False regarding levels of cardiac biomarkers following ischemic injury to the heart
Answer: b) Troponin returns to normal in three days (HARRISON 19TH ED, P-1600)SERUM CARDIAC BIOMARKERSCKCardiac Troponins* CK-MB - most sensitive early marker (but overall less sensitive than troponin), but not specific* Starts to rise within 4-12 hrs, peaks at 24 hrs, falls to normal in 48-72 hrs* CK(but not CK-MB) also rises in i.m injection, exercise, skeletal muscle disease and trauma* CK-MB often rises after cardiac surgery, myocarditis, electrical cardioversion* Test of choice to diagnose re infarct* cTnT and cTnl - contractile proteins normally not present in serum* Most sensitive and specific markers of myocardial damage* cTnl - highly sensitive for damage to cardiac tissue* Rise within 2-6 hrs* peaks at 12-18 hours; normalizes at 5-10 days* The risk of death from an acute coronary syndrome is directly related to troponin level and patients with no detectable troponins have a good short-term prognosis* Minor troponin elevations seen in: CHF, myocarditis, pul. embolism* Elevated levels of CPK-MB and Troponins distinguish patients with NSTEMI from those with UA* 99th percentile cutoff point for troponin T (cTnT) is - 0.01 ng/mLMyoglobin is released more rapidly (within 2 hrs) from infracted myocardium; useful for detection of early reinfarctionB-type Natriuretic peptide(BNP) levels also rise after acute coronary syndromesMRI with gadolinium contrast enhancement - most sensitive to detect and quantitate extent of infarctionUp to 80% of patients with acute Ml will have an elevated troponin level within 2-3 hours of emergency department (ED) arrival, versus 6-9 hours or more with CK-MB and other cardiac markers ( style="font-size: 1.04761904761905em; font-family: Times New Roman, Times, serif">)
Troponin peaks earlier than CK-MB
Troponin returns to normal in three days
CK-MB is less sensitive than troponin
CK-MB returns to normal in 48-72 hours
C.V.S.