The normal heart beats regularly as it is driven by the heart’s pacemaker, called the sinus node. However, all cells in the heart have the ability to trigger their own heart beat independently of the sinus node. If this occurs, it causes an early (or premature) heartbeat, known as an ectopic, also called an extra beat. As ectopics occur earlier than expected, they can cause the sensation of a brief palpitation, usually a momentary fluttering in the chest, and this is often associated with a feeling of uneasiness or anxiety. Ectopics needn’t cause symptoms at all.
‘Ectopic’ means out of place, in this case implying the extra beat is not only out place in terms of timing but also the location of its origin within the heart. There is usually a short pause after an ectopic, giving the additional sensation of a ‘missed’ beat. In fact, many people who experience ectopics only feel the sensation of missed beats, not the ectopics themselves.
The term ‘palpitation’ is used to describe the sensation of feeling your own heart beating. Some say this feels like a fluttering in the chest, or the heart pounding. Others describe it as feeling like a thud or movement in the chest, which you can feel in your neck or in your ears when lying down.
Palpitations are very common and for most people completely harmless. However, they can be a nuisance and feel very unpleasant at times. They often happen when you have over exerted yourself, for example after vigorous exercise, or when you are feeling particularly anxious or under stress.
The timing of the ectopic influences the symptoms felt. As ectopics occur early, it means the heart’s bottom chambers (the ventricles) have less time to fill with blood than normal and so the amount of blood ejected during the ectopic beat is reduced. However, due to the subsequent short pause after an ectopic, the ventricles then have longer than normal to fill with blood and so the subsequent beat feels more forceful, or stronger, and can sometimes be felt in the neck as well. It is this sensation that is commonly felt by patients and is uncomfortable.
The two most common types of ectopic beats are:
Like most causes of palpitations, ectopic beats are usually harmless and do not mean you have a serious heart condition. They generally require no treatment unless they occur very often or cause severe symptoms.
Palpitations and ectopic beats are usually nothing to worry about. Almost every person will have at least a few ectopics every day but the vast majority will not notice any of them. They can be thought of as a completely normal phenomenon of the heart. However, you are more likely to feel palpitations when the ectopics occur if you are under stress or have had too much caffeine or other stimulants such as alcohol, smoking or recreational drugs. Ectopics causing palpitations are also common when people are ‘hung-over’ or have had too little sleep.
Importantly, they can also occur in certain heart conditions, such as conditions that weaken the heart muscle (known as cardiomyopathy), as well as in people who have suffered heart attacks. Therefore the function of the heart needs to be assessed if people develop frequent ectopics.
Chemical imbalances in the blood can also promote ectopics, such as a low blood potassium levels, which can be caused by certain rare metabolic conditions or when taking certain drugs e.g. diuretics.
You are also more likely to develop palpitations or ectopic beats if you are pregnant, or going through the menopause.
It is very common for the frequency of ectopics to be very erratic – some days or weeks can be terrible and then be followed by long periods without anything. It is often unclear what the triggers are in these situations. It is also very common for people to only notice ectopics at rest rather than when being active or rushing around. The reasons for this are that your heart beat at rest is usually much slower and this allows more time for the ectopics to occur and interrupt the normal heart rhythm. But it also means you are more likely to be conscious of your heart at rest and this is especially the case when first going to bed at night, when there is little else to be aware of than your own heart beat.
If you’re concerned about palpitations, you will need to see your GP or a heart specialist. They may arrange for you to have an electrocardiogram (ECG) and/or 24-hour heart monitor to calculate how many ectopics you are experiencing. If ectopics are seen frequently, performing an echocardiogram (ultrasound scan of the heart) is important to assess heart function and exclude cardiomyopathy (heart muscle weakness). This is particularly important if you have a history of heart problems in young people in your family or if there is a family history of people dying suddenly without obvious explanation. It is also a good idea for you to have routine blood tests to exclude metabolic problems like low potassium and also to ensure the thyroid gland is functioning normally.
A 24hr (or more prolonged) heart monitor can calculate the frequency and total burden of ectopics. More than that, it can determine whether the ectopics arise predominantly from one location in the heart or from several. For example, it is possible that all ectopics occur from a single site in a single chamber, or that they occur in multiple sites from the same chamber, or sometimes from multiple sites and/or multiple chambers.
The presence of ectopics is almost always completely benign and has no influence on length of life or developing other diseases. The most important test to confirm this is echocardiography, or sometimes cardiac MRI scanning, to ensure heart function is normal. If heart function is normal, the prognosis is good and the presence of ectopics is merely a nuisance symptom.
