关键词： 心肌顿抑；超声心动描记术；亚硝酸异三梨醇酯；多巴酚丁胺

【摘要】目的对比小剂量多巴酚丁胺(Dobu)及其合用硝酸酯二维超声心动图(2DE)试验识别冬眠心肌的准确性和安全性。方法陈旧性心肌梗塞患者23例，行小剂量Dobu及其合用硝酸酯试验后成功接受了冠状动脉血运重建术(CRV)，术后3个月左右复查2DE。用16-段半定量分析法对左室各节段收缩运动和增厚情况给予分级记分。将两试验检出的冬眠心肌节段与CRV术后相应节段收缩改善的实际对比，计算识别冬眠心肌的准确性。比较血运重建术前后两试验的结果，并评价安全性。结果小剂量(3、5μg*kg^-1*min^-1)Dobu合用硝酸酯试验识别冬眠心肌的敏感性、特异性和准确性分别为85%～86%、84%和84%～85%，虽与单用Dobu(3、5、10 μg*kg^-1*min^-1)各剂量组间差异均无显著性，但已与Dobu 10μg*kg^-1*min^-1的86%、80%和85%相当；且使冬眠心肌收缩改善2分节段百分比显著高于同剂量Dobu单用时(P均＜0.05)，尤其在Dobu 5μg*kg^-1*min^-1合用硝酸酯时已达单用Dobu 10μg*kg^-1*min^-1时的水平(66.3% vs 74.6%，P＞0.05)，而又无Dobu 10μg*kg^-1*min^-1诱发心肌缺血的副作用。结论小剂量(3、5μg*kg^-1*min^-1) Dobu-硝酸酯2DE试验比单用Dobu时使冬眠心肌收缩作用更强、又更安全，是识别冬眠心肌较为理想而可靠的方法。

Comparison of low-dose dobutamine and its combination with nitrate echocardiography in identifying hibernating myocardium

Yang Yuejin, Gao Runlin, Tian Jun, et al. Cardiovascular Institute and Fu Wai Heart Hospital, CAMS and PUMC, Beijing 100037

【Abstract】ObjectiveTo compare the accuracy and safety of low-dose dobutamine (Dobu) and its combination with nitrate two -dimensional echocardiography (2DE) in identifying hibernating myocardium.MethodsLow-dose (3,5and 10μg*kg^-1*min^-1) Dobu (Dobu-3,5 and 10) and combined low-dose (3 and 5μg*kg^-1*min^-1) Dobu (Dobu-3 and 5) with isosorbide dinitrate (ISDN, 240-300μg*min^-1) 2DE tests were conducted in 23 patients with old myocardial infarction who were scheduled to undergo coronary revascularization (CRV). CRV was successful in all patients including angioplasty of 17 and bypass surgery of 6, and the follow-up 2DE were also done about 3 months after CRV. Left ventricular regional wall motion and thickening in each segment were graded and scored using a 16-segment model and semiquantitative analysis method. The detected hibernating myocardium, defined as 1 or 2 scores decreasing in at least two adjacent abnormal segments after the two tests, were compared with the post-CRV actual contractile improvement of corresponding segments to calculate the sensitivity, specificity and accuracy of the tests for identifying hibernating myocardium. Comparison was also made between the two tests.ResultsThe sensitivities, specificities and accuracies of Dobu-nitrate 2DE for identifying hibernating myocardium were 85-86%, 84% and 84-85%, respectively, which were not significantly different from those of different low dose Dobu tests, though were equivalent to 86%,80% and 85%, respectively of Dobu -10 alone. The percentages of marked (2 scores) contractile improving segments among detected hibernation segments on Dobunitrate tests were significantly higher than those on the same dose of Dobu tests (both P＜0.05); particularly with the percentages on combined Dobu-5 with nitrate being equivalent to that on Dobu-10 alone (66.3% vs 74.6%, P＞0.05), and without occurrence of ischemia as induced by Dobu-10.ConclusionCombined low-dose (3-5 μg*kg^-1*min^-1) Dobu with nitrate 2DE test is more prominent in strengthening the contractility of hibernating myocardium for detection and safer than the same dose Dobu test alone, indicating a relatively reliable and ideal method for identifyfing hibernating myocardium.

