What is Atrial Fibrillation (AF)?

Contents: - What is Atrial Fibrillation

What is Atrial Fibrillation?

Atrial fibrillation is a rapid, irregular heart rhythm which can develop as the heart ages. Ageing causes the cells within the atria (the top 2 chambers of the heart) to conduct electricity increasingly abnormally. Much like our skin looks different in our 60s, 70s and 80s, the tissue of the heart ages too. Rather than smooth ripples of electricity conducting through tissue, electrical chaos develops in an irregular pattern. This causes the heart to become much less efficient and heart function is reduced.

Rapid, irregular palpitations, breathlessness, chest pain lightheadedness and tiredness

AF can cause rapid, irregular palpitations, breathlessness, chest pain, lightheadedness and tiredness. However, it causes no symptoms at all in about a quarter of patients, and yet their risk of stroke is the same as if symptoms are present. The risk of developing AF increases with increasing age and it is also very frequently seen in patients with high blood pressure or other cardiac problems like heart attacks, valve disease or other heart muscle problems. However, AF can also occur in people with no other medical problems.

AF - The Most Common Heart Rhythm Disorder

Atrial fibrillation is the most common heart rhythm disorder in the developed world and it is estimated that more than one million people in the UK have this condition. Atrial fibrillation, or AF for short, is the 2nd most common cause of stroke in the UK and the most common in the non-elderly population. Overall, it increases the risk of having a stroke by a factor of 5 and can also lead to heart failure in some patients.

Atrial Fibrillation (AF) and risk of stroke

When the electrical activity in the atria becomes chaotic, blood can stagnate inside them and this can cause a clot to form inside the heart, particularly in what is called the left atrial appendage. This is a tube-like chamber (a bit like the appendix in the bowel) attached to the left atrium. When clots form here they can dislodge, travel through the heart and circulation to the brain, where they result in a stroke.

To identify patients who are at risk of stroke when they have atrial fibrillation, we use a scoring system called the CHA2DS2-VASc scoring system.

CHA2DS2VASc score

The CHA2DS2VASc score is an acronym. It stands for:
C         =          Congestive cardiac failure (or heart failure or impaired ventricular function)

H         =          Hypertension (or high blood pressure)

A2        =          Age over75

D         =          Diabetes

S2          =          Stroke or TIA (transient ischaemic attack, or ‘mini-stroke’)

V         =          Vascular disease (heart attack or other arterial disease)

A         =          Age over 65

Sc       =          Sex category (female = 1 point)

If you have or have ever had one of these conditions you score one point for each, except Age over 75 or Stroke/TIA, which each count as 2 points, hence CHA2DS2VASc score.

What your CHA2DS2VAScscore means

If you have a CHA2DS2VASC score of 1 or more, it is recommended you take warfarin (or one of the newer types of anticoagulant medications, the NOACs) for the rest of your life to reduce your risk of stroke. So, if you are 65 or older and are diagnosed with atrial fibrillation, it is recommended you are treated with an anticoagulant and not aspirin, which is now known to have no benefit.

The only exception to this rule is if your only CHADS-VASc point is due to female gender. We know women are at slightly higher risk of stroke than men if they have AF but this only becomes relevant if women are over 65 years old or if they already score another point on the CHADS-VASc scoring system. In other words, if you are a 64 year old woman and have no other medical problems, you still score 1 point but do not need an anticoagulant. However, once you turn 65, you will need an anticoagulant and you will score 2 points.

How can Atrial Fibrillation be Diagnosed and Identified?

If you develop any of the symptoms described above, a simple check of your pulse can confirm if it is beating irregularly. To diagnose AF, an electrocardiogram (ECG or heart tracing) is needed when you feel palpitations or other symptoms. If your symptoms are intermittent, you may need to wear a heart monitor for a longer period of time to try and capture an episode.

Atrial fibrillation can also be easily identified in patients with pacemakers or defibrillators when their device is checked.

Occasionally it is necessary to implant a small heart monitor under the skin to diagnose a patient’s palpitations, if they are very infrequent or if you have had a stroke which is thought could have been due to undiagnosed AF.

ECG of atrial fibrillation – irregular and rapid, chaotic atrial activity seen under lead V1 (the wiggly line!)

