Heart Electrical System - Parts, Functions, and Types

Introduction

The heart is a nonstop engine that keeps the human being alive. In order to maintain the efficiency of the heart’s standard functions, a specialized and restrictive network of cells conducts electrical impulses from the brain to different sections of the heart and vice versa. This electrical network of the heart is referred to as the cardiac electrical system or the heart’s electrical system.

The cardiac cells are unique in their function and have the potential to generate strong electrical impulses. These impulses then get distributed throughout the structure of the heart. Every cell in the body can generate electrical impulses, but the cardiac cells can produce electrical activity at specific intervals and at particular speeds. This is the chief reason the different chambers of the heartbeat are in synchrony with each other, forming a pattern of heartbeat called lub-dub.

What Are the Parts of the Electrical System of the Heart?

The heart is divided into four main divisions. The upper division has two parts, called the right and left atrium. The lower division has two parts as well, called the right and left ventricles. Atrioventricular conduction is the normal electrical impulse conduction between the atrium and the ventricles. The AV node, or the atrioventricular node, is a tiny structure located in the heart. The chief function of this atrioventricular node is to control the flow of the heart’s electrical signals transmitted from the atrium to the ventricles. On the other hand, this HPS or the His-Purkinje System has the duty to rapidly conduct the electrical signals to the ventricles.

Mentioned below are the different critical parts of the heart's electrical system.

• The sinoatrial or SA node is a group of cells that behave as the heart’s natural pacemaker and is located in the right atrium. The upper chambers begin to squeeze blood due to the sinoatrial node.

• The atrioventricular or AV node is placed within the septum that divides the left and right atrium. The atrioventricular node is smaller than the sinoatrial node and has a slower speed in conducting electrical impulses. This is beneficial since the ventricles get a sufficient amount of time to expand and accommodate blood flow inside it.

• The Bundle of His is located in the center of the heart and works at lightning speed to conduct the electrical impulses within the heart.

• Bundle branches are the division of the bundle of his into two parts to transfer the electrical signals toward the outer structure of the heart and the ventricles.

• Purkinje fibers are the further dense continuation of the bundle branches.

• The His-Purkinje system refers to the collective structure and function of the bundle of His, bundle branches, and the Purkinje fibers. They form the shape of an inverted umbrella.

What Are the Functions of the Electrical System of the Heart?

The heart works throughout life without any pause or rest. In order to function while an individual is asleep or awake, certain parts of the autonomic nervous system help the vital organs function normally without the consciousness of the individual.

Mentioned below are the critical functions of the electrical system of the heart.

• Firing electrical impulses to continue the conduction of the heart.

• Activation of the electrical impulse within the cardiac muscle.

• Squeezing the chambers of the heart to pump out blood and create a heartbeat.

• Decrease or increase the heartbeat as per rest or while active.

• Maintaining the electrical cascade of the heart’s structure.

What Are the Different Types of Disorders Related to the Heart’s Electrical Activity?

• Atrial tachycardia is a kind of arrhythmia, which means an abnormal rhythm of the heart caused due to strange electrical activity of the atrium. Generally, it occurs due to excessive signals sent to the upper part of the heart that may occur due to various underlying conditions or even a pacemaker malfunctioning.

• VT, or ventricular tachycardia, is a kind of arrhythmia, which means an abnormal rhythm of the heart caused due to strange electrical activity of the ventricles. A normal heartbeat originates due to an electrical impulse arising from the sinus node. When this is altered, an unusual electric signal keeps repeating, leading to the ventricle beating rapidly.

• Atrioventricular dissociation is a defect in the cardiac conduction of the heart. In this condition, both the upper chambers and lower chambers of the heart do not work in synchrony. One of the most severe complications of atrioventricular dissociation is a total blockage of the heart.

• AV block or atrioventricular block is a disturbance in the normal electrical conduction of the heart, specifically between the atrium and ventricle. A delay or staggered conduction through the atrioventricular node may lead to calcification or fibrosis and can thus cause a complete atrioventricular block.

• AV-nodal reentrant tachycardia or atrioventricular nodal reentry tachycardia (AVNRT) is a common heart rhythm malfunctioning condition. In this condition, the heart rhythm is abnormally fast. The reason for this is a chain effect of tachycardia in the ventricles above the His-Purkinje fibers.

• Arrhythmia or irregular rhythm of the heart.

• Bradycardia is the condition when an individual suffers from low heart rates. Several reasons may lead to bradycardia.

What Are the Signs and Symptoms of a Malfunctioning Electrical System in the Heart?

All the disorders that occur within the electrical system of the heart have more or less the same set of clinical manifestations. Mentioned below are the several signs and symptoms of a malfunctioning electrical system in the heart.

• Palpitations.

• Dizziness.

• Shortness of breath.

• Lightheadedness.

• Weakness.

• Passing out.

• Fatigue.

• Low levels of stamina.

• Exhaustion.

• Pounding feeling in the chest.

• Chest pain.

• Syncope.

• Loss of endurance.

• Discomfort around the waist.

Conclusion

The heart’s electrical system is the backbone of the heart’s regular functioning. Electricity or electrical impulse from the autonomic nervous system, along with a specialized set of cardiac cells, travels to the bottom of the heart and spreads out, then travels along with the external parts of the heart. This electrical cascade forms a loop and this is how the heart is able to pump a sufficient amount of blood out of the heart.