title: Short-term amiodarone treatment for atrial fibrillation after catheter ablation induces a transient thyroid dysfunction: Results from the placebo-controlled, randomized AMIO-CAT trial.
abstract: BACKGROUND
  Amiodarone is known to affect the thyroid, but little is known about thyroid recovery after short-term amiodarone treatment.
  
  
  OBJECTIVE
  We aimed to evaluate the impact of 8weeks of amiodarone treatment on thyroid function in patients with atrial fibrillation (AF) undergoing catheter ablation in a randomised, double-blind clinical trial.
  
  
  METHODS
  212 patients referred for AF ablation at two centres were randomized to 8weeks of oral amiodarone or placebo. Thyroid function tests (TSH, thyroid stimulating hormone; T4, thyroxine; T3, triiodothyronine; fT4, free T4; fT3, free T3) were performed at baseline and 1, 3 and 6months.
  
  
  RESULTS
  Study drug was discontinued due to mild thyroid dysfunction in 1 patient in the placebo vs. 3 in the amiodarone group (p=0.6). In linear mixed models there were significant effects of amiodarone on thyroid function tests, modified by follow-up visit (p<10(-9) for both TSH, T4, T3, fT4 and fT3). The amiodarone group had higher TSH, fT4 and T4 after 1 and 3months compared to placebo, whereas T3 and fT3 were lower. In all cases, the amiodarone-induced thyroid dysfunction was largest at 1month, declining at 3months, and with no differences at 6months, compared to baseline.
  
  
  CONCLUSIONS
  We found amiodarone to have a significant impact on thyroid function after only 1month, but with a fast recovery of thyroid function after amiodarone discontinuation. Our study indicates that short-term amiodarone can be considered safe in patients without prior thyroid dysfunction.
authors.affiliation: Department of Cardiology, Section 2013, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark. Electronic address: Soeren.Zoega.Diederichsen@regionh.dk.
authors.forename: Søren Zöga
authors.initials: SZ
authors.lastname: Diederichsen
authors.affiliation: Department of Cardiology, Section 2013, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Stine
authors.initials: S
authors.lastname: Darkner
authors.affiliation: Department of Cardiology, Section 2013, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Cardiology, Gentofte Hospital, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Arne
authors.initials: A
authors.lastname: Johannesen
authors.affiliation: Department of Cardiology, Section 2013, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Steen
authors.initials: S
authors.lastname: Pehrson
authors.affiliation: Department of Cardiology, Gentofte Hospital, Copenhagen University Hospital, Gentofte, Denmark.
authors.forename: Jim
authors.initials: J
authors.lastname: Hansen
authors.affiliation: Department of Medical Endocrinology, Section 2132, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Ulla
authors.initials: U
authors.lastname: Feldt-Rasmussen
authors.affiliation: Department of Cardiology, Section 2013, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; The Danish National Research Centre for Cardiac Arrhythmia, Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jesper Hastrup
authors.initials: JH
authors.lastname: Svendsen
mesh_terms: D000368:Aged; D000638:Amiodarone / Q000009:adverse effects* / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000628:therapy*; D017115:Catheter Ablation; D003718:Denmark; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D013959:Thyroid Diseases / Q000139:chemically induced*; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects*; D013963:Thyroid Hormones / Q000097:blood*
chemical_list: D000889:Anti-Arrhythmia Agents; D013963:Thyroid Hormones; D000638:Amiodarone
keywords: Amiodarone; Atrial fibrillation; Randomized controlled trial; Thyroid function tests