“AF can be tricky to understand, this section will provide you with the information you need to help you understand your condition, I hope you find it useful”Dr Matthew Fay - General Practitioner Principal, Westcliffe Medical Centre, West Yorkshire

What is AF-related stroke?

AF is a heart condition - more specifically a type of irregular heartbeat. It means your heart is not working as well as it should be and, if left unmanaged, may make you more likely to have a AF-related stroke.

Your heart is a muscle and its job is to pump blood around the body - this pumping action creates your pulse. Normally, your heart's natural pacemaker sends out regular electrical impulses. A normal pulse (when resting) is regular and between 60 to 100 beats a minute.

AF happens when other electrical impulses fire off independently from the natural pacemaker from different places in the atria (the top chambers of the heart) in a disorganised way. If you have AF, your heart beats faster and in an irregular way - sometimes more than 140 times a minute.

For many people AF is associated with a risk of AF-related stroke, caused by blood clots forming in the heart and then travelling in the bloodstream to the brain. The blood clots can block the blood flow to part of your brain causing an AF-related stroke or mini-stroke (sometimes referred to as a transient ischaemic attack or TIA).

AF can come and go without warning (known as paroxysmal AF). There could be long spells between 'episodes'. As many as half of all patients may not even be aware they have it. AF falls into three categories.

The risk of having a stroke is increased with all types of AF so protecting against this is the most important consideration. There are other management options which will be discussed later on.

The three types of AF are:

  • Paroxysmal AF - multiple episodes that stop within seven days without treatment
  • Persistent AF - episodes that last longer than seven days, or less when treated
  • Long standing persistent AF - continuous AF which may not be suitable for treatment. You may also hear this referred to as permanent or sustained AF.

AF can be more frequent in people with other forms of heart disease, most commonly high blood pressure. Various other heart problems may also trigger AF to develop, but having AF does not mean that the patient has other forms of heart disease.

Who is affected?

AF is the most common heart rhythm disturbance encountered by doctors. NHS 2011 figures suggest AF affects in excess of one million people across the UK, although this is considered to be an underestimation due to delayed detection and diagnosis.1

It can affect adults of any age, but it is more common as people get older. In the over 65 age group, it affects about 10 per cent of people.1

What are the causes and symptoms?

The causes of AF are not completely understood, but it is age related – the older you become the more likely you are to develop it. However, it is more likely to occur in patients who have other heart conditions, such as:

  • High blood pressure
  • Heart disease (coronary artery disease)
  • Mitral valve disease (caused by rheumatic heart disease, valve problems at birth or infection)
  • Congenital heart disease (abnormality of the heart present since birth)

Other conditions and situations that may trigger AF to develop include: alcohol consumption, an overactive thyroid, pneumonia, pulmonary embolism.

Many people with AF have no symptoms and it is only discovered during a routine medical examination or after a health problem. However, for those who do, the most common symptoms include:

  • Palpitations or awareness of the heartbeat which may be beating very fast
  • Tiredness
  • Shortness of breath
  • Dizziness
  • Chest pain

What are the possible complications of AF?

The main complication of AF is an increased risk of having a stroke. Every 15 seconds someone suffers an AF-related stroke.2

AF can cause turbulent blood flow in the heart chambers, sometimes leading to a small blood clot forming. A clot can travel in the blood vessels until it gets stuck in a smaller blood vessel in the brain (or sometimes in another part of the body). As a result part of the blood supply to the brain can be cut off and this is what causes an AF-related stroke.

Less common complications of AF include:

  • Heart failure - This can develop if the heart becomes weak, as a result of the rapid rhythm caused by AF. As the heart weakens, blood flows back into the lungs and affects the normal breathing pattern.3 AF can also cause heart failure even in patients who have well controlled heart rates, although this is very rare.
  • Angina (chest pains / discomfort) - AF can cause angina to occur or become more frequent.

AF is also associated with a slightly increased risk of death although generally it is not considered a life threatening disease in its own right. Why AF is associated with increased risk of death is not fully understood.3

1. The Atrial Fibrillation Association, Patient Information Atrial Fibrillation. Available from: http://www.atrialfibrillation.org.uk/patient-information/atrial-fibrillation.html. Accessed April 2014

2. The Atrial Fibrillation Association, Patient Information Stroke. Available from: http://www.atrialfibrillation.org.uk/patient-information/stroke.html. Accessed April 2014

3. The Atrial Fibrillation Association, Patient Information Risks. Available from: http://www.atrialfibrillation.org.uk/patient-information/risks-atrial-fibrillation.html. Accessed April 2014