If the Purkinje fibers, situated distal to the A-V junction, become the pacemaker of the hea, what is the expected hea rate?
If the Purkinje fibers are the pacemaker of the hea, the hea rate ranges between 15 and 40 beats/ min. In contrast, the rate of firing of the A-V nodal fibers are 40 to 60 times a minute, and the sinus node fires at 70 to 80 times per minute. If the sinus node is blocked for some reason, the A-V node will take over as the pacemaker, and if the A-V node is blocked, the Purkinje fibers will take over as the pacemaker of the hea.
30/min
50/min
60/min
70/min
Conducting System of Hea