What EKG signs indicate myocardial ischemia?

Myocardial ischemia refers to a condition where there is inadequate blood flow to the heart muscle, which can lead to chest pain and, if prolonged, can cause damage to the heart tissue. The EKG changes associated with myocardial ischemia primarily include ST segment depression and T wave inversions.

When myocardial ischemia occurs, one of the first EKG changes you may see is ST segment depression, which indicates that the heart muscle is not receiving enough oxygen during periods of increased demand. Following this, T wave inversions can occur as a secondary response to ischemia. T waves may become inverted or flattened after the initial phase of ischemia as the repolarization process of the heart is altered.

These two EKG findings (ST segment depression and T wave inversions) are critical indicators of myocardial ischemia, while other options may indicate other cardiac conditions or changes unrelated to ischemic events. For example, ST segment elevation typically suggests an acute myocardial infarction, while tall R waves and Q waves may represent prior myocardial infarctions rather than ischemia itself. Normal sinus rhythm with ectopic beats does not indicate ischemia, as it represents a different kind of cardiac rhythm disturbance.