The heart is a muscular organ which pumps blood to different parts of the heart and through the entire body. The contraction of the heart muscle is controlled by electrical signals. Normally, the heartbeat starts in the right atrium when a special group of cells sends an electrical signal. Anything that affects the muscle, blood vessels, valves or electrical signals in the heart can cause arrhythmia. There are many possible causes:

• dizziness
• lightheadedness
• fainting
• shortness of breath
• chest pain
• confusion

Some people have occasionally experienced a "skipped beat" – the heart seems to go faster or slower than normal, or starts to beat very hard. These are mild and very common types of arrhythmia. If you have noticed any of these symptoms, or if they make you feel uncomfortable, see your doctor.