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About Dr Oliver Segal MD FRCP FHRS

  • Qualified from King’s College Hospital in 1995
  • Trained at St. Bartholomew’s, London Chest, St. Mary’s and St George’s Hospitals in London in cardiology and electrophysiology. Awarded a fellowship in pacing and electrophysiology at the world-renowned unit of electrophysiology in London, Ontario, Canada in 2007 with Prof. George Klein.
  • Won first prize for Clinical research for his work on mapping ventricular tachycardia at the Heart Rhythm Society Young Investigator Award in San Francisco, USA in 2004.
  • Appointed as full time Consultant Electrophysiologist at The Heart Hospital, University College London Hospitals in 2008. He is also Honorary Consultant at Homerton Hospital, Queen Elizabeth the Queen Mother Hospital, Margate and the Great Ormond Street Hospital.
  • Has admitting rights at The Harley Street Clinic, Wellington Hospital, London Bridge Hospital, BUPA Cromwell Hospital and St. Anthony’s Hospital Cheam
  • Has over 10 years experience in electrophysiology and devices, and has performed more than1500 ablation procedures and over 850 device implantation procedures

Dr Oliver Segal's Personal Philosophy

“Patients deserve the best quality healthcare provided by highly trained professionals. I am proud to be able to offer the state of the art in treatment for arrhythmiapatients at some of the UK’s leading private and NHS Hospitals.”

An abbreviation for atrial fibrillation Full medical glossary
A medication that prevens blood from clotting, or which reduces the likelihood of the blood to clot. Full medical glossary
Any form of disturbance to the heart's normal regular beat Full medical glossary
One of the most used medicines. Full medical glossary
The two upper chambers of the heart. Full medical glossary
A common abnormal heart rhythm causing a rapid, irregular pulse and failure of the upper chambers of the heart (atria) to pump properly. Abbreviated to AF. Full medical glossary
One of the two upper chambers of the heart. Full medical glossary
A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
The pressure of blood within the arteries. Full medical glossary
A common name for the large and/or small intestines. Full medical glossary
Relating to the heart Full medical glossary
A tube used either to drain fluid from the body or to introduce fluid into the body. Full medical glossary
The basic unit of all living organisms. Full medical glossary
Blood that has coagulated, that is, has moved from a liquid to a solid state. Full medical glossary
A condition that is linked to, or is a consequence of, another disease or procedure. Full medical glossary
A device used for defibrillation, which involves giving a controlled electric shock to restore normal heart rhythm in cases of cardiac arrest. Full medical glossary
Devices used for defibrillation, which involves giving a controlled electric shock to restore normal heart rhythm in cases of cardiac arrest. Full medical glossary
The abbreviation for electrocardiogram, a tracing of the electrical activity of the heart to help in the diagnosis of heart disease. Full medical glossary
A tracing of the electrical activity of the heart. Full medical glossary
Abnormally fast and uneven contractions of the heart muscle, so that blood cannot be pumped efficiently Full medical glossary
The death of a section of heart muscle caused by an interruption in its blood supply. Also called a myocardial infarction. Full medical glossary
Failure of the heart to pump adequately. Full medical glossary
Stopping or ceasing for a time. Full medical glossary
A large abdominal organ that has many important roles including the production of bile and clotting factors, detoxification, and the metabolism of proteins, carbohydrates and fats. Full medical glossary
Tissue made up of cells that can contract to bring about movement. Full medical glossary
osteoarthritis Full medical glossary
A small electrical device that functions to maintain a normal heart rate. Full medical glossary
The feeling when you become aware of your heartbeat - when frightened, for example. Full medical glossary
septic arthritis Full medical glossary
Any sudden neurological problem caused by a bleed or a clot in a blood vessel. Full medical glossary
An abnormally fast heart rate of over 100 beats per minute Full medical glossary
Transient ischaemic attack; a brief interruption of the blood supply to part of the brain, which causes temporary impairment of vision, speech, sensation or movement.. Full medical glossary
A group of cells with a similar structure and a specialised function. Full medical glossary
Any neurological problem caused by an interruption in the blood supply to the brain that resolves within 24 hours. Abbreviated to TIA. Full medical glossary
A structure that allows fluid to flow in one direction only, preventing backflow. Full medical glossary
Relating to a ventricle (either in the brain or the heart) Full medical glossary
An anti-coagulant drug used to treat and prevent abnormal blood clotting. Full medical glossary