Atrial fibrillation (AF) is a heart condition that causes an irregular heart rhythm.
A normal heart rhythm should be regular and between 60 and 100 beats a minute when you're resting.
You can measure your heart rate by checking your pulse in your wrist or neck.
Symptoms of atrial fibrillation
In atrial fibrillation, your heart rhythm is irregular and can sometimes be very fast. In some cases, it can be much higher than 100 beats a minute.
This can cause problems including dizziness, tiredness and shortness of breath.
You may be aware of heart palpitations. This is where your heart feels like it's pounding, fluttering or beating irregularly. This can last for a few seconds or minutes. In some cases, it can last for years (chronic).
Atrial fibrillation often does not cause any symptoms. You may have it and be unaware that your heart rate is irregular.
Symptoms of atrial fibrillation
Causes of atrial fibrillation
Every time the heart beats, its walls tighten and contract to force blood out and around the body. Then the walls relax so the heart can fill with blood again.
In atrial fibrillation, the heart's upper chambers (atria) contract randomly. Sometimes they contract so fast that the heart muscle cannot relax between contractions. This reduces the heart's ability to pump blood around the body.
It can cause you to feel tired and short of breath. It can also lead to the heart forming clots.
Atrial fibrillation happens when abnormal electrical impulses suddenly start firing in the atria. These impulses override the heart's natural pacemaker. This means it can no longer control the rhythm of the heart, causing it to beat randomly.
The cause is not fully understood.
Who is affected by atrial fibrillation
Atrial fibrillation is the most common heart rhythm disturbance in Ireland.
It can affect adults of any age, but it's more common in older people.
Atrial fibrillation is more likely to happen in people with other conditions, such as:
- high blood pressure
- obesity
- other heart issues
- thyroid conditions
It may be triggered by certain situations, such as drinking too much alcohol, drug use or strenuous exercise.
Types of atrial fibrillation
There are 3 types of atrial fibrillation. All of these can carry a risk of stroke.
Paroxysmal AF
Episodes usually last for hours or days. The episodes come and go on their own, and do not usually last longer than 1 week.
Persistent AF
Episodes last longer than 1 week and do not go away on their own. You will need medical treatment to bring back your normal regular rhythm.
Permanent AF
Permanent AF is when your irregular heartbeat does not return to its normal rhythm, even with medical treatment.
Treating atrial fibrillation
Atrial fibrillation is not usually life threatening but it can lead to a stroke. It can be uncomfortable and often needs treatment.
Treatment may involve:
- medicines to prevent a stroke
- medicines to control the heart rate or rhythm
- cardioversion - the heart is given a controlled electric shock to restore normal rhythm
- catheter ablation - where a keyhole procedure is used to treat the area inside the heart that's causing the abnormal heart rhythm
If you have a catheter ablation you may then need to have a pacemaker fitted to help your heart beat regularly.