Austin R E, Smedira N G, Squiers T M, Hoffman J I
Cardiovascular Research Institute, University of California, San Francisco 94143.
Am J Physiol. 1994 Jun;266(6 Pt 2):H2542-53. doi: 10.1152/ajpheart.1994.266.6.H2542.
We analyzed patterns of left ventricular perfusion in arrested hearts without coronary tone and in the same hearts while beating with and without coronary tone. We used microspheres in anesthetized dogs to measure blood flow in 384 regions (averaging 140 mg wet wt) from the subendocardium, midwall, and subepicardium before and during intracoronary infusions of adenosine (beating without tone) or lidocaine and adenosine (arrest without tone). Mean coronary pressure was held constant at 80 mmHg. Changes in regional flow with arrest (vs. beating without tone) were surprisingly variable (range -28 to +124%) and exhibited substantial within-layer heterogeneity, suggesting that local differences in contractility, stresses, or strains limit maximum coronary flow. Regional flows in beating hearts with tone did not correlate with flows in the same hearts without tone, beating or not (r2 < or = 0.03; not significant). Flow patterns during beating with tone also demonstrated significantly shorter (i.e., the distance at which autocorrelation has decreased to 0.5) within-layer spatial autocorrelations as well as a complete loss of radial flow correlation (e.g., between corresponding subendocardial and subepicardial regions; r2 = 0.01). Thus neither coronary anatomy (assessed during arrest without tone) nor the mechanical effects of contraction (beating without tone) appear to influence myocardial perfusion when vasomotor tone is present.
我们分析了无冠脉张力的停搏心脏以及有和无冠脉张力时跳动的同一心脏的左心室灌注模式。我们在麻醉犬中使用微球测量在冠状动脉内输注腺苷（无张力跳动）或利多卡因和腺苷（无张力停搏）之前和期间，从心内膜下、心肌中层和心外膜下384个区域（平均湿重140mg）的血流。平均冠状动脉压力维持在80mmHg恒定。停搏时（与无张力跳动相比）区域血流变化出人意料地多变（范围为-28%至+124%），并表现出显著的层内异质性，提示收缩性、应力或应变的局部差异限制了最大冠状动脉血流。有张力跳动心脏的区域血流与同一心脏无张力时跳动或不跳动的血流均无相关性（r2≤0.03；无显著性）。有张力跳动期间的血流模式还显示层内空间自相关显著缩短（即自相关降低至0.5时的距离），以及径向血流相关性完全丧失（例如，在心内膜下和心外膜下相应区域之间；r2 = 0.01）。因此，当存在血管舒缩张力时，无论是冠脉解剖结构（在无张力停搏期间评估）还是收缩的机械效应（无张力跳动）似乎都不影响心肌灌注。
