Can an ECG exam detect if you HAD an infarction in the past?
ECG may or may not show an old infarction. Myocardial infarctions can be Q wave or non Q wave infarctions. If it is a Q wave infarction it usually persists in ECG even after recovery. So future ECGs will show it. In non Q wave infarctions the ECGs may be normal after recovery or with minor changes only. So we cannot say for sure about past infarctions in these cases. Q wave infarctions are more serious than non Q wave infarctions usually. Even when the patient himself may not have experienced a heart attack, sometimes ECG may show evidence of old infarction in the form of Q waves. In those cases the patient may have had a silent Myocardial infarction and never knew it at that time.
