title: Radioiodine ablation of the thyroid to prevent recurrence of amiodarone-induced thyrotoxicosis in patients with resistant tachyarrhythmias.
abstract: Amiodarone-induced thyrotoxicosis (AIT) is a common complication of amiodarone therapy. Although permanent withdrawal of amiodarone is recommended due notably to the risk of worsening of tachyarrhythmias, some patients may require the reintroduction of amiodarone several months after normalizing their thyroid function. We, retrospectively, assessed the effects of (131)I therapy to prevent recurrence of AIT in euthyroid patients requiring reintroduction of amiodarone.
  
  
  METHODS
  Amiodarone was required in 10 cases of recurrent symptomatic paroxysmal atrial fibrillation (AF) and in 5 cases of ventricular tachycardia (VT) (M = 12, F = 3, mean age: 63 +/- 14). The underlying heart disease was dilated cardiomyopathy (n = 4), ischaemic heart disease (n = 4), hypertensive heart disease (n = 2), arrhythmogenic right ventricular dysplasia (n = 27) and valvulopathy (n = 1). Two patients had idiopathic paroxysmal AF.
  
  
  RESULTS
  A mean (131)I dose of 579 +/- 183 MBq was administered 34 +/- 37 after the episode of AIT. Amiodarone was reintroduced in 14 of 15 patients after a mean interval of 103 +/- 261 d. Fourteen patients developed definite hypothyroidism necessitating l-thyroxine but we observed no late recurrence of AIT. After a mean follow-up of 22 +/- 16 months, tachyarrhythmias were controlled in 12 of 14 patients.
  
  
  CONCLUSIONS
  (131)I therapy appears to be an effective and safe approach to prevent the recurrence of AIT in a patient requiring the reintroduction of amiodarone for tachyarrhythmias.
authors.affiliation: Cardiology Department, Hôpital Sud, Centre Hospitalier Universitaire, University Hospital, 80054 Amiens Cedex, France.
authors.forename: Jean-Sylvain
authors.initials: JS
authors.lastname: Hermida
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Tcheng
authors.forename: Genevieve
authors.initials: G
authors.lastname: Jarry
authors.forename: Veronique
authors.initials: V
authors.lastname: Moullart
authors.forename: Sylvie
authors.initials: S
authors.lastname: Arlot
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Rey
authors.forename: Jean
authors.initials: J
authors.lastname: Delonca
authors.forename: Claire
authors.initials: C
authors.lastname: Schvartz
mesh_terms: D000638:Amiodarone / Q000009:adverse effects* / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects* / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012306:Risk; D017180:Tachycardia, Ventricular / Q000188:drug therapy*; D013961:Thyroid Gland / Q000528:radiation effects*; D013971:Thyrotoxicosis / Q000139:chemically induced* / Q000517:prevention & control*
chemical_list: D000889:Anti-Arrhythmia Agents; D007457:Iodine Radioisotopes; D000638:Amiodarone