PALPITATIONS - a patient's guide
What are palpitations?
Palpitations are an awareness of your own heartbeat, usually because the heartbeat seems irregular, or unusually rapid, or in some other way "different" to normal. An abnormal heart rhythm is referred to as an arrhythmia.
Normally, of course, you are not aware of your heart beating at all. The heart beats in response to an electrical stimulus (a bit like the way a car engine fires in response to a spark from a spark plug), and palpitations usually stem from a problem in this electrical system that generates the heartbeat. The heart muscle can continue to contract effectively even if the electrical system is "misfiring" from time to time.
The first thing to emphasise about palpitations is that they usually do not mean that you have a significant heart problem, and in many cases do not even require treatment, although just occasionally they can be an indicator of a potentially serious condition. Even if treatment is required, the cure may be quite simple, such as avoiding caffeine (coffee, tea, coca cola), avoiding drugs which can make the heart race e.g. decongestants and cold cures, or avoiding excessive alcohol use.
Types of palpitation
People may describe their palpitations in lots of different ways, but there are some common patterns:
The heart "stops"
You may have the feeling that your heart stops beating for a moment, and then starts again with a "thump" or a "bang". Usually this feeling is caused by an extra beat (premature beat or extrasystole) that happens earlier than the next normal beat, and results in a pause until the next normal beat comes through. People are not usually aware of the early, extra beat, but may be aware of the pause, which follows it (the heart seems to stop). The beat after the pause is more forceful than normal, giving the "thumping" sensation.
The heart is "fluttering" in the chest
Any rapid heartbeat (or tachycardia) can give rise to this feeling. A rapid, regular fluttering in the chest may be associated with sensation of pounding in the neck as well, due to simultaneous contraction of the upper, priming chambers of the heart (the atria) and the lower, main pumping chambers (the ventricles). If the fluttering in the chest feels very irregular, then it is likely that the underlying rhythm is atrial fibrillation (see item on atrial fibrillation). During this type of rhythm abnormality, the atria beat so rapidly and irregularly that they seem to be quivering, rather than contracting. The ventricles are activated more rapidly than normal (tachycardia) and in a very irregular pattern.
When do palpitations occur?
Palpitations may be associated with feelings of anxiety or panic; it is normal to feel the heart thumping when you are terrified of something, but it may be difficult sometimes for people to know which came first, the palpitations or the panic feeling. Unfortunately, since it can take some time before a clear diagnosis is made in a patient complaining of palpitations, people are sometimes told initially that the problem is anxiety.
Stressful situations cause an increase in the level of stress hormones, such as adrenaline, circulating in the blood, and there are some types of abnormal heart rhythm that can be stimulated by adrenaline excess, or by exercise. It may be possible to diagnose these sorts of palpitations by performing simple tests, such as an exercise test, while monitoring the ECG.
Some types of abnormal heart rhythm seem to be affected by posture, and you may notice that standing up straight after bending over provokes a rapid heart rate. Often these attacks can be abolished again by lying down. Many people, if not all of us, are more aware of the heartbeat when lying quietly in bed at night. This is partly because our attention is not focussed on other things, but also because the slower heart beat at rest can allow more premature beats to occur.
Often you may not be aware of anything apart from the abnormal heart rhythm itself, but palpitations can be associated with other things such as tightness in the chest, shortness of breath, dizziness or light-headedness. Depending on the type of rhythm problem, these symptoms may be just momentary or more prolonged. Actual blackouts or near blackouts, associated with palpitations, should be taken seriously because they often indicate the presence of important underlying heart disease.
How is a diagnosis made?
The most important initial clue to the diagnosis is your description of the palpitations. Your age (approximately) when you first noticed them, and the circumstances under which they occur are important, as is information about caffeine intake (don't forget tea and coca cola, as well as coffee). It is also very helpful to know how they start and stop (abruptly or not), whether or not they are regular, and approximately how fast the pulse rate is during an attack. If you have discovered a way of stopping the palpitations, that is also helpful information.
The diagnosis is usually not made by a routine medical examination and electrical tracing of the heart's activity (ECG), because most people can not arrange to have their symptoms while visiting the doctor! Nevertheless, findings such as a heart murmur or an abnormality of the ECG, which could point to the probable diagnosis, may be discovered. In particular, ECG changes that can be associated with specific disturbances of the heart rhythm may be picked up; so routine physical examination and ECG remain important in the assessment of palpitations.
