Atrial fibrillation | Manawa tukituki

Normally, your heart beats about 60 to 100 beats per minute when you are at rest, or doing light activities. Usually all of the heart chambers work together in unison. If you have atrial fibrillation (AF), the electrical signals that control your heartbeat are abnormal. These signals cause the upper chambers of your heart (the atria) to beat unevenly and very quickly. In fact, the atria are racing so quickly that the lower heart chambers (the ventricles) can’t quite keep up, and so your heart doesn’t beat in the usual, coordinated way.

This results in an irregular and rapid heart rate, often ranging from 100 to 180 beats per minute. When this happens, the heart cannot pump blood around the body as well as it needs to.

There are three different kinds of atrial fibrillation:

• Paroxysmal AF – This is a type of AF that comes and goes. Episodes can last for minutes, hours or days but not usually longer than a week.
• Persistent AF – AF episodes that last longer than 7 days at a time.
• Long-standing persistent or permanent AF – When your AF has been ongoing for more than a year.

AF is a progressive disease, so it is not uncommon for people with paroxysmal AF to develop persistent or permanent AF over time. 

The causes of atrial fibrillation are not always clear. However, there are a number of things that increase your risk of developing AF. Risk factors  include:

• age – AF can affect adults at any age, but it is more common as people get older, particularly over 65 years
• high blood pressure
• heart disease like coronary artery disease or heart valve disease or heart failure
• heart attack
• being overweight or obese
• chronic obstructive pulmonary disease (COPD)
• diabetes
• drinking large amounts of alcohol over a long period of time
• genetics – atrial fibrillation can sometimes run in families
• overactive thyroid gland
• lung infections such as pneumonia
• sleep apnoea.

Having AF puts you at higher risk of some serious conditions compared to people without AF. For example,

• you are 4–5 times more likely to have a stroke
• you are 3 times more likely develop heart failure (when your heart can't pump enough blood to the rest of your body)
• you are also more likely to have a heart attack or get dementia.

To reduce these risks it is important to treat your AF, even if you don't have AF symptoms (see below).

How does AF cause stroke?

Because the atria are beating unevenly and very quickly, they don’t pump blood through the heart properly. Blood can then pool in the heart and a blood clot may form. If the clot breaks loose and leaves the heart, it can travel via your blood vessels to other organs in your body. If a clot lodges in a blood vessel that supplies your brain and cuts off the blood supply, it causes a stroke. Read more about stroke.

How does AF cause heart failure?

Uncontrolled or very fast AF can put strain on your heart and cause it to weaken. This can cause heart failure. This is a condition when the heart is unable to effectively pump blood around the body. Read more about heart failure.

If you have AF, you may experience palpitations (an awareness of your heart beating or pounding in your chest). Other symptoms include:

• chest pain
• dizziness
• light-headedness
• shortness of breath
• fatigue and tiredness.

Some people have no symptoms at all, and AF is only detected after a healthcare provider checks your pulse and finds it is irregular.

Image credit: Alila Medical Media / 123RF

Occasional missed beats or extra beats between regular beats are very common and usually nothing to worry about, but best discussed with your doctor. AF, on the other hand, has no pattern to it at all and is continuously irregular.

 A quick guide from the British Heart Foundation:

1. Put one of your hands out so you’re looking at your palm.
2. Use the index/first finger and middle finger of your other hand and place the pads of these fingers on the inside of your wrist. You should place them at the base of your thumb near where the strap of a watch would sit.
3. Press lightly and feel the pulse. If you can’t feel anything press slightly harder or move your fingers around until you feel your pulse.
4. Once you’ve found your pulse, continue to feel it for about 20-30 seconds. Feel the rhythm of the pulse and check if it’s regular or irregular.

Listen to these examples or regular and irregular pulse rhythms from the British Heart Foundation.

• Regular pulse rhythm(external link)(external link)
• Irregular pulse rhythm(external link)(external link)

If you or your doctor thinks you have AF, they may check your pulse, blood pressure, how well hydrated you are and your temperature. They may take a blood test.

AF is diagnosed using a simple, painless test called an electrocardiograph (ECG).

• When you have an ECG, small patches connected to wires (electrodes) are placed on your chest to measure the electrical impulses given off by your heart.
• These electrical impulses are recorded on a piece of paper called an ECG strip.
• The abnormal pattern of electrical impulses seen in people with AF is easily detected by the ECG.

However, if you have paroxysmal AF (episodes that come and then go away), your heartbeat may be normal at the time the ECG is recorded. To detect paroxysmal AF, you may need to have a special test called a Holter monitor test.

• A Holter monitor is a portable device that you wear under your clothes.
• It continuously records your heart's electrical impulses for at least 24 hours.

