title: Preventive Effects of the Angiotensin-II Receptor Blocker on Atrial Remodeling in an Ischemic Heart Failure Model of Rats.
abstract: OBJECTIVE
  It is widely known that angiotensin-II receptor blockers (ARBs) have reverse remodeling effects in atrium. Although atrial fibrillation is frequent in ischemic heart failure clinically, experiments to demonstrate ARB's effects on atrial remodeling in a heart failure model are rare.
  
  
  METHODS
  A heart failure model and a sham-operated group were formed in 25 Sprague-Dawley male rats of roughly 260 g in weight. Ischemic heart failure models were obtained via ligation of the left anterior descending coronary artery. In the ARB group, 30 mg/kg of losartan was administrated over a day for 4 weeks. Echocardiography was performed to measure left ventricle ejection fraction and left atrial diameter (LAD) at the baseline and 4 weeks after the operation. 4 weeks later, histologic and immunohistochemical evaluation were performed.
  
  
  RESULTS
  Groups were divided into the sham group, heart failure group, and heart failure-ARB group. We maintained 5 rats in each group for 4 weeks after operation. The decrease of left ventricular ejection fraction in the heart failure-ARB group was less than that in the heart failure group (p=0.023). The increase of LAD in the heart failure-ARB group was less than that in the heart failure group (p=0.025). Masson's trichrome stain revealed less fibrosis in the heart failure-ARB group. Immunohistochemical stain and western blot for connexin 43 showed less expression in the heart failure-ARB group.
  
  
  CONCLUSIONS
  In the ischemic heart failure model of rats, structurally and histologically, the ARB, losartan, has atrial reverse-remodeling effects. However, electrically, its role as an electrical stabilizer should be studied further.
authors.affiliation: Department of Cardiology, Chonnam National University Hospital, Gwangju, Korea.
authors.forename: Namsik
authors.initials: N
authors.lastname: Yoon
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: Youn
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: Jeong Gwan
authors.initials: JG
authors.lastname: Cho
authors.forename: Jong Chun
authors.initials: JC
authors.lastname: Park
keywords: Angiotensin-II receptor blocker; Atrial fibrillation; Atrial remodeling