Atrial fibrillation

Read personal stories from myheart members with atrial fibrillation.

Watch CRY Patron Tom James MBE talk with Professor Sharma about his experience of finding out and living with atrial fibrillation.

What is atrial fibrillation?

Atrial fibrillation (AF) is the most common heart rhythm disorder. It affects around 1-2% of the overall population. It is more common in men and is increasingly common as people age [1]. While it is associated with other medical conditions such as high blood pressure, obesity and other types of heart disease [2], people who are otherwise fit and healthy may still develop AF.

AF occurs when the electrical signals in the heart’s upper chambers, the atria, become chaotic and disordered, overriding the heart’s natural pacemaker. This causes the heart to beat irregularly. The heart rate is highly variable and can beat very fast and in turn very slowly. This irregularity affects the efficiency of the heart and can reduce the amount of blood it is able to pump around the body [3].

Early in the condition, AF will occur for a short period before the heart corrects itself and returns to a normal rhythm (this is known as paroxysmal AF [4]). Left untreated, these episodes last longer and it becomes more difficult to restore the heart’s normal rhythm before eventually the heart rhythm remains irregular (i.e. in AF) permanently [5].

What symptoms does AF cause?

The symptoms of AF vary between people, and many people are not aware of any symptoms at all. The most common symptom is palpitations. They may be associated with chest pain, light-headedness, breathlessness and fatigue [2]. They may start suddenly and last for a few minutes to several hours. Often there is no pattern to when the palpitations occur but there may be particular triggers for some people. These too are variable and include exercise, emotional stress and alcohol [4].

As AF becomes chronic and long-standing sudden palpitations become less common. When the symptoms are less obvious, people may complain from breathlessness, a lack of energy or fluid retention [2].

How is AF diagnosed?

AF causes an irregular pulse that can often easily be felt at the wrist. In asymptomatic individuals, this may be the only sign of the condition and finding an irregular pulse should always raise the suspicion of AF [4]. Formal diagnosis requires an ECG that shows the chaotic electrical activity and irregular heart rhythm. Several ECGs or a prolonged recording may be needed for people with paroxysmal AF since the ECG is frequently normal between episodes [4].

In addition, other tests may be required to look for associated conditions. These may include an echocardiogram to look at the structure and function of the heart or a prolonged ECG to monitor the variation in heart rates during the day and night.

What are the risks of AF?

Although the symptoms of an episode of AF can be very unpleasant, an acute episode is not life threatening and can often be managed at home with an appropriate support and treatment plan.

The most important potential risk of AF is having a stroke [6]. A person’s risk of suffering a stroke is 5 times higher if they have AF [4] because blood flowing through the heart’s upper chambers (the atria) can slow, allowing small blood clots to form, particularly in the left atrium. These blood clots have the potential to break off and travel through the bloodstream blocking blood vessels in other organs such as the brain, where they can lead to a stroke. The risk of an individual with AF having a stroke is not related to the number of episodes of AF they have, but to the presence of other conditions that can independently increase the risk of having a stroke. These include heart failure, high blood pressure, diabetes, arterial disease (such as coronary artery disease or peripheral vascular disease) having had a previous stroke, and increasing age [4]. Females are also at a slightly higher risk of stroke than males as they get older [7].

AF can also lead to memory problems and cognitive decline [8] and is a common cause of hospital admissions [7].

How is AF treated?

Like many things related to AF, the treatment options are varied and complex and should be tailored specifically to the individual. There are three broad focuses of treatment: prevention of stroke; maintaining the heart’s normal rhythm; and preventing the heart beating too fast when in AF.

Stroke prevention is the mainstay of treatment in AF. For the vast majority of patients this is done by means of thinning the blood with medications known as anticoagulants so that clots cannot form. Traditionally warfarin has been the only effective drug and is still used widely today. However, there are now several other anti-coagulant drugs that are useful in AF [8]. The decision over which one is right should be discussed between the patient and their doctor. Aspirin is not recommended for stroke prevention in people who have AF [4].

For those people who cannot take anticoagulant medications, a device can be implanted in the left atrium of the heart to prevent blood clots breaking off and entering the bloodstream [9].

Keeping the heart in its normal rhythm and preventing the recurrence of AF is another important goal of the treatment of AF. Medications called antiarrhythmics can be used to help achieve this. There are many available and each has particular benefits and considerations to take into account. Commonly prescribed antiarrhythmics in the UK include flecainide, sotalol, dronedarone and amiodarone [10].

