Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation. (December 2018)

• Record Type: Journal Article
• Authors: dos Santos, Luis; Antonio, Ednei L.; Serra, Andrey J.; Yoshizaki, Amanda; Seibt, Larissa; Silva, Flavio A.; Couto, Gisele K.; Rossoni, Luciana V.; Tucci, Paulo; de Paola, Angelo A.; Fenelon, Guilherme
• Is Part Of: IJC heart & vasculature. Volume 21(2018)
• Page Start: 22
• Page End: 28
• Publication Date: 2018-12
• Subjects: Radiofrequency ablation -- Atrial fibrosis -- Heart failure -- Atrial fibrillation; Cardiovascular system -- Diseases -- Periodicals; Cardiovascular system -- Pathophysiology -- Periodicals; 616.1005
• DOI: 10.1016/j.ijcha.2018.09.003
• Languages: English
• ISSNs: 2352-9067

Abstract

Abstract: Background: Atrial fibrillation (AF) frequently coexists with congestive heart failure (CHF). The increased susceptibility to AF in CHF has been attributed to a variety of structural and electrophysiological changes in the atria, particularly dilation and interstitial fibrosis. We evaluated atrial remodeling and AF vulnerability in a rat model of CHF induced by left ventricle (LV) radiofrequency (RF) ablation. Methods: Wistar rats were divided into 3 groups: RF-induced CHF (Ab, n = 36), CHF animals treated with spironolactone (AbSpi, n = 20) and sham controls (Sham, n = 29). After 12 weeks, animals underwent echocardiographic and electrophysiological evaluation and were sacrificed for histological (atrial fibrosis) and Western blotting (TGF-β1, collagen I/III, connexin 43 and CaV 1.2) analysis. Results: Mild LV dysfunction and marked atrial enlargement were noted in both ablated groups. AF inducibility (episodes ≥2 s) increased in the Ab group compared to sham animals (31/36, 86%; vs. 15/29, 52%; p = 0.005), but did not differ from the AbSpi group (16/20, 80%; p = NS). Sustained AF (>30 s) was also more frequent in the Ab group compared to shams (56% vs. 28%; p = 0.04). Spironolactone reduced atrial fibrosis (p < 0.01) as well as TGF-β1 (p < 0.01) and collagen I/III (p < 0.01) expression but did not affect connexin 43 and CaV 1.2 expression. Conclusions: Rats with RF-induced CHF exhibit pronounced atrial structural remodeling and enhanced AF vulnerability. This model may be useful for studying AF substrate in CHF. Highlights: A novel rat model of heart failure induced by left ventricle RF ablation. Marked atrial structural changes (dilation and interstitial fibrosis). Increased expression of TGF-β1 and collagen I/III and decreased Connexin 43 and CaV 1.2 Enhanced atrial fibrillation (AF) vulnerability compared to sham controls Spironolactone reduced atrial fibrosis and TGF-β1 and collagen I/III expression.