.

In this context, ST segment depression reflects subendocardial ischemia more than full-thickness ischemia, which typically presents as ST segment elevation. Recognizing this change is crucial for diagnosing conditions like angina or impending myocardial infarction, guiding medical professionals in further assessment and management of the patient's cardiovascular health.