Shannon R P, Komamura K, Shen Y T, Bishop S P, Vatner S F
Department of Medicine, Harvard Medical School, Beth Israel Hospital, Boston 02115.
Am J Physiol. 1993 Sep;265(3 Pt 2):H801-9. doi: 10.1152/ajpheart.1993.265.3.H801.
The purpose of the present investigation was to examine coronary flow and vasodilator reserve in conscious, chronically instrumented dogs with pacing-induced heart failure, a model of severe biventricular cardiomyopathy devoid of significant hypertrophy. Twelve dogs were studied after 28 days of rapid right ventricular pacing and were compared with six sham-operated controls. Left ventricular (LV) average transmural flow was significantly less in conscious dogs with pacing-induced heart failure, whereas the endocardial-to-epicardial flow ratio was not significantly different. In response to near maximal coronary vasodilation with adenosine, subepicardial coronary flow and vasodilator reserve were preserved in congestive heart failure (CHF), yet there was evidence of impaired subendocardial flow and vasodilator reserve, and the endocardial-to-epicardial ratio was significantly less. When the markedly elevated LV end-diastolic pressure was normalized in heart failure, there was restoration of subendocardial coronary flow reserve and a normalization of the endocardial-to-epicardial ratio. Thus, in CHF, there is impaired coronary flow and vasodilator reserve that is selective to the subendocardium of the LV. At this point in the heart failure process, this impairment is not associated with structural changes but is a consequence of the marked elevation in LV end-diastolic pressure.
本研究的目的是检测患有起搏诱导性心力衰竭的清醒、长期植入仪器的犬的冠状动脉血流和血管舒张储备，该模型为严重双心室心肌病模型，无明显肥厚。12只犬在快速右心室起搏28天后接受研究，并与6只假手术对照组进行比较。起搏诱导性心力衰竭的清醒犬左心室（LV）平均透壁血流显著减少，而心内膜与心外膜血流比值无显著差异。在用腺苷使冠状动脉接近最大程度舒张时，充血性心力衰竭（CHF）中的心外膜下冠状动脉血流和血管舒张储备得以保留，但有证据表明心内膜下血流和血管舒张储备受损，且心内膜与心外膜比值显著降低。当心力衰竭中显著升高的LV舒张末期压力恢复正常时，心内膜下冠状动脉血流储备恢复，心内膜与心外膜比值正常化。因此，在CHF中，冠状动脉血流和血管舒张储备受损，且这种损伤对LV的心内膜下层具有选择性。在心力衰竭过程的这一阶段，这种损伤与结构变化无关，而是LV舒张末期压力显著升高的结果。
