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Heart doi:10.1136/heartjnl-2012-303202
  • Education in Heart
  • Systemic disorders in heart disease

Analytically false or true positive elevations of high sensitivity cardiac troponin: a systematic approach

  1. Evangelos Giannitsis1
  1. 1Department of Internal Medicine III, Cardiology, University Hospital Heidelberg, Heidelberg, Germany
  2. 2Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
  3. 3Central Laboratory, University Hospital Heidelberg, Heidelberg, Germany
  4. 4Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany
  1. Correspondence to Professor Evangelos Giannitsis, Department of Internal Medicine III, Cardiology, University Hospital Heidelberg, Medizinische Klinik III, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; evangelos_giannitsis{at}med.uni-heidelberg.de

Cardiac troponin (cTn) is a regulatory protein of the myofibrillar thin filament of striated muscle regulating excitation–contraction coupling in the heart.w1 Among the three subunits (T, I, and C), only cardiac troponin T (cTnT) and I (cTnI) are expressed in cardiac muscle and released into blood following myocardial cell death. Several distinct pathobiological mechanisms leading to elevated troponin values have been suggested, not all of which involve myocyte necrosis.w2

cTnT or cTnI are routinely used in emergency units as the preferred biomarkers for the diagnosis of acute myocardial infarction (MI). According to joint criteria for the diagnosis of acute MI by the European Society of Cardiology/American College of Cardiology/American Heart Association/World Heart Federation Task Force, an acute MI should be diagnosed in patients with symptoms of myocardial ischaemia and detection of a rise and/or fall of cardiac biomarkers (preferentially troponins) with at least one value above the 99th percentile of the upper reference limit.1

Use of high sensitivity troponin assays allows more accurate and earlier detection of MI.2 w3 Higher analytical sensitivity increases the number of patients with analytically true positive cTn results due to non-ST elevation MI (NSTEMI) but also due to numerous acute or chronic diseases in the absence of overt ischaemic heart disease (box 1).3 w4

Box 1

Elevations of cardiac troponin values because of myocardial injury

Injury related to primary myocardial ischaemia

  • Plaque rupture

  • Intraluminal coronary artery thrombus formation

Injury related to supply/demand imbalance of myocardial ischaemia

  • Tachy-/bradyarrhythmias

  • Aortic dissection or severe aortic valve disease

  • Hypertrophic cardiomyopathy

  • Cardiogenic, hypovolaemic, or septic shock

  • Severe respiratory failure

  • Severe anaemia

  • Hypertension with or without left ventricular hypertrophy

  • Coronary spasm

  • Coronary embolism or vasculitis

  • Coronary endothelial dysfunction without significant coronary artery disease

Injury not related to myocardial ischaemia

  • Cardiac contusion, surgery, ablation, pacing, or …