15 February 2018
The heart has its own unique electrical system. Its function is to synchronise the contractions effectively.
Managed by an orchestra conductor
The leader of the electrical heart system is situated at the top of the heart, in the right atrium. A cluster of cells called sino-atrial node is in fact the natural pacemaker for the heart. This node is responsible for all heartbeats as well as the frequency, or rate.
An organised electrical transmission
The electricity generated is transmitted to the atria following different steps of the electrical system: an electrical "gatekeeper" and a rapid conduction network in the ventricles.
The heart is not always as regular as clockwork.
Respiratory or sinus arrhythmia
By being very attentive to the heartbeat and by taking the pulse, we can notice, especially with younger people, that the heartbeat increases slightly when inhaling and decreases when exhaling.
This benign arrhythmia is called sinus arrhythmia.
The electrocardiogram records this:
Inhaling accelerates the heart, exhaling slows it down
Sinus arrhythmia originates from the leader of the system, the sino-atrial node. The respiratory variation of the heartbeat is caused by the right atrium that recognizes a surplus of blood coming from the veins after inhaling.
Breathing in make the lungs expand but the heart also calls for blood via the large veins. This increase in blood volume accelerates the orchestra conductor so that the heart works faster.
Inversely, breathing out reduces the blood volume in the right atrium and causes a decrease in the pulse.
This slight irregularity is considered normal.