Relationship Between Atrial Extracellular Signal-Regulated Kinase and Atrial Fibrosis in Patients With Rheumatic Heart Disease and Atrial Fibrillation.

Department of Cardiology,Renmin Hospital of Wuhan University,Wuhan 430060,ChinaTo study the relationship between extracellular signal regulated kinase (ERK) and atrial fibrosis in patients with rheumatic heart disease(RHD) and atrial fibrillation(AF),atrial tissue was obtained from the right atrial appendage during open heart surgery in 33 patients with RHD.ERK 2 mRNA and activated ERK 2 were semi quantified by reverse transcription polymerase chain reaction and immunohistochemistry.The content of atrial tissue angiotensinⅡ(AngⅡ) and atrial collagen volume fraction(CVF) were analyzed respectively by radioimmunoassay and histochemistry.Results:The atrial CVF and AngⅡ content of patients with paroxysmal AF or chronic AF were significantly increased compared with patients in sinus rhythm (10.44%±1.83%,15.01%±2.30% vs 7.48%±1.26%;10.17±1.73, 12.13 ±1.95 vs 6.69±1.18 ng/mg, P all0.01),and the atrial CVF and AngⅡ content of patients with chronic AF were significantly increased compared with patients with paroxysmal AF( P0.01,P 0.05).The mRNA of ERK 2 in patients with paroxysmal AF or chronic AF was significantly higher than that in patients with sinus rhythm (1.209±0.285,1.305±0.263 vs 0.923±0.271, P 0.05, P 0.01),no difference between paroxysmal AF and chronic AF( P 0.05).The protein of activated ERK 2 in atrial interstial cells of patients with paroxysmal AF or chronic AF was significantly increased compared with patients in sinus rhythm (0.252±0.075,0.288±0.063 vs 0.175±0.074, P all0.01),there was no significantly difference between paroxysmal AF and persistent AF( P 0.05).Conclusions:An increase in the amounts of activated ERK in atrial interstial cells may contribute as a molecular mechanism for the development of atrial fibrosis in patients with RHD and AF.Atrial fibrillation