What does an ST segment depression indicate during an exercise stress test?

An ST segment depression during an exercise stress test is indicative of potential myocardial ischemia. This occurs when there is inadequate blood flow to the heart muscle, often due to blocked or narrowed coronary arteries. In such scenarios, as the heart works harder during exercise, the demand for oxygen increases. If the heart muscle cannot receive enough oxygen-rich blood, it may lead to ischemic changes, which are reflected as ST segment depression on an electrocardiogram (ECG).

This finding suggests that the heart is not coping well under stress and raises suspicion for underlying coronary artery disease. Recognizing ST segment depression is crucial in the clinical setting, as it helps guide further diagnostic and therapeutic decisions to address the patient's cardiovascular condition effectively.