Camardo J S, Greenspan A M, Horowitz L N, Spielman S R, Josephson M E
Am J Cardiol. 1980 Apr;45(4):856-60. doi: 10.1016/0002-9149(80)90132-0.
The effects of procainamide on strength-interval relations were evaluated in 18 patients. At plasma concentrations of 4.3 to 13.6 micrograms/ml procainamide had minimal effects on threshold current in late diastole, but in early diastole it shifted the strength-interval curve to the right. The basic strength-interval relation (that is, decreasing refractory period as current is increased) was not altered. The control refractory period decreased by a mean of 44 ms as the current was increased from threshold to 10 mA, whereas a mean decrease of 42 ms was observed after procainamide. However, the steep portion of the strength-interval curve(absolute refractory period) was shifted to longer coupling intervals by a mean value of 24 ms. These findings suggest that procainamide may primarily affect active membrane properties, but exert little net effect on passive membrane properties late in diastole.
在18名患者中评估了普鲁卡因胺对强度-间期关系的影响。血浆浓度为4.3至13.6微克/毫升时，普鲁卡因胺对舒张晚期的阈电流影响极小，但在舒张早期，它使强度-间期曲线右移。基本的强度-间期关系（即随着电流增加，不应期缩短）未改变。当电流从阈值增加到10毫安时，对照的不应期平均缩短44毫秒，而使用普鲁卡因胺后平均缩短42毫秒。然而，强度-间期曲线的陡峭部分（绝对不应期）平均右移24毫秒至更长的耦联间期。这些发现表明，普鲁卡因胺可能主要影响细胞膜的主动特性，但在舒张晚期对细胞膜的被动特性几乎没有净效应。
