Which rate indicates the heart's electrical impulses are generated by the Purkinje Fibres?

The heart's electrical impulses generated by the Purkinje Fibres occur at a rate of 20-40 beats per minute. The Purkinje Fibres are part of the heart's conduction system, specifically responsible for transmitting impulses to the ventricles, triggering their contraction. This low heart rate indicates that the Purkinje Fibres can function as a pacemaker when higher centers like the sinoatrial (SA) node and atrioventricular (AV) node fail to do so.

In normal physiology, the SA node is the primary pacemaker of the heart, typically firing at a rate of 60-100 beats per minute. If there's a disruption in higher pacemaker activity, the AV node may take over at a rate of 40-60 beats per minute. However, if the conduction system needs backup due to failure of these nodes, the Purkinje Fibres will take over, but at the much slower rate of 20-40 beats per minute. This is crucial for understanding cardiac rhythm and the implications of different heart rates, especially in emergency settings or during arrhythmias.