Why do some patients with myocardial infarction have high markers of myocardial injury, but their electrocardiogram is normal?

1. How do you know about myocardial infarction? Second, which marker of myocardial injury are you talking about?

Because myocardial infarction can lead to myocardial injury, which leads to the increase of myocardial injury markers, but it can also cause myocarditis. Your ECG is not showing, so how do you know myocardial infarction?

Also, if the marker of myocardial injury is troponin (troponin T or troponin I), then the myocardial specificity is very high, so most of it is myocardial injury, and minor myocardial injury can also be reflected. For example, sometimes ST segment depression of ECG is actually higher than the original, but it is only offset by the original. Then it looks normal. Moreover, the later T wave has not been fully reflected in time.

It is also possible that the location of your myocardial infarction is special and there is no full lead. Usually, we require that the routine electrocardiogram should have 12 leads. If the right chest leads V3R, V4R, V5R and the back wall leads V7, V8, V9 are added to the myocardial infarction, some primary hospitals only have 9 leads, so it is possible to miss the diagnosis of smaller myocardial infarction or myocardial infarction in special parts.

Also, if you are not making troponin with very high specificity, but creatine phosphokinase CK and its isoenzyme CK-MB, then CK itself can be in myocardium, skeletal muscle and brain tissue. If you have a skeletal muscle injury, even CK-MB is more in the myocardium than in the skeletal muscle, but if you have a large number of skeletal muscle injuries, CK-MB can also increase a lot, so it is a big joke to say myocardial infarction alone.