硝酸甘油对犬心表冠状动脉和心肌微循环血流的影响

Effects of nitroglycerin on coronary blood flow of epicardial coronary artery and myocardial microvasculature in dogs

目的 探讨硝酸甘油 (NTG)对犬心表冠状动脉和心肌微血管血流量的影响。方法 静脉注射NTG 2 0 μg·min-1后 ,应用心肌对比超声心动图 (MCE)测量心肌微血管血流量 ,动脉血流仪测量冠状动脉前降支血流量 ,超声心动图测量心脏腔径和容积。结果 NTG 2 0 μg·min-1对心表冠状动脉和心肌微血管的血流量均无明显影响 [注射NTG前后前降支血流量分别为 :( 13.94± 2 .92 ) ,( 14 .5 7± 4 .73)mL·min-1;A·β值分别为 :( 4 5 .4 9± 14 .2 8) ,( 80 .0 8± 36 .72 ) ,P均 >0 .0 5 ];NTG对心率、血压、平均动脉压、中心静脉压和冠状动脉血管阻力也无明显影响。但可明显减少心脏腔径和心腔容积 ,尤其右心腔径和容积减少更明显 ;与舒张末期容积比较 ,NTG对心脏收缩末期容积影响更大。结论 NTG对心表大冠状动脉和心肌微血管的血流量无影响。其抗心绞痛的作用是通过减少心脏容积和心室壁张力 。

OBJECTIVE: To discuss the effects of nitroglycerin (NTG) on the coronary blood flow (CBF) of epicardial coronary artery and myocardial microvasculature. METHODS; The CBF of left descending coronary artery(LAD) was measured with flowmeter and CBF of myocardial microcirculation was detected with myocardial contrast echocardiography(MCE) in 8 mongrel dogs. RESULTS: NTG 20μg&middotmin-1 had no effects on either CBF of LAD or of myocardial microcirculation [before and after NTG intravenous injection: LAD (13.94 ± 2.92) mL&middotmin-1 versus (14.57 ± 4.73) mL&middotmin-1 and myocardial microcirculation (45.49 ± 14.28) versus (80.08 ± 36.72) respectively, all P>0.05], and heart rate, blood pressure, mean artery blood pressure, central venous pressure, coronary vascular resistance, neither. But NTG decreased cardiac cavity dimension and volume obviously, especially those in right cavity. Compared with end-diastolic volume, NTG reduced the end-systolic volume more significantly. CONCLUSION: NTG had no influence on either CBF of epicardial coronary artery or of myocardial microcirculation, but it may play an anti-angina role via reducing cardiac cavity dimension, volume and ventricular wall tension, furthermore and decreasing myocardial oxygen consumption.