Thyroid Hormone Predisposes Rabbits to Atrial Arrhythmias by Shortening Monophasic Action Period and Effective Refractory Period: Results from an in Vivo Study

Overview

Journal J Endocrinol Invest

Publisher Springer

Specialty Endocrinology

Date 2009 Jun 23

PMID 19542744

Citations 1

Authors

Z Yu

C-X Huang

S-Y Wang

T Wang

L Xu

Affiliations

Soon will be listed here.

Abstract

Background: Atrial arrhythmias are common complications of hyperthyroidism, but the underlying mechanisms remain to be further clarified. Thus, in this study, we try to investigate the effects of thyroid hormone on atrial electrophysiology by using a hyperthyroidism model in vivo.

Materials And Methods: Twenty-four New Zealand white rabbits were randomized into Thyroxine group (no.=12) and Control group (no.=12). In Thyroxine group, Levo-thyroxine (L-T(4)) solution (1 mg/kg x d(-1)) was injected daily into the peritoneum for 2 weeks. In Control group, the same amount of saline was injected. On day 15, 8 rabbits in each group were chosen randomly to receive electrophysiological experiment in vivo, in which electrophysiological parameters and atrial arrhythmias induced by electrical stimulation were recorded and serum thyroid hormone levels were examined. The others were killed so as to exam the L-type calcium current of atrium.

Results: Atrial monophasic action potential at 90 repolarization (AMAP(90)) and effective refractory period (AERP) were significantly shorter in Thyroxine group than in Control group (AMAP(90): 103.21+/-1.94 vs 122.14+/-6.13, p<0.01; AERP: 82.69+/-0.99 vs 102.46+/-2.32, p<0.01). There are significant differences in the incidence of atrial arrhythmias between the two groups. The mean peak of L-type calcium current (I(Ca,L)) densities (pA/pF) at -10mV was significantly higher in Thyroxine group than in Control group (-8.59+/-0.68 vs -6.54+/-0.49, no.=8, p<0.001).

Conclusions: In our hyperthyroidism model, thyroid hormone predisposed rabbits to atrial arrhythmias by shortening AMAP and AERP, which might be associated with increased I(Ca,L) current densities in atrium.

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References

Gammage M, Parle J, Holder R, Roberts L, Hobbs F, Wilson S . Association between serum free thyroxine concentration and atrial fibrillation. Arch Intern Med. 2007; 167(9):928-34. DOI: 10.1001/archinte.167.9.928. View

Washizuka T, Horie M, Watanuki M, Sasayama S . Endothelin-1 inhibits the slow component of cardiac delayed rectifier K+ currents via a pertussis toxin-sensitive mechanism. Circ Res. 1997; 81(2):211-8. DOI: 10.1161/01.res.81.2.211. View

Watanabe H, Ma M, Washizuka T, Komura S, Yoshida T, Hosaka Y . Thyroid hormone regulates mRNA expression and currents of ion channels in rat atrium. Biochem Biophys Res Commun. 2003; 308(3):439-44. DOI: 10.1016/s0006-291x(03)01420-7. View

Sun Z, Ojamaa K, Nakamura T, ARTMAN M, Klein I, Coetzee W . Thyroid hormone increases pacemaker activity in rat neonatal atrial myocytes. J Mol Cell Cardiol. 2001; 33(4):811-24. DOI: 10.1006/jmcc.2001.1353. View

Parmar M . Thyrotoxic atrial fibrillation. MedGenMed. 2005; 7(1):74. PMC: 1681414. View

Disatnik M, Shainberg A . Regulation of beta-adrenoceptors by thyroid hormone and amiodarone in rat myocardiac cells in culture. Biochem Pharmacol. 1991; 41(6-7):1039-44. DOI: 10.1016/0006-2952(91)90212-n. View

Pantos C, Malliopoulou V, Paizis I, Moraitis P, Mourouzis I, Tzeis S . Thyroid hormone and cardioprotection: study of p38 MAPK and JNKs during ischaemia and at reperfusion in isolated rat heart. Mol Cell Biochem. 2003; 242(1-2):173-80. View

Ponchon P, Laude D, Elghozi J . Contribution of the autonomic nervous system to blood pressure and heart rate variability changes in early experimental hyperthyroidism. Eur J Pharmacol. 1998; 352(2-3):247-55. DOI: 10.1016/s0014-2999(98)00368-9. View

Davis P, DAVIS F . Acute cellular actions of thyroid hormone and myocardial function. Ann Thorac Surg. 1993; 56(1 Suppl):S16-23. DOI: 10.1016/0003-4975(93)90550-2. View

10.

Sunagawa M, Yamakawa M, Shimabukuro M, Higa N, Takasu N, Kosugi T . Electrophysiologic characteristics of atrial myocytes in levo-thyroxine-treated rats. Thyroid. 2005; 15(1):3-11. DOI: 10.1089/thy.2005.15.3. View

11.

Li X, Huang C, Jiang H, Cao F, Wang T . The beta-adrenergic blocker carvedilol restores L-type calcium current in a myocardial infarction model of rabbit. Chin Med J (Engl). 2005; 118(5):377-82. View

12.

Hoit B, Khoury S, Shao Y, Gabel M, Liggett S, Walsh R . Effects of thyroid hormone on cardiac beta-adrenergic responsiveness in conscious baboons. Circulation. 1997; 96(2):592-8. DOI: 10.1161/01.cir.96.2.592. View

13.

Bosch R, Nattel S . Cellular electrophysiology of atrial fibrillation. Cardiovasc Res. 2002; 54(2):259-69. DOI: 10.1016/s0008-6363(01)00529-6. View

14.

Johnson P, FREEDBERG A, Marshall J . Action of thyroid hormone on the transmembrane potentials from sinoatrial node cells and atrial muscle cells in isolated atria of rabbits. Cardiology. 1973; 58(5):273-89. DOI: 10.1159/000169643. View

15.

Dinanian S, Boixel C, Juin C, Hulot J, Coulombe A, Rucker-Martin C . Downregulation of the calcium current in human right atrial myocytes from patients in sinus rhythm but with a high risk of atrial fibrillation. Eur Heart J. 2008; 29(9):1190-7. DOI: 10.1093/eurheartj/ehn140. View

16.

Cappola A, Fried L, Arnold A, Danese M, Kuller L, Burke G . Thyroid status, cardiovascular risk, and mortality in older adults. JAMA. 2006; 295(9):1033-41. PMC: 1387822. DOI: 10.1001/jama.295.9.1033. View

17.

Binah O, Rubinstein I, Gilat E . Effects of thyroid hormone on the action potential and membrane currents of guinea pig ventricular myocytes. Pflugers Arch. 1987; 409(1-2):214-6. DOI: 10.1007/BF00584774. View

18.

Klein I, LEVEY G . New perspectives on thyroid hormone, catecholamines, and the heart. Am J Med. 1984; 76(2):167-72. DOI: 10.1016/0002-9343(84)90768-x. View

19.

Kahaly G, Dillmann W . Thyroid hormone action in the heart. Endocr Rev. 2005; 26(5):704-28. DOI: 10.1210/er.2003-0033. View

20.

Meo S, de Martino Rosaroll P, Piro M, DE LEO T . Electrophysiological properties of the hyperthyroid rat heart. Arch Int Physiol Biochim Biophys. 1994; 102(2):153-9. DOI: 10.3109/13813459408996124. View