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目的研究慢性心房颤动(房颤)患者心房肌中血管紧张素转换酶(ACE)和血管紧张素受体AT1R、AT2RmRNA表达改变及其对房颤心房结构重构的影响。方法选取进行人工瓣膜置换术的风湿性心脏病房颤病人24例为研究组,风湿性心脏病窦性心律病人12例为对照组。上述病人术前均进行经胸超声心动图检查,于手术时取左心耳心肌标本,应用放射免疫法检测心肌组织中血管紧张素Ⅱ(AngⅡ)含量,采用RTPCR方法检测心房肌中ACE、AT1R、AT2R、及Ⅰ/Ⅲ型胶原(collagenⅠ/Ⅲ)各基因mRNA水平,并与超声指标作相关性分析。结果与对照组比较,房颤组左心耳心肌组织中AngⅡ含量显著增加(P<0.05);胶原Ⅰ、胶原Ⅲ、AT1R、AT2RmRNA的表达水平显著升高(P<0.05),并与房颤持续时间、左心房内径以及AngⅡ含量等指标具有显著相关性(P<0.05)。而ACEmRNA的表达无显著改变。结论慢性房颤患者心房肌局部肾素血管紧张素系统(RAS)激活参与了房颤时心房结构重构,是心房肌间质纤维化的主要机制。
Objective To investigate the changes of angiotensin converting enzyme (ACE) and AT1R, AT2R mRNA expression in atrial myocardium of patients with chronic atrial fibrillation (AF) and their effects on atrial fibrillation remodeling. Methods Twenty-four patients with rheumatic heart disease and atrial fibrillation who underwent prosthetic valve replacement were selected as study group and 12 patients with rheumatic heart disease and sinus rhythm as control group. The patients underwent transthoracic echocardiography preoperatively, left atrial appendage myocardial samples were taken during operation, and the content of angiotensin Ⅱ (AngⅡ) in myocardium was detected by radioimmunoassay. The levels of ACE, AT1R, AT2R and collagen Ⅰ / Ⅲ mRNA levels were determined and correlated with the ultrasound parameters. Results Compared with the control group, the content of AngⅡ in the left atrial appendage myocardium increased significantly (P <0.05), while the expression of collagen Ⅰ, collagen Ⅲ, AT1R and AT2R mRNA increased significantly (P <0.05) Time, left atrial diameter and AngⅡ content were significantly correlated (P <0.05). There was no significant change in ACE mRNA expression. Conclusion Atrial local renin-angiotensin system (RAS) activation in atrial fibrillation in patients with chronic atrial fibrillation is involved in atrial structural remodeling, which is the main mechanism of atrial fibrosis.