What is ST depression in stress test?

As a cardiovascular specialist, I can explain that ST depression during a stress test is a significant finding that can indicate the presence of coronary artery disease (CAD). Here's a detailed explanation: ST depression refers to a specific type of change seen on an electrocardiogram (ECG) during a stress test. A stress test is designed to increase the heart's workload, typically by walking on a treadmill, to see how well the heart responds to stress. The ECG records the electrical activity of the heart and can help identify potential problems. Under normal circumstances, the ST segment of the ECG trace represents the period between the end of the depolarization (ventricular contraction) and the beginning of the repolarization (ventricular relaxation) of the ventricles. When the heart is under stress, the demand for oxygen increases. If the coronary arteries are narrowed or blocked, they may not be able to supply enough oxygen-rich blood to the heart muscle, leading to ischemia. During the stress test, if there is not enough blood flow to meet the increased demand, the ECG may show an ST segment depression. This is a dip or downward shift in the ST segment that occurs during the test. It is often seen as a horizontal or downsloping depression of 1 mm (0.1 mV) or more that lasts for at least 0.08 seconds after the J point (the point of transition between the QRS complex and the ST segment). ST depression can be indicative of myocardial ischemia, which is a condition where the heart muscle is not getting enough blood flow. This is often due to atherosclerosis, where plaque builds up in the arteries, reducing the blood flow to the heart. The presence of ST depression during a stress test is a signal that further evaluation and management are necessary, as it may warrant interventions such as medication, lifestyle changes, or even surgical procedures to improve blood flow to the heart. In summary, ST depression during a stress test is a potential red flag for CAD and requires careful assessment and appropriate follow-up.

The treadmill electrocardiogram (ECG) stress test is widely used to screen for obstructive coronary artery disease (CAD). The presence of STsegment changes, either depression or elevation, on the ECG during the treadmill test often suggests presence of CAD and warrants further management.