组织多普勒超声评价阿霉素诱导兔心肌病早期舒张功能改变的实验研究

目的:二尖瓣血流舒张早期速度/二尖瓣环组织多普勒舒张早期速度(E/E’)比值与左室充盈压有良好的相关性,可用来准确评价左室舒张功能异常。本研究利用该指标评价阿霉素所致兔心肌病心肌舒张功能的变化情况。方法:28只日本白兔分为两组,阿霉素组20只,每周静脉注射阿霉素2mg/kg,8w共计16mg/kg以期形成心肌病模型。对照组8只,每周注射相同剂量的生理盐水。分别在第0,4,6,8,10,12w进行常规和组织多普勒超声心动图检查。结果:阿霉素组,在10、12w左室内径显著扩大,左室射血分数和短轴缩短率显著下降(P<0.05)。显著变化最早发现在第10w。二尖瓣环处心肌组织收缩峰值速度在8、10、12w显著降低(P<0.05)。显著变化最早发现在第8w。E?蛐E’比值在6、8、10、12w显著增高(P<0.05)。显著变化最早发现在第6w。对照组常规和组织多普勒超声指标均未发现显著变化(P>0.05)。结论:在阿霉素所致兔心肌病模型中心肌功能降低。E?蛐E’变化早于组织多普勒收缩指标和常规超声心动图指标,为评价左室舒张功能提供了一个敏感可靠的新手段。

Tissue Doppler echocardiography detecting early myocardial relaxation abnormality in Adriamycin-induced cardiomyopathy rabbits

Objective: Transmitral flow velocity to mitral annular velocity ratio(E/E') had a strong positive relationship with left ventricular filling pressure, which presents as a good indicator for evaluating left ventricular diastolic relaxation abnormality. The present study was designed to evaluate myocardial relaxation function changes in an Adriamycin-induced cardiomyopathy model using E/E'. Methods: Twenty-eight Japanese rabbits were divided into two groups. Adriamycin was administered intravenously at a dose of 2mg/kg once a week for 8 weeks(total dose 16mg/kg) in 20 rabbits to induce the cardiomyopathy model. Eight rabbits served as controls receiving the same amount of saline once a week for a total of 8 weeks. Conventional and tissue Doppler echocardiography were performed at baseline, 4th week, 6th week, 8th week, 10th week, 12th week. Results: In the Adriamycin-treated group, LV chamber diameter significantly increased, while ejection fraction and fraction shortening decreased significantly in the 10th and 12th week(P<0.05). The significant changes were first found in the 10th week. Mitral annulus systolic peak velocity by TDE decreased significantly in the 8th, 10th and 12th week(P<0.05). The significant changes were first found in the 8th week. The ratio of E/E' significantly increased in the 6th, 8th, 10th and 12th week(P<0.05). The significant changes were first found in the 6th week. In the control group, no significant changes were found in all parameters by tissue Doppler, conventional echocardiography(P>0.05). Conclusions: Myocardial function was reduced in Adriamycin-induced rabbit model of dilated cardiomyopathy. The relaxation parameter(E/E') by TDE changed earlier than contraction indices by TDE and conventional echocardiography in Adriamycin-induced cardiomyopathy rabbits, which provide a new sensitive and reliable method to evaluate LV relaxation function.