If heart function is impaired, or there is another major structural defect e.g. a significant problem with valve function, then the presence of ectopics is usually a consequence of this defect and needs to be investigated separately.
Importantly, in people with very high burdens of ectopics (and almost always ventricular rather than atrial ectopics), the ectopics themselves can cause the left ventricle (the main pumping chamber) to dilate, or get bigger and in time to create impairment of heart function. To put this into context, the average person will have around 100,000 heart beats/day and people who suffer with symptoms of ectopics tend to experience several hundred to several thousand ectopics per day, or a 0.5 to 1-5% burden. We become concerned about the potential for enlargement of the left ventricle when the burden is >10% and significantly concerned when the burden is >25%. If the ectopics originate from a single site, we usually offer catheter ablation to it to prevent this from happening.
Whether or not you need treatment will depend on the underlying cause of the ectopics and how severe your symptoms are. Avoiding the triggers of palpitations and ectopic beats often helps and this means cutting down or avoiding alcohol and caffeine. It is always a very good idea to completely stop smoking! Reassurance is often all that is required after tests have been performed to exclude an underlying heart problem. It is useful to know that most people will stop noticing or can ignore ectopics or find them less of a problem if sufficient reassurance is given. Some people find regular exercise is helpful in reducing ectopics, particularly if you have been sedentary, or avoiding certain food types.
Reducing stress is usually relevant and important although not always easy to achieve. For this reason, medicines such as beta-blockers or calcium channel blockers may be prescribed to prevent ectopics from happening. It is important you see a specialist if you already have heart disease, your doctor thinks you may have a heart condition or if the ectopics are very frequent or continuous. Sometimes it is appropriate to change the medications you take if they are thought to be causative.
In rare cases, the treatments above are unsuccessful and this occurs most often when people experience extremely high burdens of ectopics i.e. they continuously occur every 2-10 beats. This usually means the cause of the ectopic isn’t stress-related, or temporary, but due to a cell or small group of cells in the heart continuously firing of their own accord. It is known this is often due to an abnormality of how cardiac cells handle calcium and this is why drugs called calcium channel blockers can often be helpful in suppressing these.
The phenomenon of having ectopics every 2nd beat is known as bigeminy, and if every third beat, is called trigeminy. Surprisingly, many people with bigeminy or trigeminy have no symptoms at all and it is unknown why some people feel ectopics and others do not, although being under stress certainly makes them more noticeable.
If medications aren‘t helpful in suppressing very frequent ectopics, and especially if there are continuous runs of ectopics (known as ventricular tachycardia), a procedure called catheter ablation is offered.
Catheter ablation is a technique in which fine wires (catheters) are introduced to the heart via the veins at the top of the leg. The wires can then be used to create a 3D computer model of the inside of the chamber where the ectopics are arising. Information from the electrical signals recorded by the catheter during the ectopic beats helps identify where they originate. The catheter is then advanced to that location and energy delivered to the tip of the catheter causing it to heat up. The heat applied to the tissue causes destruction of this tissue (a very tiny area) and abolishes the ectopic. This is what ablation means.
The success of ablation depends largely on how frequently the ectopics are occurring at the time of ablation. The more frequent, the better the chance of success. Ablation can sometimes be performed when no ectopics or very infrequent ectopics are present through a technique known as Pacemapping, but this usually means the success rate drops significantly. In most cases the success rate of ablation is around 80% of a permanent cure. If ectopics are frequently present at the start of the procedure and are abolished during ablation and do not recur by the end of the procedure, this is usually a very good sign that they will not recur afterwards, although this can still happen in some cases.
The risk of ablation of ectopics is usually very low. The commonest risk is injury to the blood vessels at the top of the leg where the catheters are inserted. This includes bruising or bleeding and rarely a more serious injury where the artery adjacent to the vein is injured and this can sometimes mean treatment with injection or surgery can be required. The risk of vascular injury is about 1%. Rarer risks include perforation of the catheter through the wall of the heart and this can mean blood leaking into the sac around the heart. This may require draining with a drain inserted under the ribs or very rarely surgery. There is also the possibility of damaging the normal wiring of the heart (if the ectopic is located near this area) and if permanent damage is created, then a pacemaker can be required. If the ectopic is located on the left side of the heart, there is a rare risk of causing a stroke by ablating in the left side of the heart’s circulation.
The ablation usually takes around 2 hours and most patients will be able to go home later that day,
Recovery is almost entirely related to recovery of the puncture sites at the top of the leg and this usually takes a few days of rest and usually a week before vigorous exercise can be recommenced.