Atrial Fibrillation

Atrial Fibrillation - What it is

Atrial fibrillation is caused by abnormal electrical activity in the upper chambers which causes an irregular and rapid rhythm in the lower chambers.

Atrial fibrillation (AF) is an abnormal heart rhythm (arrhythmia) characterised by rapid and irregular beating. This is caused by unusual electrical activity in the upper chambers (atria) of the heart which causes the lower chambers (ventricles) to beat quickly and irregularly. It is the most common heart rhythm problem and can occur in patients of any age though it is more commonly seen in older patients. AF is not immediately life-threatening but may result in heart failure in acute and chronic settings. AF also predisposes a patient to blood clot formation in the atria, particularly the left atrial appendage. In an event of clot embolisation from the heart to the brain, a stroke occurs.

Understanding Atrial Fibrillation

Types of Atrial Fibrillation

Atrial fibrillation (AF) can be classified into four categories based on severity.

1) Paroxysmal atrial fibrillation (occasional): The AF comes and goes spontaneously, and usually last for a few minutes to hours. Patients may feel intermittent palpitations with this.

2) Persistent: The AF might last for more than seven days and require treatment with medication to restore a normal heart rhythm.

3) Long-standing persistent: The AF occurs often for a period of more than a year.

4) Permanent: AF is continuously occurring and the patient accepts that this will be long-term.

Possible complications of Atrial Fibrillation

If atrial fibrillation (AF) is left untreated, it can lead to life-threatening complications like strokes or heart failure.

1) Stroke
Atrial fibrillation increases the risk of stroke by five times.

For patients with AF, the upper chambers of their heart are not pumping effectively. As such, blood flow is slow or stagnant which may cause blood clots to form. If these blood clots travel through the blood stream and block the arteries in the brain, a stroke can happen.

2) Heart Failure

AF can weaken the heart by making the heart work harder and reducing its ability to pump blood around the body efficiently. As the heart beats rapidly, it is unable to completely fill up with oxygen-rich blood to transport to the brain and other parts of the body, leading to fatigue, shortness of breath, and even causes fluid to build up in the lungs, legs, ankles and feet.

Atrial Fibrillation - Symptoms

Some common symptoms of atrial fibrillation (AF) are:

Palpitations or heart flutters
Shortness of breath
Chest discomfort
Fainting spells
Dizziness
Fatigue and exercise intolerance

It is important to note that some people with AF, especially those who are older, might not experience symptoms. Please visit a doctor if you have occasional chest pains or have an abnormally high or low heart rate.

Atrial Fibrillation - How to prevent?

Treatment and control of underlying medical or cardiac problems may help one reduce the risk of developing atrial fibrillation (AF). This includes:

Managing high blood pressure (hypertension): Taking medication and making lifestyle changes to manage hypertension reduces the risk of AF.
Exercising regularly: Moderate-intensity exercise lowers blood pressure and reduces the risk of coronary artery disease that could lead to development AF.
Eating a heart healthy diet: Eat more whole grains, vegetables and fruits and cut down on salt and solid fats. This reduces one’s risk of medical conditions such as coronary artery disease which are associated with higher risks of experiencing AF.

Eating a heart healthy diet can reduce the risk of many conditions associated with higher risks of experiencing atrial fibrillation

Maintaining a healthy weight: One should aim to maintain a healthy Body Mass Index (BMI) under 27 kg/m2. This will help to reduce the effects or complications associated with AF.
Smoking cessation: Quitting smoking reduces the risks of AF.
Managing stress: This reduces one’s risk of experiencing an abnormal heart rhythm like AF.
Reducing alcohol or caffeine consumption: Drinking too much caffeine or alcohol, especially binge drinking, can trigger incidences of AF.

Atrial Fibrillation - Causes and Risk Factors

The exact cause of atrial fibrillation (AF) remains unknown though there are various medical conditions and individual risk factors that have been associated with AF.

