<prompt> False regarding levels of cardiac biomarkers following ischemic injury to the heartTroponin peaks earlier than CK-MBTroponin returns to normal in three daysCK-MB is less sensitive than troponinCK-MB returns to normal in 48-72 hours  <response>: Answer: b Troponin returns to normal in three days HARRISON 19TH ED, P-1600SERUM 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 CKbut 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 ngmLMyoglobin is released more rapidly within 2 hrs from infracted myocardium; useful for detection of early reinfarctionB-type Natriuretic peptideBNP 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 stylefont-size: 1.04761904761905em; font-family: Times New Roman, Times, serif 