Document Detail

Thyroid hormone replacement therapy attenuates atrial remodeling and reduces atrial fibrillation inducibility in a rat myocardial infarction-heart failure model.
MedLine Citation:
PMID:  25305503     Owner:  NLM     Status:  In-Data-Review    
BACKGROUND: Heart failure (HF) is associated with increased atrial fibrillation (AF) risk. Accumulating evidence suggests the presence of myocardial tissue hypothyroidism in HF, which may contribute to HF development. In a recent report we demonstrated that hypothyroidism, like hyperthyroidism, leads to increased AF inducibility. The present study was designed to investigate the effect of thyroid hormone (TH) replacement therapy on AF arrhythmogenesis in HF.
METHODS AND RESULTS: Myocardial infarction (MI) was produced in rats by means of coronary artery ligation. Rats with large MIs (>40%) were randomized into L-thyroxine (T4; n = 14) and placebo (n = 15) groups 2 weeks after MI. Rats received 3.3 mg T4 (in 60-day release form) or placebo pellets for 2 months. Compared with the placebo, T4 treatment improved cardiac function and decreased left ventricular internal diameters as well as left atrial diameter. T4 treatment attenuated atrial effective refractory period prolongation (45 ± 1.5 ms in placebo group vs 37 ± 1.6 ms in T4 group; P < .01) and reduced AF inducibility (AF/atrial flutter/tachycardia were inducible in 11/15 rats [73%] in the placebo- vs 4/14 rats [29%] in the T4-treated group; P < .05). Arrhythmia reduction was associated with decreased atrial fibrosis but was not associated with connexin 43 changes.
CONCLUSIONS: To our knowledge this is the first study demonstrating that TH replacement therapy in HF attenuates atrial remodeling and reduces AF inducibility after MI-HF. Clinical studies are needed to confirm such benefits in human patients.
Youhua Zhang; Eduard I Dedkov; Bianca Lee; Ying Li; Khusbu Pun; A Martin Gerdes
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Publication Detail:
Type:  Journal Article     Date:  2014-11-25
Journal Detail:
Title:  Journal of cardiac failure     Volume:  20     ISSN:  1532-8414     ISO Abbreviation:  J. Card. Fail.     Publication Date:  2014 Dec 
Date Detail:
Created Date:  2014-12-01     Completed Date:  -     Revised Date:  2014-12-02    
Medline Journal Info:
Nlm Unique ID:  9442138     Medline TA:  J Card Fail     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1012-9     Citation Subset:  IM    
Copyright Information:
Copyright © 2014 Elsevier Inc. All rights reserved.
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