13 May 2018
The heart has its unique electric system. Its function is to effectively synchronise its contraction.
An electric system managed by a conductor
The conductor of this electric system is situated at the top of the heart, near the right atrium.
It is a cluster of cells called sino-atrial node that is in fact the natural “pacemaker” of the heart. It initiates all the heartbeats and determines their frequency.
An organized electric transmission
The electricity generated is transmitted to the atriums and ventricles by the different steps of the electric system, or the electric customs officer, known as the atrioventricular node, and the rapid conduction network in the ventricles called the Purkinje bundle.
Normal heart rate
It is said that the normal heart rate is between 60 and 100 beats per minute.
It varies in the day
It is normal for the heart rate to vary during a day.
The heart beats more slowly when one is at rest and accelerates during a physical activity or that one lives a stressful situation, for example.
An electrical system influenced by all sides
The heart’s electrical system can be compared to the electrical system of a house. There is a difference, however. It is influenced by certain environmental substances that come from the circulation.
It isn’t insensible to the circulating hormones, to our emotional cerebral reactions, to life-related stress and to all substances and medication consumed by individuals.
In fact, the heart can be over-excited.
Some Arrhythmia can be expressed by more rapid beats than normally. A heart beat higher than 100 per minute is called tachycardia.
The sinus tachycardia
Nature planned that our heart accelerates when necessary.
Physical effort forces our muscles to work. The demand for oxygen and nutriments by the active muscles is therefore more important.
The circulation must be more rapid to ensure these needs and to eliminate the consummation wastes like carbon dioxide.
This tachycardia called “sinusal” is conducted by the sino-atrial node in response to the brain’s commands and to other hormonal mechanisms, for example, substances like adrenaline.
A normal response to a precise situation
The heart is sensible to the needs of the body.
You need more oxygen for your muscles, because you are facing off against a ferocious beast... No problem, your heart can multiply by 5 the blood flow in a few seconds.
It will respond to this intense need by tripling its heart rate and by doubling its contraction vigour.
Imagine that you come really close to having a car accident! Suddenly, you feel your heart is beating very fast and very hard.
This sensation can be accompanied by spasms in your stomach. In this type of situation, the adrenaline is released rapidly by the suprarenal glands. This hormone accelerates the heartbeat and increases the blood pressure. Its effects are short term.
This type of tachycardia is normal
In this case, the resulting tachycardia is said to be “appropriate” and is not really a rhythmic problem.
The medical world calls this tachycardia a “reactive sinus tachycardia.”