Paramedic National Registry Practice

What does ST segment depression typically indicate?

1. Ischemia

2. Injury

3. Heart failure

4. Hyperkalemia

The correct answer is: Ischemia

ST segment depression typically indicates myocardial ischemia, which occurs when there is a reduced blood flow to the heart muscle. This reduction in blood supply can happen during periods of increased demand, such as during exercise or stress, or it may be due to underlying coronary artery disease. During ischemia, the heart muscle does not receive enough oxygen, leading to changes in the electrical activity of the heart that can be detected on an electrocardiogram (ECG). ST segment depression is a manifestation of this decreased blood flow, reflecting abnormalities in the cardiac repolarization process. In contrast, ST segment elevation commonly suggests myocardial injury, representing a more acute or severe condition often associated with a heart attack. Conditions like heart failure and hyperkalemia have different ECG manifestations, and thus ST segment depression is specifically associated with ischemia. Understanding these distinctions is critical for assessing a patient's cardiac status and determining appropriate interventions.