Kay Matthew, Swift Luther, Martell Brian, Arutunyan Ara, Sarvazyan Narine
Department of Pharmacology and Physiology, George Washington University, 2300 Eye Street NW, Washington, DC 20037, USA.
Am J Physiol Heart Circ Physiol. 2008 May;294(5):H2400-5. doi: 10.1152/ajpheart.01158.2007. Epub 2008 Feb 29.
We studied the origins of ectopic beats during low-flow reperfusion after acute regional ischemia in excised rat hearts. The left anterior descending coronary artery was cannulated. Perfusate was delivered to the cannula using an high-performance liquid chromatography pump. This provided not only precise control of flow rate but also avoided mechanical artifacts associated with vessel occlusion and deocclusion. Optical mapping of epicardial transmembrane potential served to identify activation wavefronts. Imaging of NADH fluorescence was used to quantify local ischemia. Our experiments suggest that low-flow reperfusion of ischemic myocardium leads to a highly heterogeneous ischemic substrate and that the degree of ischemia between adjacent patches of tissue changes in time. In contrast to transient ectopic activity observed during full-flow reperfusion, persistent ectopic arrhythmias were observed during low-flow reperfusion. The origins of ectopic beats were traceable to areas of high spatial gradients of changes in NADH fluorescence caused by low-flow reperfusion.
我们研究了在离体大鼠心脏急性局部缺血后的低流量再灌注期间异位搏动的起源。左冠状动脉前降支被插管。使用高效液相色谱泵将灌注液输送到插管。这不仅提供了对流速的精确控制,还避免了与血管闭塞和再通相关的机械伪影。心外膜跨膜电位的光学映射用于识别激活波前。NADH荧光成像用于量化局部缺血。我们的实验表明,缺血心肌的低流量再灌注导致高度异质性的缺血底物,并且相邻组织块之间的缺血程度随时间变化。与全流量再灌注期间观察到的短暂异位活动相反,在低流量再灌注期间观察到持续性异位心律失常。异位搏动的起源可追溯到低流量再灌注引起的NADH荧光变化的高空间梯度区域。