Which enzyme rises earliest in the blood following a myocardial infarction?

The enzyme that rises earliest in the blood following a myocardial infarction is actually Troponin, making it a critical biomarker for diagnosing heart attacks. Troponin levels begin to rise within 3 to 6 hours and can remain elevated for days, which helps in the assessment of myocardial injury.

While CPK (Creatine Phosphokinase) does increase after a myocardial infarction, it typically rises later than Troponin, within approximately 4 to 6 hours, peaking around 24 hours. This delayed response places Troponin as the more sensitive and specific marker for early detection of acute myocardial infarction, whereas CPK may reflect other muscle injuries as well.

Understanding the timing and specificity of these biomarkers is crucial for clinical decision-making and for guiding the management of patients suspected of having a heart attack.