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Original research
Role of amiodarone in the management of atrial arrhythmias in adult Fontan patients
  1. Satoshi Kawada1,
  2. Praloy Chakraborty1,
  3. Lucy Roche2,
  4. Erwin N Oechslin2,
  5. Candice Silversides2,
  6. Rachel M Wald2,
  7. Eugene Downar1,
  8. Louise Harris1,
  9. Lorna Swan2,
  10. Rafael Alonso-Gonzalez2,
  11. Sara Thorne2,
  12. Kenichiro Yamamura2,
  13. Kumaraswamy Nanthakumar1,
  14. Blandine Mondésert3,
  15. Paul Khairy3,
  16. Krishnakumar Nair1
  1. 1Electrophysiology department, Division of Cardiology, University Health Network, Toronto General Hospital, Toronto, Ontario, Canada
  2. 2Toronto Congenital Cardiac Centre for Adults, Peter Munk Cardiac Centre, University of Toronto, Toronto General Hospital, Toronto, Ontario, Canada
  3. 3Electrophysiology Service and Adult Congenital Heart Disease, Department of Medicine, Montreal Heart Instiutue, Montreal, Quebec, Canada
  1. Correspondence to Dr Krishnakumar Nair, Electrophysiology Department, Division of Cardiology, University Health Network, Toronto General Hospital, Toronto, ON M5G 2C4, Canada; Krishnakumar.Nair{at}uhn.ca

Abstract

Background Patients with Fontan circulation are known to be at high risk for developing atrial tachyarrhythmias (AAs). Our objective was to examine the efficacy and safety of amiodarone in the management of ATs in adult Fontan patients.

Methods Primary outcomes of this single-centre, retrospective study included freedom from AAs and incidence of adverse effects of amiodarone on Fontan patients. Heart failure (HF) events and composite outcomes of death from any cause, Fontan revision and heart transplantation were evaluated as secondary outcomes. Predictors of HF and discontinuing amiodarone were also evaluated.

Results A total of 61 patients (mean age 31.6±11.3 years, 40.9% female), who were treated with amiodarone in between 1995 and 2018, were included. AAs free survival at 1, 3 and 5 years were 76.2%, 56.9% and 30.6%, respectively. During a median follow-up of 50.5 months, 34 (55.7%) patients developed side effects, and 20 (32.8%) patients discontinued amiodarone due to side effects. Thyroid dysfunction was the most common side effect (n=26, 76.5%), amiodarone-induced thyrotoxicosis (AIT) (n=16, 27.1%) being most common thyroid dysfunction. Young age (age <28.5 years) was associated with discontinuing amiodarone (HR 5.50, 95% CI 1.19 to 25.4, p=0.029). AIT significantly increased risk of HF (HR 4.82, 95% CI 1.71 to 13.6, p=0.003).

Conclusions Short-term efficacy of amiodarone in Fontan physiology is acceptable. However, long-term administration is associated with a reduction of efficacy and a significant prevalence of non-cardiac side effects. AIT is associated with exacerbation of HF. The judicious use of amiodarone administration should be considered in this population.

  • fontan physiology
  • atrial flutter
  • drug monitoring

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Footnotes

  • Contributors SK: conceived and designed the research, acquired data, performed statistical analysis and drafted the manuscript. PC: conceived and designed the research, drafted the manuscript and made critical revision of the manuscript. LR, EO, CKS, RW, ED, LH, LS, RA-G, ST, KY, KN, BM and PK: made critical revision for the manuscript for intellectual content. KN (corresponding author): conceived and designed the research, drafted the manuscript, made critical revision of the manuscript, handled supervision and responsible for the overall content as guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No data are available. The data, analytic methods and study materials underlying this article will not be shared with other researchers due to for the purpose of reproducing the results or replicating the procedure and the privacy of indivisuals that participated in the study.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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