Show AllThe heart has its own electrical system that organizes the activity of the four pumping chambers. The sinus node is the natural pacemaker of the heart and usually sends signals at regular intervals to the rest of the conduction system.
Occasionally, other areas of the heart can send signals that can activate the electrical system earlier than the sinus node. These are referred to as premature or early beats.
Early beats that originate in the atrium or upper chambers of the heart are usually referred to as premature atrial contractions or atrial premature beats.
Sometimes these early beats can arise from the ventricles or lower chambers of the heart and are then referred to as premature ventricular contractions or ventricular premature beats.
People with normal hearts can have these early beats quite frequently and not realize they are having them, while others are acutely aware of every extra beat of their heart.
Sometimes things that speed up your heart rate such as caffeine or stress can make these premature beats occur more frequently. Some people will have PACs in association with mitral valve prolapse.
In addition to single extra beats, runs of fast rhythms, or tachycardias, can be sensed as palpitations.
Some children, particularly young adults, are aware of rapid heartbeats that are due to the speeding up of the heart that naturally occurs in response to exercise or stress. This is called sinus tachycardia and is normal.
Some children have extra connections of the heart's electrical system that can speed up the heart rate in an abnormal fashion. These usually arise from the upper chambers of the heart and are referred as supraventricular tachycardias.
These types of fast heartbeats are usually more of a nuisance than dangerous unless they go on for hours at a time. There are also some fast heart rhythms that originate from the ventricles and are referred to as ventricular tachycardias.
These are dangerous rhythms and are usually associated with some other symptom such as dizziness or fainting.
What happens if my child has palpitations?
Premature beats are not dangerous and are very common. There are some situations however when these extra beats require further investigation.
If these beats are associated with other symptoms, particularly fainting, then they may actually represent a run of early beats. These early beats can interfere with the pumping of blood to the rest of the body, particularly the brain, and hence cause fainting. This can be life-threatening.
Children with certain types of congenital heart disease, for instance children with a Fontan connection, are at higher risk for having fast heart rhythms that can be dangerous.
A good history and physical examination will be helpful in determining the cause of the palpitations. Some children on further questioning will refer to palpitations as "skipping of their heart." This usually indicates PACs or even PVCs.
If a child describes their heart "racing" with a sudden start and stop, or a pounding of the chest, this is most likely a supraventricular tachycardia. Some children will appear sweaty or pale in association with this cause of palpitations.
If the child experiences fainting in association with the racing of the heart, this may indicate a ventricular tachycardia and should be evaluated by a physician immediately.
Most children with palpitations will have a normal cardiac exam. People with mitral valve prolapse have a very characteristic cardiac exam.
If their exam is not normal, the patient may have a structural problem with their heart that may be causing the palpitations (i.e., hypertrophic cardiomyopathy).
The physical exam may also give clues as to the function of the heart, which may be strongly associated with the palpitations.
In order to diagnose the problem, an electrocardiogram while the patient is experiencing the palpitations will be required. An electrocardiogram performed during an office visit will usually not show the rhythm disturbance but will help to rule out any structural reason for the problem.
Portable monitors that record the heart rhythm continuously over 24 hours (Holter monitor) are usually the most helpful to diagnose the rhythm.
If there is a high suspicion of a ventricular tachycardia, sometimes a more invasive electrophysiology study needs to be done in the cardiac catheterization laboratory to induce the fast heart beat under controlled conditions.
If the symptoms occur during exercise, an exercise test may be helpful in making the diagnoses.
Premature atrial and ventricular contractions do not need any therapy except avoidance of things that exacerbate them such as caffeine. If they are so frequent that they are a hindrance to normal daily living, there are some medications that can be used to try to control them.
There are a variety of pharmacologic and non-pharmacologic treatments for the other causes of palpitations. The key is to make the diagnosis, or at least to rule out any life threatening rhythms.
If a child has palpitations in association with fainting, this should be evaluated promptly.
