Electrical Conduction System Of The Heart: What It Is And How It Works
Have you ever wondered how the heart beats? For the heart to beat and pump blood to the different parts of our body, it operates through the so-called electrical conduction system of the heart.
In this article we will briefly explain what the human heart is like and how it works, What does the electrical conduction system of the heart consist of and how does it operate? Finally, we will talk about arrhythmias, an alteration that occurs when this system fails.
Before talking about the electrical conduction system of the heart, and how it works, we are going to briefly explain what the heart is and what its functions are.
The word heart comes from the Latin cor, and It is the main organ of the circulatory system The circulatory system serves to internally transport the different substances that living beings need to live: hormones, nutrients, oxygen, carbon dioxide…
Regarding its characteristics, the heart is a hollow muscular organ. It works like a pump, pushing blood through the arteries, with the purpose of distributing it throughout our body. Its size is that of a fist, and its weight is between 250 and 300 grams (in women) and 300 and 350 grams (in men). That is approximately 0.4% of our body weight. At an anatomical level, the heart is located in the center of the thoracic cavity, between the lungs.
Thus, the heart is the pump of muscle tissue, which what it does is pump blood through the body. On the other hand, The electrical conduction system of the heart coordinates the contraction of the different chambers from the heart.
What structures are part of the heart, and therefore, the electrical conduction system of the heart? It is about 4:
Now, let’s see how the electrical conduction system of the heart works.
electrical conduction system of the heart
The electrical conduction system of the heart has the main function of allow the blood pumped by the heart to be distributed throughout the body (that is, it is pumped throughout the body). Coordinates the contractions of the chambers of the heart so that it beats correctly.
More specifically, it is a system that allows the impulse generated by a node of the heart, the sinus node, to propagate and stimulate an important cardiac muscle, the myocardium. In this way, the latter contracts.
Thus, this system involves a series of myocardial coordinations, which make the heart contract effectively and, as we said, so the blood is pumped throughout the body.
Components, location and operation
The main components of the electrical conduction system of the heart are two, the sinoatrial (SA) or sinus node and the atrioventricular node. We are going to explain what each of them consists of, and how the electrical conduction system of the heart operates through these nodules (that is, how the heart beats):
1. Sinoatrial (SA) node
You could say that the sinoatrial node is the heart’s natural pacemaker. This module also has other names, such as sinus node, Keith and Flack node, or heart pacemaker At an anatomical level, the SA is located in the upper posterior part of the right atrium of the heart, just at the entrance to the superior vena cava.
Regarding its characteristics, it is the largest cardiac pacemaker, and its shape is oval. It is in this node where the electrical impulse is born, which moves and spreads through the atria It does this through pathways called internodal pathways, causing the atria to contract.
In healthy adults, the sinus node discharges at a rate of 60 impulses per minute (60 contractions per minute); That is, the electrical stimulus is generated regularly between 60 and 100 times per minute.
2. Atrioventricular (AV) node
This is when the electrical impulse reaches the next node, the atrioventricular node (also called the Aschoff-Tawara node). Its size is 40% of the size of the previous node, the sinus. It has an oval shape, and It is located in the left part of the right atrium specifically in a structure called the interatrial septum.
Almost always (in 90% of cases), the atrioventricular node is irrigated by a branch located in the right coronary artery. Said nodule It has two types of innervations: sympathetic and parasympathetic
It is in the atrioventricular node where the electrical impulse (or electrical wave) stops for less than 1 second (specifically, for 0.13 seconds).
And after that…?
After this pause of the electrical impulse in the atrioventricular node, said impulse spreads through the Bundle of His, a bundle of fibers which acts as a bridge between the nodule and the branches of the ventricles.
This beam is divided into two more branches: the right and the left. On the left another division appears: the anterior left fasciculus, the posterior left fasciculus and the middle or septal fasciculus. From In this last fascicle, the electrical impulse is distributed to the ventricles, through the Purkinje fibers fibers that allow ventricular contraction.
Abnormal functioning of the heart’s electrical conduction system
We have talked about how the electrical conduction system of the heart works in normal or healthy conditions, that is, when our heart beats normally and the different parts of the body receive blood pumping normally.
But… what happens when there is a malfunction? Then situations or phenomena such as arrhythmias occur.
Arrhythmias
An arrhythmia is a heart rate or heart rhythm disorder ; In these cases, it may happen that the heart beats faster than usual (what we speak of as tachycardia), that it beats too slowly (bradycardia) or that it does so irregularly.
That is, arrhythmias involve abnormal heartbeats. The arrhythmias themselves They may not be harmful, although they are sometimes a sign of underlying problems or an imminent danger to our health.
When and why do arrhythmias occur? They can occur in different cases and situations. The three most frequent are the following:
Symptoms
As we see, when the electrical conduction system of the heart fails, arrhythmias can appear. But, What symptoms does this disorder or alteration of heart rhythm produce? Mainly arrhythmias produce 4 symptoms: feeling of shortness of breath, dizziness, fainting and palpitations.
To evaluate this problem, electrocardiogram (ECG) is used, which allows us to determine and analyze the rhythm of our heart. An ECG consists of a painless examination that allows recording cardiac electrical activity through different electrodes placed on the chest.
Sometimes, when the electrical rhythm is not normal, medication or surgery may even be needed. We should always turn to a specialist doctor to evaluate and treat our case.
