Palpitation is the medical term for a forceful or rapid heartbeat. It is caused by a disturbance in the normal electrical pathways in the heart muscle. There are many different forms of palpitation. Although, feeling a forceful or rapid heartbeat can be unpleasant, the vast majority of conditions which result in palpitations are not dangerous.
Patients with palpitations experience a wide variety of symptoms including a pounding, fluttering, or irregular heartbeat, which may also be felt in the neck of throat. Other symptoms include breathlessness and a lack of energy. Most palpitations are sudden in onset and can last anything between a few seconds to many hours or days. In some patients a very fast heart beat can be associated with dizziness and in rare circumstances it can lead to loss of consciousness.
An ECG (heart trace) and 24-hour ECG monitoring (Holter monitor) are often adequate to reach a diagnosis. Patients should also routinely undergo an echocardiogram (ultrasound scan of the heart) or an MRI scan of the heart to ensure that there is no underlying abnormality in the heart muscle which may require specific treatment.
Common causes of palpitation are ectopic beats, atrial fibrillation (AF), and supraventricular tachycardia (SVT).
The heart normally beats at a regular pace. Extra heart beats that disrupt this regular rhythm are termed ectopic beats. Ectopic beats are very common and can arise in individuals with a normal heart or in the context certain cardiac conditions. In healthy individuals stimulants such as smoking and excess alcohol or caffeine (such as coffee and tea) are a common cause of ectopic beats. Other causes include unstable angina, myocardial infarction, or heart failure.
Patients complain of a pounding sensation in the chest which is often followed by a feeling that the heart has stopped momentarily.
Life style changes and a short course beta-blocker tablets (which dampen down the extra heart beats) are often adequate to treat most patients with ectopic beats. Ectopic beats are almost always treated on an outpatient basis.
Atrial fibrillation (AF)
Atrial fibrillation, which is usually referred to as AF, is a very common condition and results in a fast and irregular heart beat. It can affect all age groups. In addition, to palpitations patients often experience breathlessness and lack of energy. AF is not dangerous but the fast and irregular heart rate is often poorly tolerated.
As for ectopic beats, the causes of AF are very varied and it can occur in healthy individuals (in response to stimulants or infection) as well as in patients with heart problems (such as a heart attack or heart failure). In a proportion of people no cause for AF is identified. This condition is referred to as “lone AF”.
There are two approaches to treating AF – namely restoring a normal regular rhythm (a process called cardiovesrion) or controlling the fast heart rate. Both are equally safe and the choice of treatment depends on the condition of the heart. Cardiovesrion is preferred in people with a structurally normal heart. This is achieved through a small electric shock delivered under sedation to resynchronise the heart rhythm. In patients with an enlarged heart, cardiovesrion is unlikely to be successful, and it is preferred to control the heart rate. This is achieved with medication such as beta-blockers or digoxin.
In some patients where AF is recurrent or causes intractable symptoms sound waves can be used to inactivate the foci from which the irregular heart impulses originate (a process called radiofrequency ablation).
Under certain conditions AF can predispose to formation of blood clots in the circulation. If these blood clots travel to the brain they can cause a stroke. Therefore, it is imperative that patients with AF are treated with blood thinning medication (such as warfarin).
Most patients with AF are treated on an outpatient basis and only require admission to hospital to undergo cardiovesrion of radiofrequency ablation.
Supraventricular tachycardia (SVT)
SVT is a condition that effects otherwise healthy individuals and leads to a very fast regular heart beat. It arises as a result of abnormal electrical connections in the heart muscle. These abnormal pathways are often present from birth but may only result in symptoms as an adult.
Symptoms start abruptly without any warning and palpitations are almost always accompanied by breathlessness, dizziness and chest discomfort.
In the acute setting an SVT can be terminated using intra-venous medication such as adenosine. However, if this fails, patients will need to be cardioverted as for AF. SVT does not predispose to formation of blood clots and therefore there is no need to use blood thinning medication.
If SVT is recurrent radiofrequency ablation (see section on AF) can be used to permanently eliminate the abnormal electrical pathways. Radiofrequency ablation for SVT is highly effective and is a curative treatment in most patients.
Patients with acute SVT almost always require a short admission to hospital.
Other less common causes of palpitation
There are many other forms less common causes for palpitation. Some such as ventricular tachycardia (VT) can be dangerous and arise in patients after a heart attack on in the context of heart failure. Treatment of VT can be challenging and may involve medication, radiofrequency ablation, as well as special pacemakers (known as ICDs) which detect abnormal heart rhythms and immediately cardiovert the patient.