Cardiac Medicine Certification (CMC) Practice Exam

What is the timeframe in which CK-MB levels are expected to peak after myocardial infarction?

1. 4-6 hours

2. 10-24 hours

3. 24-48 hours

4. 48-72 hours

The correct answer is: 10-24 hours

CK-MB, or creatine kinase myocardial band, is an enzyme that is crucial for diagnosing myocardial infarction (MI). After a heart attack, CK-MB levels typically begin to rise within 3 to 6 hours after the onset of chest pain. They reach peak levels generally between 10 to 24 hours after the ischemic event. This peak timing is significant because it allows healthcare professionals to interpret the results in conjunction with the timing of the patient's symptoms. Once the levels peak, they usually start to decline, returning to baseline levels within 48 to 72 hours. Understanding this timeframe is essential for accurate diagnosis and treatment planning. The timing also helps differentiate between a recent MI and earlier cardiac events, as other cardiac markers may have different peak times. Thus, the peak timeframe of 10 to 24 hours after myocardial infarction for CK-MB is critical information for clinicians monitoring patients with suspected cardiac events.