title: An Angiotensin receptor blocker prevents arrhythmogenic left atrial remodeling in a rat post myocardial infarction induced heart failure model.
abstract: This study investigated the role of angiotensin II receptor blocker in atrial remodeling in rats with atrial fibrillation (AF) induced by a myocardial infarction (MI). MIs were induced by a ligation of the left anterior descending coronary artery. Two days after, the rats in the losartan group were given losartan (10 mg/kg/day for 10 weeks). Ten weeks later, echocardiography and AF induction studies were conducted. Ejection fraction was significantly lower in the MI rats. Fibrosis analysis revealed much increased left atrial fibrosis in the MI group than sham (2.22 ± 0.66% vs 0.25 ± 0.08%, P = 0.001) and suppression in the losartan group (0.90 ± 0.27%, P 0.001) compared with the MI group. AF inducibility was higher in the MI group than sham (39.4 ± 43.0% vs 2.0 ± 6.3%, P = 0.005) and significantly lower in losartan group (12.0 ± 31.6%, P = 0.029) compared with the MI. The left atrial endothelial nitric oxide synthase (NOS) and sarco/endoplasmic reticulum Ca(2+)-ATPase levels were lower in the MI group and higher in the losartan group significantly. The atrial inducible NOS and sodium-calcium exchanger levels were higher in the MI and lower in the losartan group significantly. Losartan disrupts collagen fiber formation and prevents the alteration of the tissue eNOS and iNOS levels, which prevent subsequent AF induction.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kosin University Gospel Hospital, Busan, Korea.
authors.forename: Hyun-Su
authors.initials: HS
authors.lastname: Kim
authors.forename: Chi-Wan
authors.initials: CW
authors.lastname: No
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Goo
authors.forename: Tae-Joon
authors.initials: TJ
authors.lastname: Cha
mesh_terms: D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use*; D000818:Animals; D001281:Atrial Fibrillation / Q000517:prevention & control*; D064752:Atrial Remodeling; D004195:Disease Models, Animal; D005355:Fibrosis; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology*; D007150:Immunohistochemistry; D019808:Losartan / Q000627:therapeutic use*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications* / Q000000981:diagnostic imaging; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011945:Receptors, Angiotensin / Q000737:chemistry / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D014463:Ultrasonography
chemical_list: D057911:Angiotensin Receptor Antagonists; D011945:Receptors, Angiotensin; D019831:Sodium-Calcium Exchanger; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D019808:Losartan
keywords: Angiotensin Receptor Blocker; Atrial Fibrillation; Fibrosis; Heart Failure