Pennock J L, Pierce W S, Waldhausen J A
Surgery. 1976 May;79(5):523-33.
A controlled study was undertaken to evaluate the relationship between myocardial oxygen consumption (MVO2) and epicardial S-T segment improvement in an ischemic heart preparation during left ventricular (LV) bypass. Twelve mongrel dogs were prepared with left ventricular-aortic bypass, coronary sinus cannulation, and a multiple point epicardial electrocardiographic technique. The left anterior descending coronary artery was ligated low (Group I) or high (Group II) after baseline studies. After ischemic baseline studies, increasing degrees of LV bypass were performed at a constant mean aortic pressure and heart rate. The final infarct size was determined by the nitroblue tetrazolium staining technique. Group I--a significant reduction in the average (S-T) segment elevation occurred during 50 to 59 percent of LV bypass during which MVO2 was reduced 10.9 percent from controls. A maximum S-T reduction of 75 percent occurred during LV decompression during which MVO2 was reduced 52.8 percent from controls. The final infarct size for Group I was 9.8 +/- 0.9 Gm. per 100 Gm. of LV. Group II--a significant reduction in S-T segment elevation occurred only after 90 to 99 percent LV bypass was achieved during which MVO2 was reduced 28.1 percent from controls. LV decompression produced a maximum S-T reduction of 63 percent during which MVO2 was reduced 50.2 percent from controls. The final infarct size for Group II was 21.1 +/- 0.4 Gm. per 100 Gm of LV. This study indicates that larger degrees of bypass are required to decrease the ischemic areas encountered in larger infarctions. LV decompression is most beneficial in reducing ischemic myocardium surrounding large infarctions.
进行了一项对照研究，以评估左心室（LV）转流期间缺血性心脏标本中心肌耗氧量（MVO2）与心外膜S-T段改善之间的关系。12只杂种犬接受了左心室-主动脉转流、冠状窦插管和多点心外膜心电图技术制备。在基线研究后，左前降支冠状动脉低位结扎（I组）或高位结扎（II组）。在缺血性基线研究后，在恒定的平均主动脉压和心率下进行不同程度的LV转流。最终梗死面积通过硝基蓝四唑染色技术确定。I组——在50%至59%的LV转流期间，平均（S-T）段抬高显著降低，在此期间MVO2较对照组降低10.9%。在LV减压期间，S-T段最大降低75%，在此期间MVO2较对照组降低52.8%。I组的最终梗死面积为每100克LV 9.8±0.9克。II组——仅在达到90%至99%的LV转流后，S-T段抬高才显著降低，在此期间MVO2较对照组降低28.1%。LV减压期间，S-T段最大降低63%，在此期间MVO2较对照组降低50.2%。II组的最终梗死面积为每100克LV 21.1±0.4克。本研究表明，需要更大程度的转流来减少较大梗死中遇到的缺血区域。LV减压对减少大梗死周围的缺血心肌最有益。
