【摘要】 目的 :应用彩色组织多普勒 (CTD)技术评价左室前壁心内膜下心肌缺血时的速度阶差 (VG)变化及对小剂量多巴酚丁胺 (DOB)的反应。方法 :7只开胸犬 (2 0± 3) kg将左前降支 (L AD)血流减半造成心内膜下心肌缺血模型 ,并予小剂量 DOB (5μg/kg/min)静脉输注。以 CTD观察心内膜下心肌缺血及应用 DOB后心内膜下心肌的 VG变化。结果 :L AD血流减半后 CTD显示前壁心内膜下心肌 VG显著降低 ,由收缩期 (S期 )的 (2 .9±1.1) /sec降至 (1.8± 0 .7) /sec,舒张期 (D期 )的 (4.9± 1.7) /sec降至 (2 .8± 0 .6 ) /sec (P<0 .0 1) ,射血时间(ET)由 (174 .7± 36 .6 ) ms延长至 (180 .1± 4 7.8) ms (P<0 .0 5 )。应用小剂量 DOB后 VG恢复至 S期 (3.0±0 .5 ) /sec和 D期的 (4.9± 1.3) /sec(与缺血时比 P<0 .0 1) ,ET延长至 (2 2 0 .1± 5 9.3) ms(与缺血时比 P<0 .0 5 )。结论 :CTD为评价心内膜下心肌缺血的敏感指标。心内膜下心肌缺血时应用小剂量 DOB可改善心内膜下心肌 VG,但 ET延长更多还原

【Abstract】 Objective:To quantify left ventricular anterior wall subendocarial myocardial function during acute ischemia using color tissue Doppler(CTD)velocity gradient (VG) and to observe the response of ischemic myocardium to low dose dobutamine (DOB)infusion.Methods:7 open chest dogs(20±3kg)were chosen with left anterior descending artery(LAD)blood flow half occluded to make anterior wall subendocardial myocardial ischemic model.3 minutes after ischemia dobutamine with 5μg/kg/min dosage was infused.CTD was introduced to observe subendocardial myocardial VG at baseline,during ischemia and with DOB infusion.Results:Subendocardial myocardial VG of anterior wall was markedly decreased from 2 9±1 1/sec to 1 8±0 7/sec in systole and 4 9±1 7/sec to 2 8±0 6/sec in diastole( P <0 01).The ejection time(ET)prolonged from 174 7±36 6ms to 180 1±47 8ms( P <0 05).After DOB infusion subendocardial myocardial VG was increased to 3±0 5/sec in systole and 4 9±1 3/sec in diastole( P <0 01 vs.ischemia).Whereas ET was further elongated to 220 1±59 3ms( P <0 05 vs.ischemia).Conclusions:CTD is an optimized method to evaluate subendocardial myocardial ischemia during controlled ischemic canine model,with both systolic and diastolic subendocardial myocardial VG decreased markedly.Low dose DOB infusion can increase subendocardial myocardial VG but ET was further elongated.更多还原