What could cause a "downsloping" ST segment depression?

Downsloping ST segment depression is most commonly associated with myocardial ischemia, particularly during stress testing. When the heart is under increased demand, such as during physical activity, the supply of oxygen to the heart muscle may be inadequate if there are any coronary artery blockages. The resulting ischemia can manifest as a downsloping ST segment on the EKG. This finding is significant because it indicates that the heart is not receiving sufficient blood supply during periods of increased workload, a key indicator for potential coronary artery disease.

In contrast, left ventricular hypertrophy typically presents with other EKG changes, such as voltage criteria rather than direct ST segment changes. Pericarditis often leads to ST segment elevation rather than depression, and the normal exercise response usually does not cause significant ST segment changes.