Existing heart conditions: Those who suffer from heart diseases (such as coronary artery disease or heart valve disease), heart failure or have a history of heart attack, have increased risks of AF.
Chronic conditions: Those with chronic conditions such as sleep apnoea, diabetes mellitus or lung problems have a higher risk of AF.
High blood pressure (hypertension): High blood pressure increases the risk of AF.
Overactive thyroid gland (hyperthyroidism): Some patients who suffer from thyroid diseases may experience abnormal heart rhythms (arrhythmias) including AF.
Obesity: Those who are obese are more likely to suffer from AF.
Excessive alcohol or caffeine consumption: Binge drinking alcohol or consuming to much caffeine can lead to incidences of AF.
Smoking: Smoking can increase the risk of AF.
Genetics: Those with a family history of AF are more likely to suffer from the condition.
Age: Anyone below the age of 50 years old has a 0.1% chance of suffering from AF but this risk increases to 10% for those above the age of 80 years old.

Atrial Fibrillation - Diagnosis

There are many diagnostic tests available for the diagnosis of atrial fibrillation (AF) such as:

Checking pulse: This is a simple test that can help with the detection of AF and can be done by the doctor as part of a physical examination or by yourself. If you are checking your own pulse, make sure you do not smoke or consume caffeine before taking the measurement.
Electrocardiogram (ECG): This is the main diagnostic test for AF. It measures your heart rhythm and electrical activity, which shows if the heart is beating too quickly. If you have AF, the ECG should show absent P waves and rapid disorganised electrical activity.
Holter: A Holter monitor is a portable ECG recorder which measures your heart rhythm for 24 to 48 hours. This is used because a typical ECG is rather short and may not be able to capture a moment of AF.
Blood tests: Help check for possible conditions that might lead to AF.
Echocardiogram: An ultrasound of the heart allows doctors to look at the functions and structures of the heart and valves to detect any structural abnormalities.

Aside from these tests, a thorough medical history will be obtained from patients with suspected or known AF.

Atrial Fibrillation - Treatments

There are two main targets of atrial fibrillation (AF) treatment: rate or rhythm control and stroke prevention.

A) Heart Rate or Heart Rhythm Control

Heart rate or heart rhythm can be controlled via medications or procedures.

1) Medications

Medical therapy with drugs can be given to slow down the heart rate or convert AF back to the normal sinus rhythm.

2) Procedures

Electrical cardioversion: An electric shock will be delivered to the heart to convert an irregular or rapid heart rhythm (arrhythmia) back to a normal heart rhythm.
Catheter ablation: A thin tube called an electrode catheter is used to conduct an electrophysiology study (EPS) which locates the site causing the abnormal heart rhythm. A radiofrequency energy is then delivered to ablate (or destroy) areas of abnormal electrical activity.

B) Stroke Prevention

Stroke prevention is achieved by anticoagulation with strong blood thinning agents. There are two types of anti-clotting medications in Singapore: Warfarin and Direct-acting Oral Anti-Coagulants (DOACs). Both medications effectively reduce the risk of stroke though they might slightly increase the risk of both external and internal bleeding. Patients taking Warfarin will need to go for regular blood tests to ensure that they are taking an appropriate dose that is unique to them.

Alternatively, treatment for the heart’s left atrial appendage is also available in the form of the WATCHMAN® left atrial appendage device, which is a permanent implant designed to keep harmful sized blood clots from entering your blood stream. This is typically recommended in patients who have had significant bleeding issues with anticoagulation.

Your doctor will assess and evaluate the extent of your condition, before recommending the most suitable treatment. Some factors that will be considered include:

Age
Current symptoms
Existing health conditions
Risk of stroke
The type of AF you have

Atrial Fibrillation - Preparing for surgery

Atrial Fibrillation - Post-surgery care

Atrial Fibrillation - Other Information

Watch our videos on Atrial Fibrillation:

理解心房颤动 / Understanding Atrial Fibrillation (Chinese version)

Memahami Fibrilasi Atrium Bersama / Understanding Atrial Fibrillation (Malay version)

Overview

Cardiology,

Electrophysiology ＆ Pacing,

Abnormal Heart Rhythm/Arrhythmia

Article contributed by Department of Cardiology, National Heart Centre Singapore

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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