Heart palpitations are an awareness of your heart beat. They might feel as though your heart is 'racing', thumping or skipping beats. You might notice heart palpitations:

• during exercise
• at times of stress
• after consuming caffeine or nicotine.

Heart palpitations may or may not be associated with an abnormal heart rhythm.

Arrhythmias
Arrhythmias are disturbed rhythms of your heart beat. There are many different types of arrhythmias.

Some arrhythmias may make your heart skip or add a beat now and again, but do not affect your general health or ability to lead a normal life. Other arrhythmias are more serious. Without treatment, they can affect your heart's pumping action, which can lead to dizzy spells, shortness of breath, faintness or serious complications.

Many arrhythmia can be treated with medicines, surgery or other medical procedures. 

Different abnormalities of your heart's electrical system can cause different kinds of arrhythmias, including bradycardia and tachycardia.

Bradycardia (a slow heart beat) 
While bradycardia may be normal (for example, associated with improved physical fitness), it can also happen as a result of many physical disorders.

It is serious when your heart beats so slowly that it cannot pump enough blood to meet your body's needs. Untreated, bradycardia can cause excessive tiredness, dizziness, light-headedness or fainting, because not enough blood is reaching your brain.  

Tachycardia (a fast heart beat)
Tachycardia can be a normal response to physical activity. However, certain kinds of tachycardia are cause for concern.

Ventricular tachycardia is a potentially life-threatening condition that needs to be treated as a medical emergency. Treatment for this arrhythmia involves administering an electric shock to your heart using a special piece of equipment called a defibrillator. The electric shock 'resets' your heart so it can return to its normal rhythm.

Common types of tachycardia include atrial flutter and atrial fibrillation.

To find out about the causes, diagnosis, treatment and management of palpitations, use the navigation bar at the right of this page.

Resources
Long QT syndrome - information sheet (2004)  Download