Objective:To study the expression of angiotensin-converting enzyme(ACE)

extracellular signal-regulated kinase(ERK)

and the changes of atrial fibrosis in patients with rheumatic heart disease(RHD) and atrial fibrillation(AF) treated with angiotensin-converting enzyme inhibitor(ACEI).Methods:Atrial tissues were obtained from the right appendage during open surgery in 35 patients with RHD.The mRNA of ACE and ERK2 were semi-qualified by reverse transcription-ploymerase chain reaction(RT-PCR) and normalized to the glyceraldehyde 3-phosphate dehydrogenase(GAPDH).Western blotting analysis was employed to examine the expressions of ACE and phosphorylated ERK(pERK).Atrial collagen volume fraction(CVF) was detected by Masson’s stain.Results:The mRNA of ACE and ERK2 or the protein of ACE and pERK were significantly increased

and CVF was significantly increased in patients with chronic atrial fibrillation(CAF) compared with sinus rhythm group(SR)( P <0.01 or P <0.05).Compared with CAF patients treated without ACEI

the mRNA of ERK2 and protein of pERK were significantly decreased in CAF patients treated with ACEI( P <0.05)

but there was no difference in ACE

and decrease in CVF was not statistically significant( P >0.05).Conclusion:The expressions of ACE

ERK2 and pERK increase

and fibrosis is more severe in RHD patients with CAF as compared with those with SR.Compared with CAF patients treated without ACEI

the expressions of ERK2 and pERK significantly decrease( P <0.05) and decrease in CVF is detected( P >0.05)in CAF patients treated with ACEI.This suggests that the increasing expression of ERK2 and pERK resulting from local renal angiotensin-converting enzyme system activation mediates the development of atrial fibrosis

and ACEI may contribute to lesser atrial fibrosis in RHD patients with AF.