title: Beneficial effects of an angiotensin-II receptor blocker on structural atrial reverse-remodeling in a rat model of ischemic heart failure.
abstract: The remodeling of gap junctions may affect their conduction properties and contribute to the maintenance of atrial fibrillation. The significance of the role of angiotensin-II receptor blockers (ARBs) in upstream therapy is not clear. This study was performed to investigate the effects of ARBs on atrial remodeling in a heart failure model. A model of heart failure was established or sham surgery performed in 24 Sprague-Dawley male rats. The rats were divided into sham, heart failure and heart failure-ARB groups. In the ARB group, 30 mg/kg of losartan was administered each day for 4 weeks. Echocardiography was performed at the baseline and 4 weeks following the surgery. An atrial fibrillation induction study and histological and immunohistochemical evaluation were performed 4 weeks after surgery. The increase in the left atrial diameter of the heart failure-ARB group was smaller than that of the heart failure group (P=0.028). The atrial fibrillation inducibility and duration of induced atrial fibrillation were not different between the heart failure and heart failure-ARB groups. Masson's trichrome staining revealed less fibrosis in the heart failure-ARB group compared with the heart failure group. Immunohistochemical staining and western blot analysis for connexin 43 showed a lower expression level in the heart failure-ARB group compared with that in the heart failure group. In a rat model of ischemic heart failure the ARB losartan had structural and histological atrial reverse-remodeling effects. However, its role as an electrical stabilizer requires further study.
authors.affiliation: Department of Cardiovascular Medicine, The Heart Center of Chonnam National University Hospital, Chonnam National University Research Institute of Medical Science, Gwangju 501-757, Republic of Korea.
authors.forename: Namsik
authors.initials: N
authors.lastname: Yoon
authors.forename: Jeong Gwan
authors.initials: JG
authors.lastname: Cho
authors.forename: Kye Hun
authors.initials: KH
authors.lastname: Kim
authors.forename: Keun Ho
authors.initials: KH
authors.lastname: Park
authors.forename: Doo Sun
authors.initials: DS
authors.lastname: Sim
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Hong
authors.forename: Hyung Wook
authors.initials: HW
authors.lastname: Park
authors.forename: Ju Han
authors.initials: JH
authors.lastname: Kim
authors.forename: Youngkeun
authors.initials: Y
authors.lastname: Ahn
authors.forename: Myung Ho
authors.initials: MH
authors.lastname: Jeong
authors.forename: Jong Chun
authors.initials: JC
authors.lastname: Park
keywords: angiotensin-II receptor blocker; atrial fibrillation; atrial reverse-remodeling; heart failure