title: Permanent atrial fibrillation in heart failure patients as another condition with increased reverse triiodothyronine concentration.
abstract: OBJECTIVE
  To fully investigate the thyroid hormonal function in patients with the most common arrhythmia - atrial fibrillation.
  
  
  METHODS
  120 patients (aged 55-85 yrs) with symptoms of congestive heart failure exacerbation and no other concomitant disorders (inclusion criteria: normal cardiac troponin T at admission and 12 hours after, normal renal, hepatic and respiratory function; exclusion criteria: inflammatory state, history of myocardial infarction). Depending on the presence of permanent atrial fibrillation (PAF), patients were divided into two groups: PAF (34 females, 26 males) and regular sinus heart rhythm (43 females, 17 males), the groups did not differ in terms of heart rate, blood pressure, presence of overt/subclinical thyroid dysfunction, and medical therapy used. In all subjects thyroid stimulating hormone, free thyroxine, free triiodothyronine, reverse triiodothyronine were measured; echocardiography was performed.
  
  
  RESULTS
  PAF group showed higher FT4 and rT3 (1.41 vs. 1.27 ng/dl, p=0.0007; 0.61 vs. 0.32 ng/ml, p<0.0001, respectively). With ROC curve analysis the biochemical thyroid related factor of the highest prognostic value for PAF occurrence (with the highest sensitivity and specificity: 77% and 72%, respectively) was rT3 with the cut-off of above 0.3 ng/ml. Also, a positive correlation between rT3 levels and left ventricular posterior wall diameter was observed (Spearman's correlation coefficient 0.33, p=0.0093).
  
  
  CONCLUSIONS
  PAF is another condition where an increase in rT3 is observed. rT3 concentration above 0.3 ng/ml may be a novel biochemical sign associated with the presence of PAF in patients with chronic heart failure.
authors.affiliation: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Jakowczuk
authors.affiliation: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Dominika
authors.initials: D
authors.lastname: Zalas
authors.affiliation: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Owecki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000097:blood* / Q000150:complications; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000150:complications; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood* / Q000150:complications; D007037:Hypothyroidism / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D013974:Thyroxine