title: Cardiac troponin I degradation in serum of patients with hypertrophic obstructive cardiomyopathy undergoing percutaneous septal ablation.
abstract: BACKGROUND
  Troponin has become the most important marker for diagnosing acute myocardial infarction, yet knowledge is scarce regarding appearance of specific degradation fragments in the blood. We have recently described the appearance of intact cardiac troponin I (cTnI) and 7 degradation products in patients suffering from ST-elevation myocardial infarction (STEMI) using Western blot analysis. However, the time resolution in STEMI patients is hampered by the rather vague time point 'onset of pain'. We therefore sought to utilize a time-wise more reliable model of human myocardial necrosis: percutaneous transluminal septal myocardial ablation (PTSMA) of hypertrophic obstructive cardiomyopathy (HOCM). Here the iatrogenic induction of myocardial necrosis occurs in vivo, allowing us to investigate degradation of cTnI by the second.
  
  
  METHODS
  Blood samples were obtained from 8 patients with HOCM just prior to initiation of PTSMA and up to 50 h following the procedure. Western blot analysis was performed with subsequent analysis of relative intensities of the bands as compared to the degradation of cTnI in STEMI patients from the ASSENT-2 troponin substudy.
  
  
  RESULTS
  We demonstrate intact cTnI and 9 degradation products [molecular weight (MW) 12.0-23.5 kDa]. The bands were comparable in MW to degradation fragments in STEMI. Their early rise in intensity, occurring within few minutes after the alcohol injection, emphasizes how susceptible troponin bands are to chemical/ischemic insults. Moreover, two additional bands were visible in the PTSMA population.
  
  
  CONCLUSIONS
  This work describes the degradation products of troponin I in HOCM patients undergoing PTSMA. The detected bands appear fast and are similar to degradations following STEMI. This model contributes to our knowledge of the degradation patterns of troponin in disease states, and may thus play a role in the interpretation of elevated troponin levels.
authors: Division of Cardiology, Aker University Hospital and Faculty of Medicine, University of Oslo, Oslo, Norway.
authors: Lene H
authors: LH
authors: Madsen
authors: Terje
authors: T
authors: Lund
authors: Zanina
authors: Z
authors: Grieg
authors: Ståle
authors: S
authors: Nygaard
authors: Lene
authors: L
authors: Holmvang
authors: Birgit
authors: B
authors: Jurlander
authors: Peer
authors: P
authors: Grande
authors: Geir
authors: G
authors: Christensen
authors: Dan
authors: D
authors: Atar
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000097:blood* / Q000601:surgery; D017115:Catheter Ablation; D005260:Female; D006346:Heart Septum / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D019210:Troponin I / Q000097:blood*
chemical_list: D019210:Troponin I