Another option for the prevention of AF recurrence is an ablation procedure. Ablation of AF aims to prevent the disordered electrical signals seen in the atria during AF. Wires called catheters are introduced into the left atrium of the heart via the femoral vein at the top of the leg. Once in the left atrium, these catheters are used to cauterise specific areas of heart tissue to prevent the abnormal conduction of electrical signals. Ablation is an effective treatment for preventing AF in the short and medium term and although it does not offer a permanent cure it can reduce the need to take antiarrhythmic medication [11].

When an episode of AF occurs, normal rhythm can be restored with a procedure called a cardioversion [4]. This involves giving a controlled electrical shock to the heart while the patient is under conscious sedation or anaesthesia. The shock stuns the electrical tissue of the heart and allows the natural pacemaker to restore the normal heart rhythm. Intravenous medication can also be used instead of or in conjunction with the electric shock.

Since it is very difficult to get rid of AF permanently, an alternative treatment option is to prevent the heart beating very fast when AF occurs. This is because it is when the heart beats very fast that most symptoms occur. The most commonly used family of drugs for this are beta-blockers although others such as calcium channel blockers and digoxin may also be used [4][10]. For those individuals who have AF with slow heart rates, an electronic permanent pacemaker can be used to prevent the heart beating too slowly.

The treatment of any individual with AF will be spefically tailored to their particular situation, depending on their symptoms, type of AF, and other medical history but will involve a combination of the strategies discussed above .

AF in young people

While AF is more common in older people, it can affect young people in the absence of any other heart problems. In this situation there may be an underlying genetic cause such as a problem with a sodium channel in the heart. These sodium channels are important for determining the electrical properties of the heart and problems can lead to a number of heart rhythm problems including AF.

The treatment of AF in young people is similar to that described above. In general the risk of stroke in young people is lower so there is less need for anticoagulant medications [8]. In addition, ablation may be recommended more commonly as the initial treatment in young people with otherwise normal hearts as it has been shown to be as effective as antiarrhythmic medication in such patients [12].

AF in pregnancy

A first episode of AF during pregnancy is rare in women without previously known heart problems. Around 50% of pregnant women who have pre-existing AF have an episode during their pregnancy [3].

Many of the drugs commonly used for the treatment of AF have potential problems in pregnancy: beta-blocker drugs may cause reduced growth of the foetus. Alternatives such as verapamil and diltiazem are generally safe. Amiodarone can cause harm to the foetus and should only be used in emergencies. Electrical cardioversion has been used safely in pregnant women. Regarding anticoagulants, warfarin is known to harm the foetus and should be avoided. The newer anticoagulant medications are also not recommended. Daily injections of low-molecular weight heparin (LMWH) can be used in their place at much lower risk [4].

AF in athletes

AF has been shown to occur more frequently in men who participate in prolonged strenuous exercise such as endurance sports [13][14]. This is most likely due to the structural and functional changes seen in the heart in response to prolonged exercise.
Treatment options are often slightly different since beta-blocker drugs are not well-tolerated in athletes and other drugs may not be potent enough to treat the fast heart rates that can occur with exercise-induced AF. Therefore ablation therapy may be considered earlier. Individuals taking anticoagulant medications cannot participate in contact sports due to the risk of bleeding [4].

Watch CRY myheart cardiologist Dr Michael Papadakis talk about why people with ICD are not allowed to play contact sports.

Please click here for references to text

Andy Perry

Living with hypertrophic cardiomyopathy

My name is Andy. I’m now 38 and at the tender age of 7 after dental treatment, I was ill and taken to the local hospital. After several tests they diagnosed me with a heart murmur.

Several years later, attending senior school aged 11, I was taken ill doing sports. My mother went along with me to my GP who sent me to hospital via ambulance. I was admitted for tests – I had an ECG (electrocardiograph) and chest X-rays, and they noticed a vast difference in the size of my heart compared to when I was 7.

I was referred to a paediatric cardiologist whom performed a cardio catheter and diagnosed me with hypertrophic obstructive cardiomyopathy (HCM). At that time very little was known about this condition. My mum was called into the side room with the doctor – she was alone as dad was at work – and she was told that I wouldn’t see my 20th birthday.

I lived with the condition, but you can imagine that at eleven years old I wanted to do normal eleven-year-old things – i.e. running, playing with mates, etc – but Mum didn’t let me. I went for regular treatment and check ups and took tablets every day. Mum basically wrapped me up in cotton wool and made me tread on egg shells.

