| Objectives: To investigate the alterations of potassium and calcium ion channel as well as NCX gene expressions in right atria of patients with sinus rhyth and heart failure(HF). To find out the effects of HF on atrial ion channel electrophysiology in patients with sinus rhythm. To discuss the role of HF-induced atrial ionic channel remodeling in the associated substrate of atrial fibrillation(AF). To discuss the potential mechanisms of atrial fibrillation in heart failure.Methods: Right atrial appendages were obtained from 18 patients with heart failure and 18 matched controls with normal cardic function. All patients were in sinus rhythm. The mRNA expressions of Ito1(Kv4.3 α ), Iks(KvLQT1), Ikur (Kv1.5), L-type Ca2+ channel (L-Ca α1c) and NCX were measured by reverse transcription-polymerase chain reaction and normalized to the mRNA level of glyceraldehydes-3 -phosphate dehydrogenase.Results: Compared to those in the control, mRNA expression of Ito1(Kv4.3 α ) (0.83±0.07 vs 0.45±0.09, P<0.01) , Iks(KvLQT1) (0.56 ± 0.04 vs 0.36 ± 0.06, P<0.01), and L-type Ca2+channel (L-Ca α1c) (0.42 + 0.09 Vs 0.25 + 0.06, P<0.01) reduced by 46.20%,36.32% and 41.66%, respectively, in patients with HF. The mRNAexpression of Ikur (Kvl.5) were not altered (0.34 + 0.07 vs 0.30±0.05,P>0.05) ,and the mRNA levels of NCX increased by 64.68% (0.19 + 0.05 vs 0.31 +0.07, PO.01) in HF patients campared with the control. Conclusions:1. The mRNA levels of I,oi(Kv4.3 a ), Iks(KvLQTl), L-type Ca2+channel (L-Ca a lc) were down-regulated but the mRNA level of NCX was up-regulated, while The mRNA level of Ikur (Kvl.5) was not altered in patients with HF. The alterations of gene expressions might be the molecular basis of the altered atrial cellular ion currents in patients with HF.2. HF-induced atrial ionic remodeling might play an important role in the associated AF substrate and contribute to the potential mechanisms of atrial fibrillation in HF.
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