How does myocardial ischemia typically show up on an EKG?

Myocardial ischemia is a condition where there is inadequate blood flow to the heart muscle, which can result in various changes on an electrocardiogram (EKG). One of the hallmark signs of myocardial ischemia is ST segment depression. This occurs when there is a significant imbalance between the oxygen supply and demand in the myocardial tissues, leading to fatigue and a specific electrical behavior in the heart.

When ischemia occurs, you may see a downward deflection in the ST segment, which is reflective of subendocardial ischemia. This typically appears during exercise or stress testing or may be present at rest in more severe cases. Recognizing ST segment depression on an EKG is crucial for diagnosing conditions like angina or more serious coronary artery disease.

While ST segment elevation can indicate acute myocardial infarction rather than ischemia, prolonged PR intervals and flat P waves pertain to different types of electrical conduction issues rather than ischemic changes. Understanding these nuances helps in accurately interpreting EKGs and diagnosing cardiac conditions effectively.