依那普利干预肾素-血管紧张素系统对老龄鼠心房颤动诱发率的影响

目的研究依那普利对老龄鼠心房颤动(简称房颤)诱发率的影响。方法雄性老龄Wistar大鼠(12月龄)随机分为对照组(n=12)和实验组(n=13),对照组常规饲养,实验组加喂依那普利。3个月后,描记体表Ⅰ导联心电图,测量心率和P波时限。在体研究右房有效不应期(ERP)、房间传导时间(IACT)和心房对刺激的反应。用放免法测量血浆和心房组织血管紧张素Ⅱ(AngⅡ)浓度。取心房组织制作切片,测量纤维组织占总区域的百分比。结果实验组较对照组P波时限和IACT缩短(P均<0.01)。实验组房颤诱发率较对照组低30.8%(4/13)vs75%(9/12),P=0.027]。实验组左、右房组织匀浆AngⅡ浓度较对照组降低(P均<0.01)。实验组大鼠左房和右房纤维化程度均较对照组明显减轻(P均<0.01)。结论老龄鼠长期应用依那普利后房颤诱发率降低,这可能是由于依那普利降低了心房纤维化程度,改善了心房传导。

Effect of intervening renin-angiotensin system with enalapril on inducible atrial fibrillation in old rats

Objective To study the changes of inducible atrial fibrillation （AF） in old rats. Methods Old male Wistar rats （ 12 months old）were randomly divided into control group（ n = 12） and experiment group（ n = 13 ）. Rats in control group were fed routinely. Rats in experiment group were fed with enalapril besides normal diet. After three months, lead of body surface ECG was recorded, P wave duration and heart rate were measured. Right atrium effective refractory period（ERP） ,interatrial conduction time（IACT） and atrial response to burst atrial pacing were studied in vivo. Plasma angiotensin Ⅱ level and atrial tissue angiotensin Ⅱ level were determined by radioimmunoassay. Sections were cut from the tissue of atrium, and the ratio of the area occupied by interstitial to the total area was measured. Results Contrast to control group,rats in experiment group had shorter P wave duration and IACT than the rats in control group（ both P 〈0.01 ）. AF were induced in 9 rats in control group and 4 rats in experiment group. Inducible AF rate was lower in experiment group than that in control group（ 30.8% vs 75% ; P = 0.027）. Tissue angiontensin II concentration of right and left atrium significantly decreased in experiment group than that in control group （ all P 〈 0. 01 ）. Interstitial atrial fibrosis in experiment group was significantly lightened than that in control group. Conclusion Inducible AF rate decreases in old rats chronically treated with enalapril. This maybe result from enalapril decreasing atrial fibrosis degree, improving atrium conduction.