What is an Arrhythmia?
Arrhythmia refers to any disturbance in the normal rhythm or rate of the heartbeat. This can involve heartbeats that are excessively fast, slow, or irregular due to abnormal electrical impulses.
When the heart's rhythm is disrupted, it cannot effectively pump blood throughout the body. This can lead to inadequate blood supply to vital organs such as the lungs and brain, potentially causing organ dysfunction or even failure
Types of Arrhythmias
- Atrial Fibrillation
- Atrial Flutter
- Bradycardia
- Conduction Disorders
- Premature Contraction
- Tachycardia
- Ventricular Fibrillation
The human heart consists of four chambers:
- Two atria: The upper chambers (the right atrium and the left atrium).
- Two ventricles: The lower chambers (the right ventricle and the left ventricle).
Four valves regulate blood flow within the heart:
- Tricuspid valve: Located between the right atrium and right ventricle.
- Pulmonary valve: Located between the right ventricle and the pulmonary artery.
- Mitral valve: Located between the left atrium and left ventricle.
- Aortic valve: Located between the left ventricle and the aorta.
These valves, composed of leaflets or cusps (two for the mitral valve, three for the others), ensure unidirectional blood flow by opening and closing in response to pressure differences within the heart chambers.
The heart's function relies on a coordinated sequence of contractions: The atria contract first, followed by the ventricles, propelling blood to the lungs and throughout the body. This synchronized contraction is essential for efficient blood circulation and the proper functioning of all organs.
Electrical system of the heart
The heartbeat is initiated by an electrical impulse originating from the sinoatrial (SA) node, often referred to as the "heart's pacemaker." This impulse spreads through the atrial tissue, reaching the atrioventricular (AV) node.
From the AV node, the electrical signal travels down the bundle of His and through the Purkinje fibers, triggering the contraction of the ventricles. This coordinated sequence of electrical activity ensures a regular and efficient heartbeat.
In adults, a normal resting heart rate typically ranges from 60 to 100 beats per minute.
Electrocardiography (ECG or EKG) is a non-invasive diagnostic test that records the heart's electrical activity. By analyzing the ECG, healthcare professionals can identify arrhythmias and other heart conditions.
Abnormal heart rhythms (arrhythmias)
Arrhythmias refer to any disturbance in the normal electrical rhythm of the heart. This can manifest as variations in the speed or regularity of the heartbeat.
While some arrhythmias are brief and inconsequential, others can significantly disrupt the heart's function. If the heart rate becomes excessively fast (tachycardia, typically over 100 beats per minute in adults) or excessively slow (bradycardia, typically below 60 beats per minute), the heart's ability to pump blood effectively can be compromised.
Causes of Arrhythmias
Arrhythmias can arise from various factors, including:
- Disruptions in the electrical conduction system: Delays or blockages in the pathway of electrical signals can disrupt the normal rhythm.
- Ectopic pacemakers: Areas of the heart other than the sinus node may spontaneously generate electrical impulses, interfering with the normal pacemaker function.
- Heart tissue abnormalities:
- Changes in blood flow to the heart.
- Damage to the heart's electrical system.
- Scarring or stiffening of heart tissue.
- External factors:
- Excessive exertion, strain, or stress.
- Imbalances in fluids, hormones, or electrolytes.
- Certain medications.
An arrhythmia can occur when:
- The heart's natural pacemaker (the sinus node) malfunctions: This can involve problems with the rate or rhythm of electrical signals generated by the sinus node.
- The normal pathway for electrical signals is disrupted: This can include delays, blockages, or changes in the way electrical impulses travel through the heart.
- Another part of the heart takes over as the pacemaker: This is known as an ectopic pacemaker, and it can lead to irregular heart rhythms.