Simple Cardiac Ischemia - ECG
The simple ischemia of the heart muscle (meaning ischemia with exception of the STEMI infarction) is typically associated with changes in the ST segment and T wave that are usually found in leads perpendicular to the plane of ischemia (e.g. leads II, III, aVF for the inferior wall). The classic changes include ST segment depression and T wave negativity. It is necessary to take into account that these changes should be present in more than one lead. In addition, we must remember that the above ECG changes can be part of some bundle branch blocks (LBBB, RBBB, etc).
The ECG finding must be evaluated together with patient’s symptoms and cardiac enzymes serum levels. Without any symptom, the ECG may show a “silent” ischemia. Positive ECG finding with a chest pain and negative cardiac enzymes is typical for a bout of angina pectoris while positive ECG, positive cardiac enzymes and chest pain show the non-STEMI infarction.
There are ST and T changes in leads II, III, aVF (solid red circles) – it is a suspicion of ischemia of the inferior myocardial wall. Similar change is outlined in the lead V6 (dashed circle).
Conclusion: Incidental finding of ischemic changes should be followed by a cautious medical history, physical examination and echocardiography. When a heart ischemia is suspicious, we can choose between conservative (pharmacotherapy) and invasive approach (coronary angiography). In a patient with unstable angina pectoris or even non-STEMI we usually proceed invasively by indicating the coronary angiography.