A Modified Beagle Model of Inducible Atrial Fibrillation Using a Right Atrium Pacemaker

Figures

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  Fig. 1. Electrocardiography (ECG). A) Baseline ECG traced by electrophysiological recorder; B) atrial fibrillation after burst stimulation traced by electrophysiological recorder; C) one-minute ECG; D) 12-lead ECG.

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  Fig. 2. Transthoracic echocardiographies. The left image is the sinus rhythm (SR). The right image is atrial fibrillation (AF) induced by stimulation.

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  Fig. 3. Hematoxylin-eosin (HE) and Masson’s stainings of the right atrium (×400). A) HE staining in the control group showed normal cell form and connections. B) HE staining in the atrial tachycardia pacing (ATP) group showed abnormal cell connections. There was more extracellular matrix. C) Masson’s staining in the control group. D) Compared with that of the control group, Masson’s staining in the ATP group showed significant blue fiber tissue.

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  Fig. 4. Immunohistochemistry (IHC) of the right atrium (×400). The brown colour means the target protein. The IHC showed that the collagen I, collagen III, and connective tissue growth factor (CTGF) levels in the atrial tachycardia pacing (ATP) group were significantly more evident than in the control group.

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  Fig. 5. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis of the messenger ribonucleic acid (mRNA) expression of collagen I (A), collagen III (B), and connective tissue growth factor (CTGF) (C) in right atrium tissue after eight weeks of atrial tachycardia pacing (ATP). Compared with those of the control group, the collagen I, collagen III, and CTGF mRNA expression levels in the ATP group were significantly increased. *Means P<0.05.

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  Fig. 6. Western blot analysis of collagen I (A), collagen III (B), and connective tissue growth factor (CTGF) (C) protein levels from right atrial tissues eight weeks after the atrial tachycardia pacing (ATP). Compared with the levels in the control group, the collagen I and CTGF protein expression levels in the ATP group were significantly increased. D) Gray scale maps. *Means P<0.05. GAPDH=glyceraldehyde-3-phosphate dehydrogenase