The effects of class I antiarrhythmic drugs on the automaticity of isolated guinea pig pulmonary vein myocardia were investigated using microelectrode and voltage clamp methods. All of the drugs examined reduced the maximum rate of rise of automatic action potentials. The firing frequency and rate of diastolic depolarization were decreased by aprindine, flecainide and propafenone, but not by cibenzoline, disopyramide and pilsicainide, which correlated with blockade of the sodium current component induced by ramp depolarization mimicking the diastolic depolarization. In conclusion, class I antiarrhythmic drugs which block the diastolic sodium current component inhibit the automaticity of the pulmonary vein myocardium.

使用微电极和电压钳方法研究了I类抗心律失常药物对离体豚鼠肺静脉心肌自动化的影响。所有检查的药物均降低了自动动作电位的最大上升速度。阿普林定，氟卡尼和普罗帕酮降低了舒张期去极化的频率和频率，但环苯胺，二吡酰胺和比西卡因却没有降低，这与模拟舒张期去极化的斜坡去极化引起的钠电流成分的阻断有关。总之，阻断舒张钠电流成分的I类抗心律不齐药物会抑制肺静脉心肌的自律性。