There were numerous times I was admitted to hospital for the next 15 years. During these years not much could be done, as little was known about the condition. Then, aged 26, I was very poorly with atrial fibrillation and had to be cardioverted 5 times in one year. I was told that I had to have an ablation of my atrioventricular node and be paced – which helped me a lot.

I still had frequent hospital stays and check ups. At 30, I met my now wife and we have 3 children. I now know why mum treated me with such close care and love, as my own children are now under close medical supervision. As yet my children are clear.

If it wasn’t for Mum I would certainly have died at a young age. She was so strong through this and now my wonderful wife, Becky is my guardian angel, as Mum is now disabled – but still there for me and my wife. Mum has remarried to a wonderful man who looks after her – and he has done more than his share of caring for me at times of illness before I met my wife.

On December 3rd 2007, I was admitted to hospital to get my pacemaker changed. This procedure was successful.

Cardioversion

A cardioversion is a procedure that can help your heart rhythm get back to its normal, sinus rhythm if it is in a persistently abnormal rhythm (such as atrial fibrillation or atrial flutter).

Before your cardioversion takes place, you will be given a general anaesthetic so that you will be asleep during it. Because of this, you will usually have to be starved for a minimum of 6 hours prior to the procedure.

Large stickers (called ‘pads’) will be placed on your chest, and these are in turn connected to a defibrillator. Over the course of about 10 minutes, you may be given up to three electrical shocks from the defibrillator. The shock(s) should put your heart back into a normal rhythm, after which you are woken up again. In some instances, the shocks cannot restore sinus rhythm – if this is the case, you will just be woken up again and another attempt may be made on another day.

You may feel slightly sleepy and sick after your general anaesthetic, and you may have some irritation on your chest where the shock was given (although this is rare).

Implantable cardioverter defibrillator (ICD)

Read the ICD Special Issue myheart newsletter

If the bottom chambers (ventricles) of your heart are prone to going into either a dangerously fast or a chaotic heart rhythm (called ventricular tachycardia and ventricular fibrillation respectively), or if you are thought to be at risk of your heart going into these dangerous rhythms, then an implantable cardioverter defibrillator (ICD) can help you.

An ICD is a small device that is about the size of a matchbox. It is implanted under the skin below the collar bone, usually on the left hand side. One or more wires run from the ICD to the heart. The ICD is able to monitor your heart rhythm at all times; if it notices that your heart is going into an abnormal rhythm, it returns it to normal in one of three ways:

1.     Antitachycardia pacing (ATP) – fast, low-voltage impulses try to override an   abnormally fast heart rhythm (usually ventricular tachycardia), momentarily taking over control of the heart, with the aim of restoring it back into a normal rhythm.

2.     Cardioversion – small electric shocks return the heart to its normal rhythm.

3.     Defibrillation – bigger electric shocks put the heart back into a normal rhythm

When you have your ICD fitted, you will usually be sedated. This means that you will feel very relaxed and sleepy, and as a result people often remember nothing or very little of the procedure. You will also have a local anaesthetic so that you do not feel any pain where the ICD is inserted. Most people stay in hospital the night after their ICD is fitted. Before you leave, some tests will be performed to check that it is working as it should be.

Watch myheart member, Joseph Tanner, talk about his experience of having an ICD implanted.

Watch CRY myheart cardiologist, Dr Michael Papadakis, talk about the limitations of ICD below.

ICD and Contact Sports

Watch CRY myheart cardiologist’s video on getting the settings of an ICD right for an individual who does intensive exercise here.

Watch CRY myheart cardiologist’s video on why you wouldn’t be allowed to play contact sports if you have been fitted with an ICD below.

Hypertrophic cardiomyopathy (HCM)

Read personal stories from myheart members with hypertrophic cardiomyopathy here.

Hypertrophic cardiomyopathy (HCM) is a condition where the heart muscle becomes thickened.

Traditionally, the term HCM was used for disease caused by abnormalities in genes which make the proteins responsible for contraction of the heart (sarcomeric contractile proteins). More recently the definition of HCM has been broadened to include a number of other conditions that result in thickened heart muscle. It is a hereditary disease i.e. it is passed on from parents. In the majority of cases the condition is inherited from a defective gene of one of the parents in such a way, that if a parent has an abnormal gene then each child has a 50% chance of inheriting the disease.

It is a disease that can affect both men and women of any ethnic origin. The condition is present from conception and excessive growth of the muscle may begin before birth when the foetal heart is developing. In a healthy adult heart, the muscle fibres are arranged in an organised fashion and their thickness does not exceed 12mm. In the HCM heart, however, the muscle becomes excessively thick and the fibres are arranged haphazardly making the heart vulnerable to some dangerous heart rhythms (ventricular fibrillation or ventricular tachycardia). The heart muscle also may thicken in individuals who have high blood pressure or who participate in prolonged athletic training, but in HCM patients the muscle thickens without an obvious cause.

