Conducting velocity SA node Atria A-Vnode 0.05m/s 0.4m/s 0.02~0.05m/s His bundle Purkinje fiber Ventricle 1.2~2.0m/s 2.0~4.0m/s 1.0m/s Atrioventricular delay(房室延搁): Asynchronization of atrial and ventricular depolarization to provide adequate cardiac outputSA node Atria A-V node 0.05 m/s 0.4 m/s 0.02~0.05 m/s His bundle Purkinje fiber Ventricle 1.2~2.0 m/s 2.0~4.0 m/s 1.0 m/s Conducting velocity Atrioventricular delay（房室延搁）: Asynchronization of atrial and ventricular depolarization to provide adequate cardiac output 44