Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation.
Int J Cardiol Heart Vasc
; 21: 22-28, 2018 Dec.
Article
en En
| MEDLINE
| ID: mdl-30258978
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, nâ¯=â¯36), CHF animals treated with spironolactone (AbSpi, nâ¯=â¯20) and sham controls (Sham, nâ¯=â¯29). After 12â¯weeks, animals underwent echocardiographic and electrophysiological evaluation and were sacrificed for histological (atrial fibrosis) and Western blotting (TGF-ß1, collagen I/III, connexin 43 and CaV1.2) analysis.RESULTS:
Mild LV dysfunction and marked atrial enlargement were noted in both ablated groups. AF inducibility (episodes ≥2â¯s) increased in the Ab group compared to sham animals (31/36, 86%; vs. 15/29, 52%; pâ¯=â¯0.005), but did not differ from the AbSpi group (16/20, 80%; pâ¯=â¯NS). Sustained AF (>30â¯s) was also more frequent in the Ab group compared to shams (56% vs. 28%; pâ¯=â¯0.04). Spironolactone reduced atrial fibrosis (pâ¯<â¯0.01) as well as TGF-ß1 (pâ¯<â¯0.01) and collagen I/III (pâ¯<â¯0.01) expression but did not affect connexin 43 and CaV1.2 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.
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MEDLINE
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Año:
2018
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Article