What is considered the standard criterion for a positive ST depression test?

The standard criterion for a positive ST depression test is typically defined as a change of ≥ 1.0 mm in the ST segment from baseline. This threshold is based on clinical studies and guidelines that link this specific level of ST segment depression with the presence of significant myocardial ischemia. In practice, a 1.0 mm ST segment change signifies an abnormal response to exercise and is a strong indicator that the heart may not be receiving adequate blood flow during increased physical activity.

This level of change has been validated through various research studies and is widely accepted in clinical cardiology as a reliable marker for evaluating the cardiac stress response. A higher or lower threshold, such as those referenced in the other choices, may not be as clinically significant for identifying ischemia and, therefore, would not fulfill the criteria for diagnosing a positive stress test result.