What is the rate of the Bundle of His/Purkinje fibers?

What is the rate of the Bundle of His/Purkinje fibers?

• A. 20-40 BPM
• B. 30-50 BPM
• C. 40-60 BPM
• D. More than 40 BPM

Answer: (A)

The rate of the Bundle of His and Purkinje fibers serves as the intrinsic pacemaker of the heart when both the sinoatrial (SA) node and the atrioventricular (AV) node fail to maintain normal rhythm. This backup pacemaker has a firing rate typically ranging from 20 to 40 beats per minute (BPM), operational in situations where higher pacemaker sites are not functioning properly. Given the physiological roles of these structures, the Bundle of His and Purkinje fibers are critical for conducting impulses through the ventricles, ensuring coordinated contraction. While other pacemaker cells, such as those in the atria and AV junction, fire at higher rates, the specific rate for the Bundle of His/Purkinje fibers being between 20 and 40 BPM is a well-established parameter in cardiac physiology. The other choices reflect inaccurate ranges compared to the known physiological data on these conduction tissues. Understanding this critical rate helps in interpreting cardiac rhythms and potential arrhythmias that can arise from disturbances in conduction within the heart.

The rate of the Bundle of His and Purkinje fibers serves as the intrinsic pacemaker of the heart when both the sinoatrial (SA) node and the atrioventricular (AV) node fail to maintain normal rhythm. This backup pacemaker has a firing rate typically ranging from 20 to 40 beats per minute (BPM), operational in situations where higher pacemaker sites are not functioning properly.

Given the physiological roles of these structures, the Bundle of His and Purkinje fibers are critical for conducting impulses through the ventricles, ensuring coordinated contraction. While other pacemaker cells, such as those in the atria and AV junction, fire at higher rates, the specific rate for the Bundle of His/Purkinje fibers being between 20 and 40 BPM is a well-established parameter in cardiac physiology.

The other choices reflect inaccurate ranges compared to the known physiological data on these conduction tissues. Understanding this critical rate helps in interpreting cardiac rhythms and potential arrhythmias that can arise from disturbances in conduction within the heart.