【Key words】myocardium stunningechocardiographyisosorbide dinitratedobutamine

小剂量(5～10μg*kg^-1*min^-1)多巴酚丁胺(Dobu)二维超声心动图(2DE)试验是识别冬眠心肌的可靠方法已得到公认^［1，2］。本研究旨在对比小剂量Dobu及其合用硝酸酯的2DE试验识别冬眠心肌的准确性和安全性。

资料与方法

一、病例选择

陈旧性心肌梗塞患者23例，均在完成小剂量Dobu及其合用硝酸酯2DE试验后2周内成功地接受了包括梗塞相关冠状动脉(IRCA)在内的冠脉血运重建术(coronary revascularization,CRV),其中球囊扩张或支架置入17例，外科冠状动脉旁路移植术6例。23例中，男22例，女1例，平均年龄51.6±10.8岁；梗塞部位：前、侧壁8例，下、后壁14例，前壁＋下壁1例，心功能均为NYHA II级。左室造影均有室壁节段运动异常(RWMA)存在，平均射血分数为54.6±10.3%;冠状动脉造影显示单支病变(冠脉内径狭窄≥50％)8例，双支病变8例，3支病变7例；IRCA的病变狭窄约80% 1例，约90%～95% 13例, 99%～100% 9例。

二、方法

1.小剂量Dobu及其合用硝酸酯2DE试验：患者先停用β-受体阻滞剂、钙拮抗剂和硝酸酯类至少18小时。然后，在安静状态下测心率、血压取三次均值；用惠普100CF超声心动图仪，以2.5MHz探头探测并录象记录标准左室长轴、短轴和心尖切面2DE图象作对照。接着用微量泵静脉输注亚硝酸异三梨醇酯(ISDN)注射液(德国许瓦兹大药厂生产)，以60μg*kg^-1*min^-1起始并递增该量至收缩压降低5～10mmHg(1mmHg=0.133kPa)或心率增加3～5次/分，或达最大量300μg/min时维持输注；同时用另一微量泵连续分级静脉输注Dobu 3和5μg*kg^-1*min^-1，每一剂量维持5分钟后重复记录心率、血压和标准2DE图象。停药休息30～40分钟，待心率、血压恢复至用药前静息水平时重新开始Dobu3、5、10μg*kg^-1*min^-1连续分级输注，也在每级剂量维持5分钟后重复记录心率、血压和2DE图象。每例均在CRV术后3个月左右行2DE随诊检查。所有2DE检查均由同一位有经验的操作者完成。

2.2DE图象的处理和分析：同一分析者间隔2周，两次对所有2DE图象进行分析。按国际通用的16节段半定量法将左室各节段收缩运动和增厚情况分级记分为：正常或增强: 1分，轻度减弱: 2分，严重减弱: 3分，消失: 4分，和矛盾运动: 5分。并计算出每例室壁节段运动指数(WMSI)来评价整体收缩功能。WMSI＝各节段记分之和/总节段数，正常为1。对两次记分不一致节段，与第二位分析者达成一致。同一人两次分析节段运动的变异性为5.6%，两位分析者间的变异性为12.4%。

将用药或CRV术后≥2个相邻异常节段有收缩功能改善(减少1分)或明显改善(减少2分)定为冬眠心肌，否则为坏死瘢痕心肌。以CRV术后冬眠心肌收缩功能改善为标准，对比小剂量Dobu单用和合用硝酸酯的2DE试验识别冬眠心肌的准确性和安全性。

3.统计学分析：用药前、后比较用配对t检验，率的比较用U检验。

结果

一、小剂量Dobu及其合用硝酸酯试验时心率、血压、WMSI变化(表1)和副作用对比

23例中，ISDN平均用量为294.8±17.3μg*min^-1，有3例未接受单用Dobu试验，又2例未完成Dobu-10μg*kg^-1*min^-1剂量。单用Dobu-3、5μg*kg^-1*min^-1时，仅血压显著增高(P＜0.05～0.001)，Dobu-10μg*kg^-1*min^-1时，心率和血压均显著增加(P＜0.05～0.001)。Dobu-3、5μg*kg^-1*min^-1合用ISDN时,血压均显著降低(P＜0.05～0.001)，心率均显著增快(P＜0.01～0.001)。WMSI在用药和CRV术后均显著降低(P均＜0.001)，提示左室整体收缩功能显著改善。

Dobu 5和10μg*kg^-1*min^-1时，诱发心绞痛2例(10%)，而Dobu合用硝酸酯时无一例心绞痛发生。

二、小剂量Dobu及其合用硝酸酯试验使冬眠心肌节段收缩运动增强作用对比(表2)

小剂量Dobu及其合用硝酸酯两试验检出冬眠心肌节段百分比在各剂量组间差异均无显著性，但其中收缩改善2分(减少2分)节段百分比均随Dobu剂量增加而显著递增(P＜0.05～0.001)，在Dobu合用硝酸酯时也均比同剂量Dobu单用时显著增加(P均＜0.05)，尤其在Dobu-5μg*kg^-1*min^-1合用硝酸酯时已达单用Dobu-10μ