Mechanisms of Arrhythmias 1.心肌自律性增高 (increase in pacemaker rate) 4相自动除极速率加快 阈电位下移 最大舒张电位上升 INa/Ca 1Ca(L) It. Ik Ica(T)Mechanisms of Arrhythmias 1. 心肌自律性增高 (increase in pacemaker rate) 4相自动除极速率加快 阈电位下移 最大舒张电位上升