Atrial Fibrillation

What is atrial fibrillation?   

The normal heartbeat is regular and is controlled by a natural, internal pacemaker (the sinus node) in the heart’s right upper chamber (atrium). The electrical impulse which passes through the heart muscle causes it to beat in a controlled and regular way. This creates the normal regular pulse. In atrial fibrillation (AF), the normal regular heartbeat is replaced by a disorganised, irregular rhythm, which gives rise to an irregular and often fast heartbeat. The pumping action of the heart is affected and as a result blood may not pump as efficiently out of the heart to the rest of the body. AF is generally not life-threatening but it is a serious condition which can lead to complications such as heart failure and an increased risk of blood clots which may cause stroke. 

Atrial fibrillation (AF) is the most common heart arrhythmia, which one in four people over the age of 50 are at risk of developing. In Ireland, 11% of people over the age of 80 have atrial fibrillation. 

Atrial fibrillation is a common heart disorder affecting more than 40,000 people in Ireland aged over 50 years. 


What are the symptoms?  

Many people who have AF have no symptoms and it is discovered on a routine check-up. 

Other people experience symptoms which can include: 

  • Palpitations or fluttering in your chest 
  • Breathlessness 
  • Dizziness or feeling faint 
  • Weakness or increased tiredness 
  • Chest discomfort 

What are the causes of atrial fibrillation? 

Atrial fibrillation is common in people with other heart conditions, such as: 

  • High blood pressure 
  • Heart attack 
  • Coronary artery disease 
  • Abnormal or damaged heart valves 
  • Heart defects you're born with (congenital) 
  • Previous heart surgery 
  • Sick sinus syndrome — improper functioning of the heart's natural pacemaker 
  • An overactive thyroid gland or other metabolic imbalance 
  • Diabetes 
  • Sleep apnoea 
  • Chronic lung disease 
  • Viral infections, like flu 
  • Stress due to pneumonia, surgery, or other illnesses 
  • Some over the counter medications such as cold and cough medications which contain stimulants  
  • Caffeine, tobacco or alcohol 

How is atrial fibrillation diagnosed? 

Atrial fibrillation can be detected by regular pulse checks and will only be diagnosed following a check-up with your doctor. 

If your doctor is concerned you will be referred to a consultant cardiologist with expertise in arrhythmia for further evaluation and testing. This specialist is known as an electrophysiologist. 


The following tests may need to be carried out: 

  • ECG (electrocardiogram): measures the electrical activity of your heart and captures the rate and rhythm in a tracing. This is often the first test you will have, but it only captures information at that specific moment in time, so you may need additional tests. 
  • 24/48 hour ECG monitor: you may be asked to wear a portable ECG monitor for one or two days to record information on your heart’s activity over an extended period of time. This may be because the initial ECG was inconclusive. 
  • Echo (echocardiogram): is an ultrasound scan which looks at the structure of your heart, the muscle, the valves and how it is beating. 
  • Event monitor: is a device that is used over a period of time to record the heart activity when you are experiencing an arrhythmia. Some event monitors are implanted under the skin for several months. 
  • Exercise stress test: takes a recording of your heart rate and rhythm, using an ECG, while you are exercising on a treadmill. Exercise can raise your heart rate which may help show any arrhythmias. 
  • EP study (electrophysiology study): is a procedure used to study the electrical function of the heart, and irregularities in your heart rhythm. It is performed to find out why your heart beats too quickly or too slowly, or why it does not beat in a regular rhythm. It helps identify the location of the abnormal electrical signals in your heart. 
  • Coronary angiogram: is a procedure which examines the coronary arteries in your heart to see if there is any narrowing caused by heart disease. It uses dye and an x-ray to show whether your blood is flowing freely, or if your arteries are narrowed or blocked. It can also show any problems in the chambers of your heart or heart valves. This test is also sometimes called cardiac catheterisation. 

How can I prevent this condition? 

To reduce your risk of atrial fibrillation it is important to live a heart-healthy lifestyle. 


A heart-healthy lifestyle may include: 

  • Eating a heart-healthy diet 
  • Keeping a healthy weight 
  • Increasing your physical activity, to the recommended 30 minutes exercise per day 
  • Avoiding smoking 
  • Limiting or avoiding caffeine and alcohol 
  • Reducing stress - high stress levels can cause heart rhythm problems 
  • Using over-the-counter medications with caution, as some cold and cough medications contain stimulants that may trigger a rapid heartbeat 

What is the treatment for atrial fibrillation? 

Treatment for your atrial fibrillation will depend on what is most appropriate for the patient. 

  • Medication management: medications including “anti-arrhythmic” drugs to control heart rhythm, rate control drugs to control the heart rate, and “anti-coagulants” to prevent clotting. 
  • Chemical cardioversion: this is the use of medication to bring your heart rate back to its normal rhythm. These medicines are given either orally or intravenously (through a drip).
  • Electrical cardioversion: this involves a controlled electrical shock which is delivered to the heart through paddles or patches (electrodes) attached to your chest and connected to a defibrillator. The electrical current passes through the heart muscle and restores the heartbeat to a normal, controlled rhythm. Most cardioversions are performed to treat an irregular heartbeat such as atrial fibrillation, atrial flutter and atrial tachycardia. 
    • This procedure takes approximately 30 minutes to perform. You will not be awake while the procedure is taking place. You should expect to be in the hospital for 2-3 hours prior to the procedure. You will be monitored closely afterwards and usually discharged on the same day, once your condition is stable.   
  • Catheter ablation (electrophysiology study/ablation): this is an invasive procedure used to evaluate the electrical functioning of your heart and to permanently interrupt an abnormal electrical rhythm. The procedure involves wires (catheter electrodes) which are passed through a vein in your groin and are carefully placed at specific positions within your heart to record the electrical activity. You will be sedated for this procedure to make you more comfortable.  
    • This test shows how your heart reacts to extra electrical signals delivered to different areas of your heart.  It gives your Consultant detailed information about the cause of your heart arrhythmia and helps identify the most appropriate treatment for you.   
    • Once the source of the abnormal signal is identified, its pathway is blocked by scar tissue which is created using an electrical energy. This blockage prevents the abnormal electrical signal from traveling and so stops the arrhythmia. The creation of scar tissue to block this abnormal pathway is called ablation. This procedure may be required more than once.