Myoglobin is an enzyme released during skeletal or cardiac muscle injury. The protein is also released when hemoglobin leaks from damaged red blood cells. Although it may be used to help determine myocardial damage, myoglobin is not specific to cardiac injury. Increased myoglobin levels indicate early myocardial injury but lacks specificity for diagnosing, since it is not specific to cardiac injury.
The onset of elevated myoglobin levels is within 1-4 hours. Since myoglobin is released into the bloodstream approximately one hour after myocardial injury, it is the earliest indicator of myocardial injury.
The peak of increased myoglobin levels is within 12 hours.
After myocardial damage, myoglobin levels return to baseline within 24 hours. The only way to diagnose myocardial reinfarction is a determining increased myoglobin levels after 24 hours of initial symptoms.
After 24 hours of initial symptoms, the patient's myoglobin levels should return to normal. If the levels remain elevated after 24 hours, the patient may be experiencing myocardial reinfarction.
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