Duncker D J, McFalls E O, Krams R, Verdouw P D
Laboratory for Experimental Cardiology, Erasmus University Rotterdam, The Netherlands.
Am J Physiol. 1992 Jun;262(6 Pt 2):H1744-51. doi: 10.1152/ajpheart.1992.262.6.H1744.
In view of variable results on maximal coronary blood flow in stunned myocardium, we studied the pressure-maximal coronary flow (PMCF) relationship in stunned myocardium in 12 anesthetized swine by using intracoronary adenosine (20 micrograms/kg). Subendocardial systolic segment shortening (SS) measured with sonomicrometry was 19 +/- 5% (means +/- SD) at baseline and 7 +/- 6% (P less than 0.01) at 30 min of reperfusion after 15 min of low-flow ischemia, at which time postsystolic shortening was present. Myocardial stunning increased the slope of the PMCF regression line (alpha PMCF) from 3.34 +/- 1.03 to 3.89 +/- 1.33 ml.min-1.mmHg-1 (P less than 0.01). Atrial pacing at 40 beats/min above spontaneous heart rate (n = 6) further reduced subendocardial SS to 6 +/- 6% (P less than 0.05). Dobutamine (4 micrograms.kg-1.min-1; n = 6) increased subendocardial SS to 13 +/- 5% (P less than 0.05) and abolished postsystolic shortening. Both interventions left alpha PMCF unchanged. In conclusion, myocardial stunning was associated with an increase in alpha PMCF that most likely resulted from the decreased contractile function. The absence of an effect of dobutamine may be due to its predominant action on diastolic function.
鉴于顿抑心肌中最大冠状动脉血流量的结果存在差异，我们通过冠状动脉内注射腺苷（20微克/千克），研究了12只麻醉猪顿抑心肌中的压力-最大冠状动脉血流（PMCF）关系。用超声微测法测量的内膜下收缩期节段缩短（SS）在基线时为19±5%（平均值±标准差），在低流量缺血15分钟后再灌注30分钟时为7±6%（P<0.01），此时存在收缩后缩短。心肌顿抑使PMCF回归线的斜率（αPMCF）从3.34±1.03增加到3.89±1.33毫升·分钟-1·毫米汞柱-1（P<0.01）。以高于自主心率40次/分钟的频率进行心房起搏（n = 6）进一步将内膜下SS降低至6±6%（P<0.05）。多巴酚丁胺（4微克·千克-1·分钟-1；n = 6）使内膜下SS增加至13±5%（P<0.05）并消除了收缩后缩短。两种干预均未改变αPMCF。总之，心肌顿抑与αPMCF增加有关，这很可能是由于收缩功能降低所致。多巴酚丁胺无作用可能是由于其主要作用于舒张功能。