What are the symptoms?

Symptoms and severity can vary from person to person.  They may begin in infancy, childhood, middle or elderly life.  No particular symptom or complaint is unique to HCM sufferers.  Most patients never experience any symptoms, thus affected individuals are often diagnosed during ECG screening or family screening.

The most common symptoms of HCM are:

shortness of breath
chest pains (usually brought on by physical exertion)
palpitations (rapid, irregular heart beat)
light-headedness, blackouts.

If you suffer from any of these symptoms it does not mean that you necessarily have HCM but if you visit your GP, he or she may suggest that you undertake some tests or may refer you to a cardiologist (a heart specialist).

How is it diagnosed?

Diagnosis involves having an ECG and an ultrasound scan of the heart (echocardiogram). The great majority (up to 98%) of individuals with HCM have an abnormal ECG, alerting the physician to the possibility of underlying heart disease. Although the echocardiogram is the gold standard test in the diagnosis of this condition, occasionally the ECG may become abnormal long before the excessive thickening of the heart can be observed in the echocardiogram. In individuals with a diagnosis of HCM or high index of suspicion, further tests with an exercise treadmill test and a 24-Holter is required. In some cases further imaging of the heart may be necessary using a magnetic resonance imaging scan (MRI).

Genetic testing can identify carriers of the HCM gene. Unfortunately, this form of testing is limited at the moment, as 3 in every 10 people who are known to have HCM do not have mutations of the genes known to be associated with HCM. An additional problem is that many families who do have the mutations appear to have a specific change to the DNA code which is not found in other families (known as a ‘private’ mutation). This sometimes makes it difficult to decide whether a mutation is causing the disease or not. Things are further complicated because people with the same mutation can have effects of varying severity. However, when a well known HCM gene is identified, it can be used after the clinical evaluation to confirm the diagnosis or in the context of family screening

Treatment and advice

There is no cure at present for HCM. Treatment is aimed at preventing complications and improving symptoms. Treatment can be obtained through lifestyle modification advice, drugs, specialised pacemakers, or in some cases, surgery.

If your tests prove positive your specialist will advise you on lifestyle modifications. You will probably be advised not to participate in competitive sport and strenuous activities.

Watch CRY’s myheart cardiologist, Dr Michael Papadakis talk about things to avoid with cardiomyopathy below.

For many people the condition should not significantly interfere with their lifestyle and can be controlled by drugs. Drugs are given initially when a patient presents with symptoms. A variety of drugs are used in the treatment of HCM and the choice of treatment will vary from patient to patient. However, in patients with severe symptoms, who do not respond to medical treatment, surgery may be suggested. A surgical myomectomy, where muscle is removed, is usually successful in the relief of symptoms. The operation involves removing a portion of the thickened muscle, which relieves the obstruction.

There are other forms of treatment, which are occasionally recommended for people with HCM.

  • Electrical cardioversion– This is for sufferers of atrial fibrillation (irregular heart beat), which is quite common in HCM patients.  It is carried out under general anaesthetic and involves the patient being given a small electric shock to the chest which restores the normal heartbeat.
  • Pacemaker– In HCM sufferers the normal electric signal may fail, and if so a pacemaker can be fitted.  This is a small box containing a battery which is placed in the chest under the skin and ensures the heart receives the necessary electrical signals.
  • Implantable cardiac defibrillator (ICD) – In cases where a rapid heart beat is seen that could potentially cause cardiac arrest, and cannot be controlled by drugs, an ICD may be fitted. This is similar to a pacemaker where a box is implanted under the skin in the chest. The box has a fine wire which is attached to the heart to record and deliver electrical impulses in the presence of an abnormal heart rhythm.

What should you do if you are diagnosed with HCM?

If your tests prove positive your specialist will advise you on lifestyle modifications.  You will probably be advised not to participate in continuous strenuous activities e.g. competitive sports.  For many people the condition should not significantly interfere with their lifestyle and can be controlled by drugs.  It will be necessary for you to have at least annual check-ups.  However, the severity of the disease varies from person to person and even if you have been diagnosed with HCM you may not necessarily present any symptoms and can live a fairly normal life.  Since the disease runs in families, all first degree relatives of the affected patients have to be screened with ECG and an echocardiogram.