The treatment for AF varies from person to person depending on a number of factors. Treatment will depend on the severity of your symptoms, the cause and duration of your AF, and whether you have any underlying health problems. The main aims of treatment are to:

• prevent blood clots, therefore lowering your risk of having a stroke
• control your heart rate to restore a normal heart rhythm.

Medication

Blood clot prevention

Having AF puts you at high risk of having a stroke due to a blood clot lodging in a blood vessel that supplies your brain. So, preventing blood clots is one of the most important parts of treating AF.

To prevent blood clots, you may be prescribed a type of medicine called an anticoagulant such as warfarin, dabigatranor rivaroxaban. Anticoagulants are medicines that prevent blood clots from forming and stop existing clots from growing bigger. Because anticoagulants stop blood clots, they may cause bleeding. Your doctor will consider your risk of bleeding and whether anticoagulants are suitable for you. Read more about anticoagulants and which anticoagulant is best for you. Aspirin is no longer recommended for preventing blood clots in people with AF.

Rate control

You may be prescribed medicines to slow down the rate (speed) of your heart beating to a normal level. Medicines used to control heart rate include groups of medicines called beta blockers (eg, metoprolol, bisoprolol and carvedilol), or calcium channel blockers (diltiazem and verapamil). If your heart rate is still not settled with beta blockers and calcium channel blockers, your doctor may also add digoxin. 

Rhythm control

If you are not doing so well on the usual rate control medicines, there are some other medication options, eg, amiodarone, sotalol and flecainide. These are usually prescribed by a cardiologist (heart specialist).  

Other treatment options

Instead of medicines, there are other options that your healthcare provider or cardiologist might recommend for you which can restore your heart to a normal rate and rhythm. These procedures are usually done in hospital.

• Electrical cardioversion is sometimes recommended to treat fast or irregular heartbeat. It involves the use of low-energy electrical shocks to trigger your heart into a normal rhythm. It is performed under a general anaesthetic.
• Catheter ablation is a more invasive method that may be used to restore a normal heart rhythm. In this procedure, a catheter (a long, thin tube) is inserted into a vein in the leg or arm and threaded all the way to the heart. Radio wave energy is used to damage the small portion of tissue responsible for the abnormal electrical signals.
• Pacemakers help maintain a normal heart rhythm. They are used for people with AF that has not been effectively treated with less invasive treatments. Before inserting a pacemaker, catheter ablation is used to destroy the atrioventricular (AV) node in the heart. The AV node is a part of the electrical control system of the heart that coordinates the atrial and ventricular chambers. The pacemaker takes over the role of the AV node in maintaining a normal heart rhythm.
• Heart surgery is very rarely required. The most common operation performed is known as the maze procedure, where a number of small incisions are made in the atria (upper chambers) of the heart to create a pattern of scar tissue. The scar tissue (which does not carry electrical currents) prevents the abnormal electrical signals that cause AF from travelling through the heart and causing an abnormal heartbeat.

Atrial fibrillation can’t always be prevented but lifestyle changes can help control the level of AF symptoms you experience. 

• Have enough rest and sleep. Tiredness and fatigue is a common trigger for AF.
• Reduce the amount of alcohol you drink or avoid alcohol. Drinking alcohol can trigger or worsen symptoms because alcohol can affect your heart’s electrical signals.
• Be aware of unhelpful ‘stressors’ in your life and take steps to address these.
• Know how to manage any periods of anxiety.
• Reduce caffeine intake as it can trigger AF symptoms.
• Quit smoking as it can aggravate AF and is also a risk factor for heart attacks and stroke.
• Medications. Talk to your pharmacist or doctor before buying any over the counter medicines, complementary medicines or supplements as some can trigger AF symptoms.
• Exercise. Some exercises can trigger symptoms of AF. Find out more about how to stay safe while exercising with AF (see below). 

The Heart Foundation has more information on adjusting to life with AF.(external link)(external link).

Apps reviewed by Healthify

You may find it useful to look at some Quit smoking apps, Alcohol use apps, Nutrition, exercise and weight management apps, Heart rate apps and Stroke apps.

Stories of people living with atrial fibrillation.

Video: Personal story: living with atrial fibrillation

In this video young dad Sela Alo talks about living with atrial fibrillation and how the diagnosis revealed his larger heart problem of mitral valve regurgitation. This video may take a few moments to load.

(Heart Foundation NZ, 2017)

Video: Personal story: a series of videos

In this series of videos, Nikki talks about her journey with atrial fibrillation. This video may take a few moments to load.

(Heart Foundation NZ, 2018)

Find more personal stories at the Heart Foundation website.(external link)