Improved rate control reduces cardiac troponin T levels in permanent atrial fibrillation.
BACKGROUND
Detectable levels of troponins are often found in serum of patients with atrial fibrillation (AF), and recent reports suggest that Tn concentrations are independently related to patient prognosis.


OBJECTIVE
We hypothesized that treatment with common rate-reducing drugs might lower the levels of cardiac troponin T (TnT) in patients with permanent AF. We also wanted to investigate whether the different drugs would impact the Tn levels differently.


METHODS
Sixty patients were included (mean age 71 ± 9 years, 18 women) in this randomized crossover study. All patients had stable, permanent AF without ischemic heart disease or congestive heart failure. Diltiazem 360 mg, verapamil 240 mg, metoprolol 100 mg, and carvedilol 25 mg were administered once daily for 3 weeks, in a randomized sequence. At baseline and on the last day of each treatment period, TnT concentrations were measured at rest and after a maximal exercise test.


RESULTS
TnT was detectable in all patients. In 22% of the patients, TnT concentrations were above the threshold normally used for diagnosing myocardial infarction. All drugs reduced the levels of TnT significantly compared with baseline (P < 0.001 for all), but there were no significant differences between the treatments. Levels of TnT increased significantly in response to exercise testing (P < 0.001 for all).


CONCLUSIONS
Elevated TnT was demonstrated in a large proportion of stable patients with permanent AF without ischemic heart disease. A moderate reduction of heart rate by the study drugs was associated with a significant reduction in levels of TnT.
Department of Medical Research, Vestre Viken Hospital Trust, Baerum Hospital, Rud, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway.
Sara R
SR
Ulimoen
Steve
S
Enger
Jon
J
Norseth
Are H
AH
Pripp
Michael
M
Abdelnoor
Harald
H
Arnesen
Knut
K
Gjesdal
Arnljot
A
Tveit
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; D002227:Carbazoles / Q000627:therapeutic use; D000077261:Carvedilol; D018592:Cross-Over Studies; D004110:Diltiazem / Q000627:therapeutic use; D015536:Down-Regulation; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use; D008875:Middle Aged; D009664:Norway; D011412:Propanolamines / Q000627:therapeutic use; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D020107:Troponin T / Q000097:blood*; D014700:Verapamil / Q000627:therapeutic use
D000889:Anti-Arrhythmia Agents; D015415:Biomarkers; D002227:Carbazoles; D011412:Propanolamines; D020107:Troponin T; D000077261:Carvedilol; D014700:Verapamil; D004110:Diltiazem; D008790:Metoprolol