title: Troponin I levels in permanent atrial fibrillation-impact of rate control and exercise testing.
abstract: BACKGROUND
  High-sensitivity troponin I (hs-TnI) and troponin T (hs-TnT) are moderately correlated and independently related to outcome in atrial fibrillation (AF). Rate controlling therapy has been shown to reduce hs-TnT, however the potential impact on hs-TnI levels, and whether this differs from the effects on hs-TnT, has not been investigated previously.
  
  
  METHODS
  Sixty patients with stable, permanent AF without heart failure or known ischemic heart disease were included in a randomised crossover study (mean age 71 ± 9 years, 18 women). Diltiazem 360 mg, verapamil 240 mg, metoprolol 100 mg, and carvedilol 25 mg were administered once daily for three weeks, in a randomised sequence. At baseline and on the last day of each treatment period, hs-TnI was measured at rest and after a maximal exercise test and compared to hs-TnT.
  
  
  RESULTS
  Hs-TnI and hs-TnT correlated moderately at baseline (rs = 0.582, p < 0.001). All drugs reduced both the resting and the peak exercise levels of hs-TnI compared with baseline (p < 0.001 for all). The decline in resting hs-TnI and hs-TnT values relative to baseline levels was similar for all drugs except for verapamil, which reduced hs-TnI more than hs-TnT (p = 0.017). Levels of hs-TnI increased significantly in response to exercise testing at baseline and at all treatment regimens (p < 0.001 for all). The relative exercise-induced increase in hs-TnI was significantly larger compared to hs-TnT at baseline (p < 0.001), on diltiazem (p < 0.001) and on verapamil (p = 0.001).
  
  
  CONCLUSIONS
  In our population of stable, permanent AF patients, all four rate control drug regimens reduced hs-TnI significantly, both at rest and during exercise. The decline in hs-TnI and hs-TnT levels associated with beta-blocker and calcium channel blocker treatment was similar, except for a larger relative decrease in hs-TnI levels following verapamil treatment.
  
  
  BACKGROUND
  www.clinicaltrials.gov ( NCT00313157 ).
authors.affiliation: Department of Medical Research, Baerum Hospital, Vestre Viken Hospital Trust, N-3004, Drammen, Norway. awhorjen@gmail.com.|Faculty of Medicine, University of Oslo, Oslo, Norway. awhorjen@gmail.com.
authors.forename: Anja Wiedswang
authors.initials: AW
authors.lastname: Horjen
authors.affiliation: Department of Medical Research, Baerum Hospital, Vestre Viken Hospital Trust, N-3004, Drammen, Norway.
authors.forename: Sara Reinvik
authors.initials: SR
authors.lastname: Ulimoen
authors.affiliation: Department of Medical Research, Baerum Hospital, Vestre Viken Hospital Trust, N-3004, Drammen, Norway.
authors.forename: Steve
authors.initials: S
authors.lastname: Enger
authors.affiliation: Clinic for Medical Diagnostics, Vestre Viken Hospital Trust, Drammen, Norway.
authors.forename: Jon
authors.initials: J
authors.lastname: Norseth
authors.affiliation: Faculty of Medicine, University of Oslo, Oslo, Norway.|Center for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.
authors.forename: Ingebjørg
authors.initials: I
authors.lastname: Seljeflot
authors.affiliation: Faculty of Medicine, University of Oslo, Oslo, Norway.|Center for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.
authors.forename: Harald
authors.initials: H
authors.lastname: Arnesen
authors.affiliation: Department of Medical Research, Baerum Hospital, Vestre Viken Hospital Trust, N-3004, Drammen, Norway.
authors.forename: Arnljot
authors.initials: A
authors.lastname: Tveit
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D002227:Carbazoles / Q000627:therapeutic use; D000077261:Carvedilol; D018592:Cross-Over Studies; D004110:Diltiazem / Q000627:therapeutic use; D015536:Down-Regulation; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use; D008875:Middle Aged; D009664:Norway; D011237:Predictive Value of Tests; D011412:Propanolamines / Q000627:therapeutic use; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood; D014700:Verapamil / Q000627:therapeutic use
chemical_list: D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D015415:Biomarkers; D002121:Calcium Channel Blockers; D002227:Carbazoles; D011412:Propanolamines; D019210:Troponin I; D020107:Troponin T; D000077261:Carvedilol; D014700:Verapamil; D004110:Diltiazem; D008790:Metoprolol
keywords: Atrial fibrillation; Biomarkers; Exercise testing; High-sensitivity cardiac troponin I; High-sensitivity cardiac troponin T; Rate control