Blood tests, particularly tests of thyroid gland function, are also important baseline investigations (an overactive thyroid gland is a potential cause for palpitations; the treatment in that case is to treat the thyroid gland overactivity).
The next level of diagnostic testing is usually 24 (or longer) ECG monitoring, using a form of tape recorder (a bit like a Walkman), which can record the ECG continuously during a 24-hour period. If symptoms occur during monitoring it is a simple matter to examine the ECG recording and see what the cardiac rhythm was at the time. For this type of monitoring to be helpful, the symptoms must be occurring at least once a day. If they are less frequent then the chances of detecting anything with continuous 24, or even 48-hour monitoring, are quite remote.
Other forms of monitoring are available, and these can be useful when symptoms are infrequent. A continuous-loop event recorder monitors the ECG continuously, but only saves the data when the wearer activates it. Once activated, it will save the ECG data for a period of time before the activation and for a period of time afterwards - the cardiologist who is investigating the palpitations can programme the length of these periods. A new type of continuous-loop recorder has been developed recently that may be helpful in people with very infrequent, but disabling symptoms. This recorder is implanted under the skin on the front of the chest, like a pacemaker. It can be programmed and the data examined using an external device that communicates with it by means of a radio signal.
Investigation of heart structure can also be important. The heart in most people with palpitations is completely in its physical structure, but occasionally abnormalities such as valve problems may be present. Usually, but not always, the cardiologist will be able to detect a murmur in such cases, and an echo scan of the heart (echocardiogram) will often be performed to document the heart's structure. This is a painless test performed using sound waves, and is virtually identical to the scanning done in pregnancy to look at the fetus.
What treatment is required?
The answer to this question really depends on the nature of the problem. In many, if not most people, no specific treatment is required other than avoidance of excessive caffeine intake, or other triggers. For some patients medication may be advised to try to prevent attacks.
There are a variety of medications with effects on the rhythm of the heart, which can be used to try to prevent palpitations. If extra beats are enough of a problem to warrant treatment, then usually a beta-blocking drug will be used. These block the effect of adrenaline on the heart, and are also used for the treatment of angina and high blood pressure. However, they can cause increased tiredness, sleep disturbance, depression, impotence, and can aggravate asthma. Other anti-arrhythmic drugs can be used if beta-blockers are not appropriate, but they too have potential side effects.
If you have a sustained rhythm problem, it may be possible to convert the rhythm to normal by giving antiarrhythmic medication into a vein, but if this fails you may require cardioversion. Cardioversion is usually performed under a short general anaesthetic, and involves delivering an electric shock to the chest - this stops the abnormal rhythm and allows the normal rhythm to come through.
It is a good idea to go somewhere (GP's surgery or local hospital) if you have palpitations that have persisted for some time, even if you feel quite well with them. This is not because you will necessarily need to be admitted to hospital for treatment, but because an ECG performed during an attack will usually allow an accurate diagnosis to be made.
For some patients, usually those with a specific underlying problem shown on the ECG or one of the other investigations, an electrophysiological study may be advised. This involves inserting a series of wires into a vein in the groin (and/or the side of the neck) and positioning them inside the heart. Once in position, the wires can be used to record the ECG from different sites within the heart, and can also be used to start and stop abnormal rhythms so that a precise diagnosis can be made. If appropriate, i.e. if an electrical "short circuit" is shown to be responsible for the abnormal rhythm, then a special wire can be used to cut the "short circuit" by placing a small burn at the site. This is known as "radiofrequency ablation" and is curative in the majority of patients with this specific problem.
Atrial fibrillation has been dealt with in a separate article. Treatment may include medication to control the heart rate, or cardioversion to convert the rhythm to normal. You may require medication after a cardioversion to maintain a normal rhythm. In some patients, if attacks of atrial fibrillation are very common despite medication, ablation of the connection between the atria and the ventricles (with implantation of a pacemaker) may be recommended. A very important specific problem with atrial fibrillation is the increased risk of stroke, and management of atrial fibrillation will usually include some form of "blood thinning".
Very occasionally palpitations can be associated with an increased risk of complications such as blackouts, and even premature death. Generally speaking, serious arrhythmias occur in patients who are known to have heart disease (such as a previous heart attack, or significant valve abnormalities), or in whom there is a family history of serious arrhythmias, blackouts, or sudden premature death.
Palpitations in the setting of the above problems, or which cause blackouts or near blackouts, should be taken seriously. Even if ultimately nothing untoward is found you should contact your doctor as soon as possible to arrange the appropriate investigations if palpitations are associated with blackouts or if you have any of the features noted above.