Duo G S, Hoff P, Kupersmith J
Department of Medicine, Mount Sinai School of Medicine, City University of New York.
Am Heart J. 1989 Apr;117(4):854-61. doi: 10.1016/0002-8703(89)90623-6.
We studied interactions between action potential duration (APD) disperse zones using a double compartment bath in which an APD lengthening solution (Ni++ 2 mmol/L, in Tyrode's solution) was added to one compartment (which contained a portion of the fiber labeled "segment A") followed by addition of an APD shortening solution (6 to 10 mmol/K+) to the other compartment ("segment B"). Standard microelectrode techniques were used in canine Purkinje fibers. With Ni++ in segment A, there was a dispersion in APD measured at both 50% (APD50) and 95% (APD95) of repolarization. After selective addition of K+ to segment B, APD50 dispersion remained constant while APD95 dispersion increased, which indicated a change in the slope of repolarization, a factor with possible arrhythmogenic potential. In addition, a characteristic transitional action potential was seen adjacent to the partition. This had a timely and normally sloping early repolarization followed by a much more gradually sloping shelf. Premature action potentials arising during this shelf had diminished upstrokes. Results of these experiments may be useful in evaluating APD dispersion in relation to arrhythmias.
我们使用双室浴槽研究动作电位时程（APD）离散区之间的相互作用，在一个室中加入APD延长溶液（2 mmol/L Ni++，溶于Tyrode溶液）（该室包含标记为“节段A”的部分纤维），然后在另一个室（“节段B”）中加入APD缩短溶液（6至10 mmol/K+）。在犬浦肯野纤维中使用标准微电极技术。节段A中有Ni++时，在复极化的50%（APD50）和95%（APD95）时测量的APD存在离散。向节段B选择性添加K+后，APD50离散保持不变，而APD95离散增加，这表明复极化斜率发生变化，这是一个可能具有致心律失常潜力的因素。此外，在隔板附近可见特征性的过渡动作电位。它有及时且正常斜率的早期复极化，随后是斜率更平缓的平台期。在此平台期出现的早搏动作电位其上升支减小。这些实验结果可能有助于评估与心律失常相关的APD离散。
