As a medical professional with expertise in cardiology, I can provide you with an overview of the electrocardiogram (ECG) changes that are indicative of myocardial ischemia.

Myocardial ischemia occurs when there is a lack of oxygen-rich blood flow to the heart muscle, which can lead to chest pain or angina. The ECG is a crucial diagnostic tool for identifying this condition. Here are some key ECG changes that suggest myocardial ischemia:


1. ST-segment depression: This is one of the most common signs of ischemia. It occurs when the ST segment is depressed more than 1 mm below the baseline in leads facing the affected area of the heart.


2. T-wave inversion: Deep, symmetrical T-wave inversions, particularly in leads that correspond to the ischemic region, can be indicative of ischemia.


3. ST-segment elevation: While this is more commonly associated with myocardial infarction (heart attack), it can also be seen in severe ischemia.


4. Q-wave abnormalities: The presence of new or presumably new Q waves (particularly if they are deeply inverted) can suggest a prior or current ischemic event.


5. Arrhythmias: Various types of arrhythmias, such as atrial or ventricular premature beats, atrial fibrillation, or even ventricular tachycardia, can be associated with ischemia.


6. Prolonged QT interval: This can be a sign of electrolyte imbalances that may accompany ischemia.

7.
Nonspecific ST-T wave changes: These can be indicative of ischemia, particularly when they are dynamic and change over time.

It's important to note that ECG changes can be subtle and may not always be present, especially in the early stages of ischemia. Additionally, ECG changes can be influenced by factors such as patient position, lead placement, and the presence of other medical conditions. Therefore, a comprehensive clinical assessment is necessary to interpret ECG findings accurately.

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The ECG sign of subendocardial ischemia is ST segment depression (A). Depression is reversible if ischemia is only transient but depression persists if ischemia is severe enough to produce infarction. T wave inversion with or without ST segment depression (B) is sometimes seen but not ST segment elevation or Q wave.read more >>