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Atrial fibrillation

life science Maturity 11-13 Next article →

Atrial fibrillation, often called AF, AFib, or A-fib, is a serious type of arrhythmia. An arrhythmia is an abnormal heart rhythm.

Atrial Fibrillation
Atrial Fibrillation

In this condition, the atrial chambers—the top parts of the heart—beat very rapidly and irregularly. It is a form of supraventricular tachycardia, which means a fast heart rate originating above the ventricles. This irregular rhythm can appear in short bursts or become a continuous state. Sometimes, it may even start as another rhythm called atrial flutter before transforming into AF.

Afib ecg
Afib ecg

The mechanism of AF involves chaotic electrical signals within the heart. Often, these bursts of tachycardia start in muscle bundles that extend from the atrium to the pulmonary veins.

Heart conduct atrialfib
Heart conduct atrialfib

Other areas, like the left atrial appendage, the ligament of Marshall, or the ganglionated plexi, can also trigger the rhythm. As the condition becomes more persistent, the left atrium itself can become an independent source of these arrhythmias. This happens because the junction between the pulmonary veins and the left atrium changes over time. Because the heart beats so uncoordinatedly, it can reduce cardiac output. This means the heart cannot pump enough blood to deliver oxygen to the rest of the body.

Symptoms of AF vary widely between different people. Some individuals are asymptomatic, meaning they feel no symptoms at all. Others may experience palpitations, which is the sensation of the heart beating too fast or skipping beats. Other symptoms include lightheadedness, fainting, or shortness of breath. In some cases, the lack of oxygen and blood flow to the brain can cause a loss of consciousness. If the condition leads to congestive heart failure, a person might notice fatigue or swelling in their lower extremities.

Atrial Fibrillation
Atrial Fibrillation

In some instances, the rhythm is only discovered when a person suffers a stroke or a transient ischemic attack (TIA).

Atrial fib stroke
Atrial fib stroke

There are many different risk factors associated with developing AF. High blood pressure and valvular heart disease are common modifiable factors. Other cardiovascular risks include coronary artery disease, cardiomyopathy, and congenital heart disease. Lung-related issues like COPD, obesity, and sleep apnea are also significant. Sleep apnea, in particular, is a very strong predictor of the condition.

RiskFactors
RiskFactors

Lifestyle factors such as tobacco smoking and excessive alcohol intake can increase risk. Interestingly, about half of all cases are not linked to any of these specific risks. Genetics also play a role, as having a first-degree relative with AF increases risk by 40%.

Medical history shows how our understanding of AF has grown. The first known report of an irregular pulse was made by Jean-Baptiste de Sénac in 1749. It took much longer to see the electrical patterns, however. In 1909, Thomas Lewis became the first doctor to document AF using an electrocardiogram, or ECG.

ECG Atrial Fibrillation
ECG Atrial Fibrillation

Today, doctors use the ECG to confirm a diagnosis. A typical ECG for AF shows irregularly spaced QRS complexes and a lack of P waves.

SinusRhythmLabels
SinusRhythmLabels

This electrical map allows healthcare professionals to see exactly how the heart is misfiring.

AF affects a massive number of people globally. As of 2020, it affects more than 33 million people worldwide. In 2014, it affected about 2% to 3% of the population in Europe and North America. The prevalence of AF increases significantly as people age. For those under 50, the rate is only 0.1%. This rises to 4% for those between 60 and 70. For people over 80, the rate reaches 14%.

RiskFactors
RiskFactors

These numbers show why managing the condition is so important for aging populations.

Doctors use several methods to treat and manage AF. They may use rate control to slow the heart rate or rhythm control to restore a normal sinus rhythm.

Heart conduct sinus
Heart conduct sinus

If a person is unstable, doctors might use electrical cardioversion to reset the rhythm during an emergency. Another option is ablation, where doctors destroy small areas of heart tissue to stop the irregular signals.

3D Medical Animation of Left Atrial Appendage Occlusion
3D Medical Animation of Left Atrial Appendage Occlusion

For those at high risk of stroke, doctors often prescribe anti-clotting medications like warfarin. While these help prevent strokes, they can also increase the risk of major bleeding. Healthy changes like weight loss and more physical activity can also help reduce the burden of the disease.

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🖼️ Images & Media (9)
File:SinusRhythmLabels.svg
SinusRhythmLabels.svg
File:3D Medical Animation of Left Atrial Appendage Occlusion.jpg
3D Medical Animation of Left Atrial...
File:Atrial Fibrillation.png
Atrial Fibrillation.png
File:ECG Atrial Fibrillation.jpg
ECG Atrial Fibrillation.jpg
File:RiskFactors.jpg
RiskFactors.jpg
File:Afib ecg.jpg
Afib ecg.jpg
File:Atrial fib stroke.jpg
Atrial fib stroke.jpg
File:Heart conduct atrialfib.gif
Heart conduct atrialfib.gif
File:Heart conduct sinus.gif
Heart conduct sinus.gif
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