What does the presence of witnessed electrocardiographic changes during a stress test indicate?

Witnessed electrocardiographic changes during a stress test are significant because they often indicate myocardial ischemia. During a stress test, the heart is subjected to increased workloads, simulating conditions where the heart might face stress, such as physical exertion. If ischemia is present, the heart muscle does not receive adequate blood flow and oxygen, which can manifest as specific changes on the ECG, like ST-segment depression or elevation, T-wave inversions, or other abnormal rhythms.

Identifying these changes during the test is crucial for diagnosing coronary artery disease or other conditions that could lead to inadequate blood supply to the heart muscle. The ability to observe these changes in real-time helps clinicians assess the electrical activity of the heart under stress and determine the presence of underlying ischemic issues that may need further management or treatment.