Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation

Luís Felipe Neves dos Santos; Ednei Luiz Antônio; Andrey Jorge Serra; Amanda Yoshizaki; Larissa Emília Seibt; Flávio Alves da Silva; Gisele Kruger Couto; Luciana Venturini Rossoni; Paulo José Ferreira Tucci; Angelo A. de Paola; Guilherme Fenelon

doi:10.1016/j.ijcha.2018.09.003

September 22, 2018IJC Heart & VasculatureOpen Access

Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation

View Full Paper

Ask AI

Bookmark

Share

Why the study?

Does left ventricle radiofrequency ablation-induced heart failure promote atrial fibrillation vulnerability and structural remodeling in rats, and does spironolactone mitigate these effects?

Structured PICO

Does left ventricle radiofrequency ablation-induced heart failure promote atrial fibrillation vulnerability and structural remodeling in rats, and does spironolactone mitigate these effects?

P

Population

Wistar rats (n=85 total: 36 RF-induced CHF, 20 CHF treated with spironolactone, 29 sham controls)

I

Intervention

Left ventricle radiofrequency (RF) ablation to induce congestive heart failure (CHF), with a subgroup receiving spironolactone

C

Comparator

Sham controls

O

Outcome

Atrial fibrillation (AF) inducibility (episodes ≥2 s) and sustained AF (>30 s)surrogate

A rat model of heart failure induced by LV radiofrequency ablation exhibits pronounced atrial structural remodeling and enhanced AF vulnerability, providing a useful substrate for studying AF in CHF.

Implication

RF ablation-induced HF heightens AF vulnerability in rats; leaves open spironolactone's preventive role and model utility for future studies.

Abstract

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. 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 CaV1.2) analysis. 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 CaV1.2 expression. 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.